Volume 3

WPI-ADVANCED INSTITUTE FOR MATERIALS RESEARCH NEWS
September 12, 2008

2-1-1 katahira, Aoba-ku, Sendai 980-8577
Japan
Phone: +81-22-217-5922
FAX: +81-22-217-5129

September 12, 2008

Volume 3

World Premier International Research Center
Advanced Institute for Materials Research
Tohoku University

WPI-AIMR NEWSWorld Premier International Research Center
Advanced Institute for Materials Research
Tohoku University

Volume 3

WPI-AIMR NEWSN

September 12, 2008

AOMORIMORIOKAAKITAWorld Premier International Research Center
Advanced Institute for Materials Research

SENDAIYAMAGATASENDAI AIRPORT

Tohoku University

FUKUSHIMA

MITO
OARAI

Cover: Nano Materials with Regulated Endohedral Spaces by K. Tanigaki, Professor of WPI-AIMR
Thanks to the development of micro/nano-fabrication technologies, it is now possible to form various structures inTOKYOthe microscopic area, and even, when using atom manipulation technologies such as STM or AFM, to form much

NARITAAIRPORTsmaller patterns by moving atoms one after another. However, in the physical microfabrication process, emerging
SHINKANSEN(JR)

defects may become a large obstruction upon observation of solid-state properties expected in the nano region.
Moving atoms one-by-one to form a structure large enough to observe its solid-state properties requires a long

OSAKA

period. Various nano space materials formed in the nanometer range through application of self-organization
phenomenon are expected to constitute a new paradigm of material science that can provide possibilities for new
solid-state researches as well as various applications.

表紙：種々のナノ空間を有する物質群 （WPI-AIMR

谷垣勝己教授提供）

微細加工技術の進展により、現在では多様な微細領域の構造体が構築できるようになっている。また、STM や AFMなどの原子操作技術を用いれば、原子を１個ずつ動かして微細なパターンを形成することも可能である。しかし、物理的な微細加工では発生する欠陥がナノ領域で発現する物性を観測する際に大きな障害となり生じる。また、原子を１つ１つ移動させて物性を観測するために十分な大きさを有する構造体を構築するためには、膨大な時間が必要となる。自己組織化現象を適用することにより、ナノメートル領域に形成される種々のナノ空間物質は、多様な構造とともに新しい物性研究の可能性を与える物質科学のニューパラダイムとなる事が期待される。

KANSAIAIRPORT

World Premier International Research Center
Advanced Institute for Materials Research

Tohoku University

2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Phone : +81-22-217-5922
FAX : +81-22-217-5129
E-mail : wpi-oﬃce@bureau.tohoku.ac.jp
URL : http : //www.wpi-aimr.tohoku.ac.jp

WPI-AIMR NEWS

Volume 3

September 12, 2008

World Premier International Research Center
Advanced Institute for Materials Research
Tohoku University

Produced by the WPI-AIMR Communication OfficeDirector: Yoshinori Yamamoto
Editor, writer: Toshio Sakurai
Associate Editor, writer: Hiroshi Komatsu
Production coordinator: Yasunori Fujikawa
We welcome your comments, questions and involvement.
e-mail to: wpi-office@bureau.tohoku.ac.jp,orsakurai@imr.tohoku.ac.jp

Contents
Interviews
Koji SUMINO(Professor Emeritus, Tohoku University) ..................................................
Katsumi TANIGAKI (WPI-AIMR) . ...................................................................................

5
15

News Update
WPI-AIMR Annual Workshop 2009 .................................................................................
Masashi KAWASAKI ........................................................................................................
Mingwei CHEN .................................................................................................................
Akihisa INOUE .................................................................................................................
Peter V. SUSHKO ..............................................................................................................
Results of International Physics Olympiad .......................................................................
Research Grant ..................................................................................................................
Inauguration of new journal “Nano Research” ..................................................................

31
33
34
35
37
38
39
40

Research Prospect
Qi-Kun XUE ......................................................................................................................
Masaru TSUKADA ...........................................................................................................
Li-Jun WAN .......................................................................................................................
Tadafumi ADSCHIRI ........................................................................................................

45
55
65
73

WPI-AIMR Newly Appointed Research Staff ........................................................................

89

Adjunct Professors / Associate Professors ...............................................................................

117

WPI-IFCAM
Visiting Professorship and Workshop Support ..................................................................
List of WPI-IFCAM Visiting Researchers 2008-2009 ......................................................
Activity Report ..................................................................................................................

131
132
133

Announcement
Staff/post-doctoral fellowship .............................................................................................
Ph. D. student scholarship ...................................................................................................
International workshop guidelines .......................................................................................

141
142
143

Appendix
WPI-AIMR Administrative Office ......................................................................................
Directory ..............................................................................................................................

1

X-1
X-2

Editor’s note
We are excited to publish and distribute WPI-AIMR
News Vol. 3 to our friends and colleagues on
September 12, 2008, the first anniversary of theofficial announcement (September 12, 2007) of thefive awardees of WPIRC (World PremierInternational Research Center).
It has almost been a year since WPI officially started
on October 1, 2007 and we are now shaping up into afull-fledge research center in organization, personnel,
and infrastructure with new advanced equipment andnew buildings to house laboratories, offices andadministration.
Although this program was initially set as a ten-year
project, the first five-year critical review will be
coming up soon, indeed in less than three years.
Many, familiar with our program, commend ourassembly of strong individual principal investigatorsand our flagship ideal of “fusion among various disciplines” is most welcome in the 21st
century interdisciplinary science/ technology world. “Fusion” is indeed our buzz-word andgoal. (My friend at Seoul National University wrote to me “the interdisciplinary graduate
nano-science program is going to change its name to “Graduate School of Fusion
Technology,” while SNU is participating in a newly publicized “World Class University”
Program in Korea.)
However, saying is one thing and doing is quite another, as everyone knows so well. Now
we must deliver what we promised in our proposal, quickly and effectively. As noted in his
interview by Professor Komatsu, in this volume, Professor Emeritus K. Sumino, a pioneerof semiconductor defect physics, pointed out that successful interdisciplinary work (fusion)requires an assembly of talented first-class researchers who greatly excel in their own
disciplines and have open minds to unlimited possibilities.
The WPI Administration together with President Inoue are more than happy to assist the
fellow researchers on their research endeavors in any way possible. After all that is the only
purpose of this organization.
The results of the 39th International Physics Olympiad held in Hanoi, Vietnam, in July arelisted in the News Update section. These showings will have a strong impact in futureworld-wide research, while the vast majority of people were preoccupied by the 2008
Beijing Olympics. I must confess that P. R. China did really well in both Olympics.
In this issue, we have listed our new WPI members, both research staff and supporting
office staff who have joined us since October 1, 2007. Please welcome them all with open
arms. – Toshio Sakurai

2

Interviews

Interview with Koji Sumino, Professor Emeritus of Tohoku University

Introduction:
Professor Koji SUMINO: Born in 1931. Started academic life in 1953 as a graduate student of the Physics
Department at Tohoku University. Served as a research associate from 1956 to 1964, associate professor from l965
to 1973, professor from 1974 to 1995 and has been professor emeritus since 1995 at Tohoku University. Served
also as an executive advisor to Nippon Steel Corporation from 1995 to 2000. His main research field has been
crystal lattice defects and crystal plasticity, although his early work was mostly concerned with metals and alloys.
He proposed a new type of interaction of dislocations with atomic ordering in alloys. He also put forward theconcept of “surface dislocations” to describe the kinetics of the diffusionless migration of interfaces and applied it
to twinning deformation and martensitic transformation. He received the Meritorious Prize from the Japan
Institute of Metals in 1973 for his research on dislocations in metals and alloys. Changing his focus to crystal
defects in semiconductors in around 1965, heinvestigatedthedynamic

properties

ofindividual dislocations and the mechanicalproperties and strength characteristics of silicon,
germanium

andvariouscompoundsemiconductors. He succeeded in describing
macroscopicallyobservablemechanicalcharacteristics of semiconductors in terms ofvarious collective behaviors of dislocations,taking account of the effect of impurities. He
also greatly contributed to the progress of
production technology for high quality siliconwafers used in large-scale integrated circuits
through his basic research on defects insemiconductors.

5Prof. Koji SUMINO
東北大学名誉教授

角野

浩二

Reflection on Lattice Defect Physics Research and Materials Technology— Relationship between Fundamentals and Applications —Komatsu: Professor Sumino, you are an authority in Japan on dislocation theory, and you have been involved in
the development of the theory from its very beginning to maturity. Research on lattice defects is essential inunderstanding the physical properties of materials. Particularly in nanotechnology, lattice defects are unavoidable
problems. Today, I would like to ask you about the relationship between fundamentals and applications from yourexperience, reflecting on how lattice defect physics has developed over time as an academic discipline.
Sumino: In the mid-1970s, the level of integration of silicon devices rapidly increased, and this resulted in
growing demand for improved quality of silicon wafers for substrates. Controlling various lattice defects incrystals attracted attention as a key issue. In this historical context, as a specialist in crystal lattice defect physics, I
became seriously involved in silicon material technology. I remember that there were active exchanges between
fundamentals and applications, thus stimulating each other, and substantial advances were made in each of the twoareas. I remember that we had vigorous discussions some 30 years ago. Now, I don’t feel the sense of vigor thatexisted in the exchanges between these areas anymore.
In this interview, I want to talk about what the exchange between basic research into lattice defects and siliconmaterials technology was like, which was active some 30 years ago, based on my experience.

I will be happy if I

can make some contribution to revitalizing disciplines in this field by recounting my experiences.
Komatsu: I hear that dislocation theory was born out of an understanding of the mechanical strength of metals.
Why did you choose semiconductors as the topic of your research at some point?
Sumino: Strength characteristics, or the response of crystals to external forces, are typical physical properties ofcrystalline solids governed by the dynamic properties and behavior of dislocations. I entered this field of study in1953 and changed my research field from metals and alloys to semiconductors around 1965.
Originally, I was not much interested in the strength characteristics of semiconductors, which are not industrial
structural materials. Semiconductors were the only materials in which the velocity of individual isolated
dislocations in crystals could be measured highly accurately as a function of temperature and stress. This is why I
chose semiconductors.
The plastic deformation of crystals develops as high-density dislocations move in the crystal. Therefore, thestrength characteristics of crystals are determined by how highly dense dislocations are introduced into the
crystals under stress and what collective behaviors they exhibit. First, the kinetic properties of isolated
dislocations in crystals of a material are measured. Then, the strength characteristics of the crystals, which are6measured on a macro scale, are accurately determined. My aim was to carry out a quantitative analysis of therelationship between them, and thereby to investigate the details of various collective behaviors exhibited bydislocations during the deformation of crystals, and identify factors common to all materials that govern themechanical strength of crystals. This study was not possible with materials other than semiconductors.
Our group started research with germanium, and expanded the scope of research to include silicon around 1970.
All of the crystals used as samples were grown by the floating-zone (FZ) method and had high purity. We
determined experimentally that the strength characteristics of semiconductor crystals are very strongly governedby three factors: 1. the deformation temperature; 2. the deformation rate; and 3. the density of dislocations (ordislocation sources) contained in the crystal before deformation. A phenomenon that was specific tosemiconductors and not found in other materials was the rapid decrease in the strength of semiconductors withincreasing density of the dislocations initially contained in the crystal. Once the above three factors were
determined, the strength characteristics of the semiconductor crystals could be measured with good
reproducibility.
We successfully demonstrated that all observation facts can be quantitatively described by correlating thetemperature and stress dependence of the velocity of individual dislocations in these crystals with the dislocation
multiplication mechanism. Consequently, the characteristics of the general collective behavior of dislocations
during the deformation of crystalline solids were identified, and at this point the original purpose of my research
was achieved.
Komatsu: So, instead of putting priority on the relationship of semiconductor crystals with production technology,
you developed a basis for quantitatively understanding their strength characteristics. This was a benefit for theuniversity, wasn’t it? Studies born out of this kind of intellectual curiosity are directly linked to production
technology on the production floor.
Sumino: That’s right.
In carrying out research, I paid no attention to relationships with device technology. My research had nothing
to do with that. But in the mid-1970s, unexpectedly I was often approached by the semiconductor industry.
At that time, one of the major issues in the device manufacturing technology community was controlling andpreventing the occurrence of lattice defects (process-induced defects) during the device manufacturing process.
The issues brought to me were related to the occurrence of dislocations during thermal cycling performed on
silicon wafers.
I received the following information from the manufacturers’ engineers:(1) When a wafer is subjected to thermal cycling, dislocations and warping occur. The extent of dislocations
and warping is not significant at low thermal cycles, but rapidly increases when the number of thermal
cycles exceeds a certain value.
(2) Dislocations and warping are much less likely to occur in silicon wafers grown by the Czochralski (CZ)
process than in those grown by the FZ process, making CZ-silicon wafers stable against thermal cycling.
(3) The advantage of CZ-silicon wafers over FZ-silicon wafers in mechanical strength is not that significant at
low thermal cycles, but becomes rapidly significant when the number of cycles exceeds a certain value.
The manufacturers wanted me to investigate the reasons for this and give them effective guidelines to preventthe occurrence of dislocations in wafers and wafer warping. If you assume that the state inside a wafer is not7

affected by the number of cycles, you cannot explain the fact that the frequency of occurrence of dislocations andthe extent of wafer warping rapidly increase when the number of thermal cycles exceeds a certain value. The
cause is that in addition to the aforementioned fact that the mechanical strength of silicon crystals depends on thedensity of the dislocations initially contained in the crystals, dislocations occur locally in a wafer, move andincrease to higher densities, and consequently the strength rapidly decreases with an increasing number of cycles.
This was our conclusion. Also, we found that when a small mechanical stimulus is applied to the surface of anon-dislocated silicon crystal at room temperature using a needle, or fine powder, of diamond or carborundum, afine non-crystalline region surrounded by dislocations is formed around the stimulus point.
We found that when subjected to a temperature over 500°C, such a fine non-crystalline region is transformed
into a dislocated region with the same crystal orientation as that of the parent phase crystal, and that the thus
introduced dislocations move under thermal stress, the number of dislocations increases, and the crystal issoftened.
In other words, it became clear that silicon crystals believed to be non-dislocated at the stage of wafer
fabrication and forming are transformed into dislocated crystals during thermal processing if surface treatment is
not appropriate. I heard that after the publication of this study, wafer manufacturers changed theirsurface-treatment processing of wafers.
On the other hand, when FZ- and CZ-silicon crystals were tested in the normal strength test, there was no
significant difference between them, as long as non-dislocated crystals were used as test samples. Therefore, we
concluded that the difference in strength between the two types of silicon wafers is peculiar to deformation fromthermal cycling.
The difference between FZ and CZ silicon is the difference in the concentration of oxygen impurities in it. So,
we studied in detail what effects the difference in the concentration of oxygen impurities might have on
dislocations. Our study found that oxygen impurities in solid solution has no effect on the motion of dislocations,and oversaturated oxygen concentrates in static dislocations at high temperatures and immobilizes them.
From this, we concluded that the strength stability of CZ-silicon wafers during thermal cycling is due to the factthat dislocations due to thermal stress are immobilized by oxygen impurities when the thermal stress is removed,
and are inactive during subsequent thermal cycling.
As mentioned above, it became clear that issues involved in the occurrence of dislocations and warping due tothermal cycling of silicon wafers can be adequately addressed by properly taking into account the kinetic
characteristics of the occurrence, motion and multiplication of dislocations in silicon and the effect of oxygen
impurities on these processes. I heard that based on this knowledge, device manufacturers searched for the optimal
conditions to control the occurrence of defects under the restrictions of the characteristics of the device
manufacturing equipment and cost performance.
Komatsu: Could you tell me your idea on the relationship between fundamentals and applications?
Sumino: Let me explain the characteristics of knowledge required to answer the issues brought to us by thetechnology community. What was most required was a comprehensive and quantitative understanding of the
microprocesses governing the deformation and mechanical strength of silicon crystals. It was not obtained fromstudies aimed at application to device technology.
In addition to a general understanding of the deformation of crystals, it was necessary to account for the effectof oxygen impurities on the activity of dislocations to understand the characteristics of wafer response to thermal
8cycling. Even if the phenomenon of the locking and inactivation of dislocations by oxygen impurities was foundas an isolated finding, it would be impossible to obtain an overall view of the effects of oxygen impurities onwafer deformation. The findings would not have been effectively applied to technology.
Many phenomena are involved in technology. I would say that it is a self-evident truth that in order to create
something new, a comprehensive and proper understanding of all phenomena involved in it is essential. I
remember that it was Voronkov (Russian) who first succeeded in establishing a unified picture of grow-in defects
in silicon crystals, which attracted significant attention in the 1990s. He had comprehensive knowledge of thecharacteristics and behavior of point defects. What is absolutely required of those involved in technologicalinnovation is familiarity with related fields.
Recently, attempts have been made to develop devices using strained silicon. I think that controlling misfit
dislocations is important. Basic knowledge of dislocations is essential here. If we can accurately understandtemperature and stress changes during epilayer growth, we can predict how dislocations behave in the epilayers. I
can imagine that by comparing such predictions with actual phenomena, we can understand the special
relationship between the boundary structure and the occurrence of dislocations, and obtain important information
for technological development. Probably, success in technological development depends on how we can establish
comprehensive and systematic knowledge of activities of misfit dislocations during epilayer growth. What weneed to this end is detailed knowledge of the various characteristics and behaviors of dislocations in silicon
crystals.
I want to look back on the approaches the technology community made to me in the 1970s to 1980s. At the time,
we contacted several engineering managers engaged in the development of silicon materials in corporations. They
were from private companies, but contacted me as if they represented the industry. All of them had maderemarkable achievements in technological development in their respective company, and looked absolutely
confident in developing silicon materials.
They were not necessarily familiar with the field of lattice defects. But they were familiar with various
technical issues and raised issues to me, as a lattice defect specialist, in a very appropriate manner. We received a
lot of support in carrying out our research, but we were never told what to publish or what not to publish for the
results of the study. We were never asked by particular companies to contribute to their technological development
in return, either.
I sensed that, separate from their positions as corporate engineers, they sincerely hoped for the advancement ofJapan’s silicon material technology. Thus, they were highly qualified engineers with deep insight.
In the mid-1980s, device manufacturers withdrew from research and development of silicon materials, andthere were no experts on silicon materials left at device manufacturers. Issues such as quality control of siliconmaterials used in devices were left entirely in the hands of wafer manufacturers.
The reason behind this was that a huge additional capital investment was required for each increase in the
integration level of devices, whereas the issue of increasing the crystal quality of silicon wafers was believed to beaddressed by progressive improvements through practical experience at work, unless essential changes occurred indevice structures.
As a result, it became the top priority for wafer manufacturers to produce wafers meeting specifications set bydevice manufacturers and expand sales, and the motivation to develop original technologies from a long-term
perspective and to hold discussions was lost. This is how I feel.
Researchers in the field of basic research moved away from extensive research to investigate specificphenomena, using various research approaches, to gain an understanding from a broader perspective. Instead, they9

focused more on producing as many research papers as possible using the limited research approaches available tothem. It was a natural consequence that basic research and applied technology stimulated each other lessfrequently and the exchanges between them decreased.
There is one thing I want to add. I hear that recently there is an increasing sense of deadlock in the siliconmaterial technology community and an increasing number of experienced engineers are deciding to exit this field
during organizational changes. I think that it is undesirable in terms of the psychological effect on young
engineers entering this world. I think that appropriate action should be taken to give them hope for the future.
When a new fact is discovered, new ideas are developed based on it and a technological revolution occurs. Thisis a common occurrence. Engineers should always refine their skills and increase their knowledge of the scienceto prepare for a technological revolution to occur anytime.
Komatsu: Thank you for taking the time to tell us about the relationship between fundamentals andapplications from your own research experience.
July 26, 2008 at Prof. Sumino’s private room,
Transcript by Hiroshi Komatsu

10東北大学名誉教授

角野浩二先生にきく(Interview with Professor Koji Sumino−Japanese version)

格子欠陥物性研究と材料技術を振り返って--------基礎と応用のかかわり-------

小松：角野先生は転位論の揺籃期から成熟期にわたって深く関わられた日本の第一人者です。材料物性の理解で｢格子欠陥｣の研究は欠くことができません。とくにナノテク技術は格子欠陥は避けて通れません。今日は一つの学問体系が出来上がる過程をたどりながら、基礎と応用のつながりをご体験からお話いただきたいとおもいます。
角野：1970 年代の半ば頃からシリコン・デバイスの集積度が急速に増大し、それとともに基板となる
シリコン・ウェハーの品質の向上が要求されるようになりました。結晶に含まれる各種の格子欠陥を制御することが重要な課題としてクローズアップされたのです。そんな時代背景で結晶格子欠陥物性を専門とする私がシリコン材料技術と深い関わりを持つことになりました。
基礎と応用の間で活発な交流が行われ、双方が刺激しあってそれぞれの分野で大きな発展があったよ
うに記憶しています、あのころの生き生きとした交流の様子を思い出すと、30 年余りが経過した現在、これらの分野での交流の実態にあの頃の活気を感じることは私にはできません。
このインタビューでは格子欠陥の基礎研究と材料技術との間の交流が活発だった頃の状況を私の経
験をもとに振り返ってみます。これがこの方面の学問や技術を活性化する上で何らかの参考になれば幸いです。
小松：金属材料の強度を理解することから転位論が生まれたと聞いていますが、ある時点から半導体を対象に選ばれたのはどのような理由からですか。
角野：転位のダイナミックな性質や挙動によって支配される結晶固体の典型的な物性はその強度特性、
すなわち外部応力に対する結晶の応答です。私がこの分野に入ったのは 1953 年でしたが、1965 年頃研究対象をそれまでの金属や合金から半導体に移しました。
もともと、工業的な構造材料でもない半導体自体の強度特性にそれほど関心があったわけではありません。研究対象を半導体に移した理由は、それが結晶中の孤立した個々の転位の運動速度を温度や応力の関数として信頼度高く測定することが出来る唯一の物質だったからです。
結晶の塑性変形はその中で高密度の転位が運動することによって進行するので、その強度特性は、応力の作用の下で転位が結晶中にどのようにして高密度に導入され、さらに、それらがどのような集団的な運動挙動を示すかによって決定されます。同じ物質の結晶について、まず、その中の孤立した転位の運動特性を測定し、次いで、マクロな尺度で測定される結晶の強度特性を正確に調べる。そして、それらの間の関係を定量的に解析することにより、結晶が変形する際に転位が集団として示すさまざまな挙動の詳細を抽出し、それからすべての物質に共通な、結晶の強度を支配する因子を明らかにすることが私の狙いでした。これは半導体以外の物質では実行することが不可能な研究でした。
ゲルマニウムからスタートした私のグループの研究は 1970 年頃研究対象をシリコンに拡張しました。
試料として用いた結晶はいずれも帯溶融（FZ）法で育成した純度の高いものでした。
11これら半導体結晶の強度特性が次の３つの因子--- ①変形温度、②変形速度、それに③変形前の結晶に含まれている転位（あるいは転位発生源）密度----に非常に敏感に支配されることを実験的に確立しました。半導体に特有で他の物質に見られない現象は、その強度が最初結晶に含まれている転位の密度の増加と共に急激に減少することでした。以上 3 つの因子さえ決めればそれら結晶の強度特性は非常に再現性よく測定されました。
全ての観察事実が、これら結晶の中の個々の転位の運動速度の温度や応力に対する依存性、それに転位の増殖機構と結びつけて、定量的に記述できることを示すのにも成功しました。その結果、結晶固体が変形する際の転位の一般的な集団的運動挙動の特徴が明らかになり、この時点で私の当初の研究目的は達成されました。
小松：生産技術とのかかわりは二の次にして、学問的に半導体結晶の強度特性を定量的に理解する基礎を築けたのは大学のメリットですね。この知的好奇心から生まれた研究が現場の生産技術に直結する。
角野：そうです。それまでデバイス技術との関係など全く意識せず、それとは無縁な形で研究を進めてきた私でしたが、1970 年代の半ば頃、半導体産業界から急に積極的な働きかけを受けることになりました。
当時、デバイス製造技術界で大きな問題になっていたことの一つは、デバイス製造プロセス中に発生する格子欠陥（プロセス誘起欠陥）を制御・抑制することでした。私に持ち込まれた問題は、シリコン・ウェハーに繰り返し熱サイクルを施した際に起きる転位の発生と関係したものでした。
メーカー側の技術者から提供された情報は整理すると次のとおりです。
①ウェハーに熱サイクルを与えると転位の発生やそりが起きるが、それは熱サイクル数が少ない間は
顕著ではないが、サイクル数がある値を越すと急に増大する。
②チョクラルスキー（CZ）法で育成したシリコンのウェハーでは FZ 法で育成したシリコンのそれよ
りもはるかに転位発生やそりが起きにくく、熱サイクルに対して安定である。
③そのような CZ シリコン・ウェハーの FZ シリコン・ウェハーに対する強度的な優位も、熱サイクルが少ない間はそれほど著しくはないが、サイクル数がある値を超えると急激に顕著になる、などです。
これらの理由を解明して、ウェハー中の転位やそりの発生を抑えるのに有効な指針を示してほしいとのことでした。
熱サイクル数がある値を超えると急に転位の発生やウェハーのそりが大きくなるという事実は、ウェハーの内部状態がサイクル数に対して不変であると考えたのでは説明することは出来ません。シリコン
結晶の強度が最初結晶に含まれている転位の密度に敏感に依存するという、前に述べた事実と合わせて考えて、熱サイクル中に熱応力の作用によってウェハーの中で転位が局所的に発生し、運動し、増殖して、密度を増すために、強度がサイクル数の増加とともに急激に減少するのがその原因であると結論しました。
さらに、室温で無転位のシリコン結晶の表面にダイヤモンドやカーボランダムの微粉末や針によって軽い機械的刺激を与えると、その周りに転位を伴う微細な非晶質の領域が形成されることを見出しました。
このような微細な非晶質領域を 500℃以上の温度にもたらすと、母相結晶と同一の結晶方位をもつ有転位領域に変換されること、そして、そのようにして導入された転位は熱応力の下で運動し、増殖して結晶を軟化させることを突き止めました。
すなわち、ウェハーを加工・成型した段階で無転位であると信じられていたシリコン結晶は、表面処12理が適当でないと熱処理中に有転位結晶になってしまうことが明らかになったのです。この研究の発表
後、ウェハー・メーカーでは、ウェハーの表面処理の工程を変えたと聞き及んでいます。
一方、FZ シリコン結晶と CZ シリコン結晶を通常の強度試験でテストすると、無転位結晶を試料とす
る限り、両者の間には有意の違いは認められません。従って、これら 2 種類のシリコンのウェハー強度の違いは熱サイクルによる変形に特有のものであることを結論しました。
FZ シリコンと CZ シリコンの違いはその中に含まれる不純物酸素の濃度の違いですから、それが転位に対してどのような効果を与えるかを私のグループでは詳細に研究しました。その結果、固溶状態にある不純物酸素は転位の運動に何の影響も与えないのに対して、過飽和状態にある酸素は高温で静止した状態にある転位に集積し、それを不動化してしまうことを見出しました。
このことから、熱サイクルの際の CZ シリコン・ウェハーの強度安定性は、熱応力化で発生してくる
転位が、熱応力が働かなくなったときに不純物酸素によって不動化されてしまい、その後の熱サイクル
では活動できなくなることによるものであることを結論しました。
以上のようにして、シリコン・ウェハーの熱サイクルによる転位とそりの発生に絡む問題は、シリコン中の転位の発生、運動、増殖などの動力学的性質の特徴と、それらの過程に対する不純物酸素の効果を適切に考慮すれば、十分に対処できることが明らかになったのです。
こうした知識の上に、各デバイス・メーカーでは、デバイス製造設備の特性、コストパフォーマンス
などの制約の下で、欠陥発生を押さえるための最適条件の探索が行われたと聞いています。
小松：基礎的と応用についてのお考えをどうぞ。
角野：技術界から持ち込まれた問題に答えるために必要だった知識の特徴について考えてみましょう。
何よりも必要だったのは、シリコン結晶の変形や強度を支配する微視的な過程の総合的、かつ、定量的な理解でした。それはデバイス技術への応用を目的とした研究によって得られたものではありませんでした。
結晶の変形現象の一般的な理解の上に、転位の活動性に対する不純物酸素の影響を考慮して、はじめて熱サイクルに対するウェハーの応答の特徴を理解することができたのです。仮に、不純物酸素による転位の固着・不活性化という現象が単発的に見出されたとしても、それだけではウェハーの変形に対する不純物酸素の効果に関する全般的描像を得ることは不可能で、それを技術に有効に応用することは出来なかったでしょう。
技術には多くの現象が関わっているので、何か新しいものを生み出すためには、それに関与するすべての現象を総合的に正しく理解することが不可欠であるという自明の理がこの場合に実証されたということでしょう。
思い返せば、1990 年代に大きくクローズアップされたシリコン結晶の成長欠陥に対して、最初に統一的な描像を確立することに成功したのも、点欠陥の性質や挙動に関する総合的な知識に明るかったロ
シヤ人の Voronkov でした。技術革新に取り組む者にとって絶対必要なことは、関係する分野の学問に精通していることです。
最近、歪シリコンを使ったデバイスを作ろうとする試みが行われていますが、ミスフィット転位の制御が重要となると思われます。ここでも転位に関する基本的知識が不可欠です。
エピ層の成長中の温度や応力の変化を正確に知ることができれば、その中で転位がどのような挙動をするかは予測することができます。そのような予測と実際に起きることを比較すれば、界面構造と転位発生との間の特殊な関係などが明らかになり、技術開発にとって重要な情報が得られると想像されます。
技術開発の成否は如何にエピ成長の際のミスフィット転位の活動に対する総合的かつ系統的な知識を13確立できるかにかかっていると思われます。その際に必要なのは、シリコン結晶中の転位のさまざまな性質や動的挙動に関する詳細な知識です。
次に、1970 年代から 1980 年代にかけての私に対する技術界からの働きかけについて回想してみます。
その頃、私は企業でシリコン材料の開発に携わっている技術責任者の何人かと接触を持ちました。それらの人たちはそれぞれ特定の企業に所属しているにも関わらず、あたかも業界を代表しているかのような感じで私に接してきました。いずれも各企業で技術開発に目覚しい成果を挙げた実績を持っており、
シリコン材料の技術開発には絶対の自信を持っている様子が窺い知れるような人たちでした。
決して格子欠陥の学問に詳しくはありませんでしたが、技術的諸問題には精通しており、格子欠陥の専門家である私に対する問題提起の仕方が実に的を射ていました。私のグループの研究遂行上、ずいぶん便宜を図っていただいたこともありましたが、研究成果の発表に制約を求められるようなことは皆無
で、特定の企業の技術開発への見返りを求められることもありませんでした。
彼らは企業人としての立場を離れて、真摯に我が国のシリコン材料技術の発展を思っていることが伝わってくる、高い見識と資質を持った技術者でした。
1980 年代の半ばになると、デバイス・メーカーはシリコン材料の開発研究から撤退し、シリコン材
料に関するエキスパートはデバイス・メーカーからいなくなってしまいました。そして、デバイスに使うシリコン材料の品質のコントロールなどに関する問題は、専ら、ウェハー・メーカーの手に委ねられるようになりました。
その背景には、デバイスの集積度を上げるには、その度、新規に巨額の設備投資が必要になったことと、それに対して、シリコン・ウェハーの結晶品質の向上に関しては、デバイスの構造が本質的に変わらない限り、現場経験の積み重ねによる漸進的な進歩で十分対応できるとの判断があったのだろうと思われます。
結果的に、ウェハー・メーカーにとってはデバイス・メーカーが指定するスペックを満たすウェハーを製造し、販売を拡大することが至上命題となり、長期的視点から独創的な技術を開発したり、議論したりする機運が無くなってしまったように私には感じられます。
一方、基礎関係の研究者の間では、特定の現象をさまざまな研究手法を駆使して調べて、広範的な視点からの理解を得ようとする広がりをもった研究は少なくなり、手持ちの限られた研究手段を使って、出来るだけ数多くの論文を生産しようとする傾向が強まったようです。基礎研究を応用技術が互いに刺激しあうことは少なくなり、両者の間が疎遠になったのは、自然の流れでした。
最後に一言付け加えます。最近、シリコンの材料技術の世界では閉塞感が強まり、企業の組織変更などの機会に、自らの意思でこの世界を去っていく中堅の技術者が増えているのを耳にします。技術の伝承の上からも、新しくこの世界に入ってくる若い技術者への心理的影響の上からも、好ましいことではないと思われます。技術者に将来の希望を持たせるような何か適当な方策が考えられて然るべきではな
いでしょうか。
新しい事実の発見があれば、その上に新しい発想が生まれ、技術上の革命が起きることはよくあることです。何時そうなっても対処できるように、常に技術を磨き、科学に対する知識を高めて置くことが技術者の在り方だと私は思います。
小松：今日は基礎と応用の関連についてご自身の研究体験から貴重なお話をいただきありがとうございました。
(２００８年７月２６日、角野邸にて
14

小松

啓

記)

Prof. Katsumi TANIGAKI
主任研究者

谷垣

勝己

Interview with Professor Katsumi Tanigaki
A New World of Clustering Structures
Think Hard and Act Decisively; Failure is the Mother of Success

When I was small, there was no Internet and no computers games like today. Most of the time, children playedoutdoors. I was born in 1954 and during my childhood days, the possibilities of science sounded like a dream.
People talked about space travel by rockets. But what interested me most were robots. Robots at that time seemed
to be an unachievable dream, a fantasy. I imagined putting all kinds of artificial intelligence into a robot.
Imagination has no limit or boundaries, especially when you know nothing about it. Today, with too muchinformation and knowledge, it seems like everything is revealed and it is only a matter of whether you know it ornot.
Playing outdoors often consisted of making simple toys out of wood or bamboo. Despite their simple structures,it was quite difficult to make them. Making one that was satisfactory enough required much trial and error and I
spent hours elaborating them. This always came with many failures. I think this childhood experience formed thebasis of my current experiments. On the other hand, I feel that students nowadays know a lot, but are very
vulnerable to failure. They lack the strong will to keep on challenging to attain their goal, despite many failures.
And they give up too easily. They tend to favor goals that are easily achieved and they are not very resilient in
failure.
Looking back, I think I was always attracted to the electronics industry. At university, I majored in chemistry
and after graduating, I started working in a company. It was 1975, and at that time, the oil and medical fields were
the two most popular among university students looking for jobs because they offered good salaries, followed by
the electronics industry. My professor referred me to an NEC laboratory and I visited the lab. Fortunately, I wasoffered a job immediately. So, I had ample time to devote to my dissertation without being disturbed by job
hunting. However, NEC was not yet very well known then, and I remember my parents asking me, “What kind of
a company is NEC?”
Fundamental research laboratories at the companies of that time had much larger budgets than universities andalso owned a variety of equipment. It was the beginning of the fundamental research laboratory boom, the kickoffera, so to say, for fundamental research.
When I joined the NEC laboratory, other major Japanese company laboratories such as Hitachi, Mitsubishi and
Toshiba were actively engaged in magnetic bubble memory research. Through various events and social meetings,
I came to know many researchers working for different companies. I was engaged in magnetic bubble memory
research for a total of around six years. My research subject was “nanoprocessing” of bubble memory and the key
was how to miniaturize the memory. Cutting edge technology at that time could only miniaturize up to one micron.
To enhance its accuracy, we used the very first equipment developed by the Japan Electron Optics Laboratory,15

currently known as JEOL. As it was the very first of its kind, its materials were exposed. This study became thebreakthrough for me to enter the field of nanotechnology.
However, this research died out suddenly around the end of 1985 when IBM in the U.S. gave up bubble
memory research.
Surprisingly after that, we young researchers were allowed to plan and do research on whatever we wanted.
Thus, I switched from doing research into memory to looking for research themes, and I went out to look forresearch “seeds.”
At that time, the micro-fabrication accuracy of magnetic bubble memory was enhanced by one digit by using
electron beam lithography with inorganic memory materials. However, clouds seemed to loom over compound
semiconductors other than silicon, and I made a major decision to cut myself off from what I had been doing until
then.
I was also interested in the effects of radiation upon microfabrication. I came to hear about a study by the
Radiation Laboratory of Notre Dame University. So I applied for a sabbatical and with my own money, took off
for the U.S.
When I came back, I was surprised when the Personnel Department told me that I was going to be fired. I was
called in by the Fundamental Research Laboratory director Mr. Fujio Saito and went to see him, being anxiousthat I would be told the same thing. However, he only told me that he also experienced many challenges when he
was young and encouraged me to try whatever I wanted to do. He supported me in various ways afterwards. He
also advised me to study abroad for a few more years. But I declined his advice, because although research inEurope and America was far ahead of Japan in the 1950s, by the end of the 1980s, the gap had already narrowed
significantly. If I were to go to the U.S., I might be able to upgrade my English communication skills, but what I
really wanted to do was to make a molecular cluster thin film and for that purpose, I wanted an MBE. So I
declined his advice to study abroad and told him that I wanted 40 million yen instead. Surprisingly, the money
was granted, and to a youngster only in his mid-thirties! That was how I began my cluster research.
At that time, we young researchers at NEC shared a strong determination to be the ones to lead the fundamental
research field. Many of my former NEC research colleagues now are in the frontline of research. To name a few
off the top of my head, limited only to researchers working on crystals, I can think of Sumio Iijima (Meijo
University), Taketoshi Hibiya (Keio University), Junji Matsui (Himeji Institute of Technology), Koichi Kakimoto(Kyushu University) and Fumio Shimura (Shizuoka Institute of Science).
In the meantime, I taught Japanese to foreigners free of charge. In exchange, I was able to learn English
communication free of charge. At the NEC Tsukuba Laboratory, there were about 15 or 16 foreigners who camefrom the U.S., the U.K., France, India, Romania and other countries, which gave us an opportunity tocommunicate with people from different countries and to get to know different cultures. One of them is now auniversity professor in the U.S. Another was the daughter of Professor Hart of Oxford University. She came to
Japan as an exchange student. As I had to speak English to teach Japanese, it gave me good practice in speaking
English.
Looking back, there was a highly intellectual team with a good atmosphere at NEC Tsukuba at that time. We
inspired each other both in terms of our research and our cultures. Those were the good old days.
Now, companies have a different standpoint. The relationship between universities and companies has reversed.
I think that universities should, of course, engage in fundamental research, but also focus more on application
studies and broaden their research fields. WPI can be a part of that. I expect Japanese researchers to have stronger
aspirations and to take on more global challenges. The charisma that Japan used to have is now diminished. Japan16

now has less appeal to students from India and other Asian countries. Added to that, fewer Japanese students go
abroad. WPI can contribute to a breakthrough in changing this situation. However, the younger generation has lessintellectual hunger to begin with.
Students nowadays do not think within the framework of practical science and tend to stick to textbooks. They
seem to think that there is an answer to everything. When you think this way, you cannot generate innovative newideas. The answers that students present have very little sense of reality. When I say, “We don’t know, so let‘s tryit,” the words seem to sound like a threat to them. Perhaps they do not think hard as often as my generation used
to do. They are not resilient when being scolded and are extremely sensitive and vulnerable. There are fewer
students who can take part in heated debates.
One of the missions of WPI is to nurture young researchers. I hope that it will not just be a means to grant funds
for research, but that it will be an opportunity for young Japanese researchers to be inspired by foreign students
and to eagerly absorb their good points.
Going back to the story of my research, my first study was on the formulation of the phthalocyanine thin film
crystals using molecular beam epitaxy (MBE). This was the only molecule that could be regarded as a cluster backthen in 1986.
It took a long time to obtain an ultra-high vacuum of over 10-8 Pa. At that time, there were three groups engaged
in molecular semiconductor film formation research: the Hara group at RIKEN, the Maruyama group at theInstitute for Molecular Science, and our group at NEC.
In academic circles, the Japan Society of Applied Physics was the society that I was most involved in. Amongwhich, the most active society was the Organic Molecule/Bioelectronics Group established by the late Professor
Masakazu Okada of Hiroshima University. This group now has over 900 members. When it was established, I wasin my thirties. Professor Okada asked me to be its organizer. I declined immediately. “I want to devote myself toresearch, I do not want to waste my time on other things,” I told him. Even so, four years later, I was asked to be
an organizer again. This time I accepted, and was an organizer for six years.
Since around that time, there were many new developments in molecular semiconductor studies. C60 was
developed between 1989 and 1990, and became the theme of a study awarded the Nobel Prize. Inspired by that, I
became more focused on clustered molecular semiconductors. MBE was very useful for that purpose. We had avery good engineer, who was very helpful in improving the equipment. He had only graduated from high school,
but possessed an ability far exceeding that of the average college graduate. When he was faced with something he
did not understand, he studied on his own and searched for solutions. He still works at NEC and is contributing
greatly to their research. Engineers like him are crucial for research.
I repeatedly said that I did not need anyone working under me because I thought that teaching others would be awaste of time. However, two or three years after the Fundamental Research Laboratory was established, Mr.
Hisatsune Watanabe, the laboratory director, came to my office one evening and asked me if I would like to havesomeone working under me. In the end, I got a new researcher. She turned out to be a major contribution to myresearch. She is still engaged in research at NEC’s laboratory in Tsukuba. By the time I left NEC, I had eight
members of staff.
One special member of staff was Mr. Thomas Ebbesen. He is from Norway and is the son-in-law of the late Mr.
Iwao Hayashi. He is the same age as me and we got along very well. We are still in contact with each other. I thinkand behave in a Japanese way and tend to be quiet even when I have something I want to say, but Thomas always
stated his opinions straightforwardly. This was very helpful. We made a good team.
17

Around 1998, company research started to see a downturn. At that time, I was a research team leader. I was
given the same pay and treatment as a general manager, but I did not like the managerial job. Then, I received anoffer from a university and decided to leave NEC. My good research partner, Thomas, also left for France. He is
now Professor and Director of the Nanotechnology Center at the University of Strasbourg. He and his wife, who isthe daughter of the late Mr. Hayashi, have twin children.
Around 2001, fundamental research became not to be active like before. And this trend accelerated. Laboratory
directors with science and engineering backgrounds used to think first what is best the lab. But that has changed
and I had to spend more time on administrative procedures to raise research funds. To cope with the procedures
demanded, not by the researchers but from the administrative department, I have to handle more paperwork.
When I was leaving NEC to take up the position of professor at the Graduate School of Science at Osaka City
University, Mr. Rangu and Mr. Igarashi, who were NEC directors at that time, allowed me to take with me atruckload of the equipment I was using so that I could continue my research. Perhaps such generosity is
unthinkable today. Thanks to that, I was able to carry on my research without any break. Six years later, when I
received an offer from Tohoku University, I was allowed to take my equipment with me. I feel very grateful.
At that time, we were able to state our opinions openly and straightforwardly and often had heated debates.
Even when it led to a quarrel, it sometimes ended up in a better understanding of each other. Company researchers
are highly motivated. On the other hand, students have various demands and each one has to be treated in adifferent manner. They are extremely sensitive, and thus, I have to be very careful. What I regard as a mere
discussion may be mistaken for a scolding. Perhaps if there were members of staff of different generations like ina family, it might help. Universities are based on the American system, in which each professor or associate
professor forms an independent unit and has little contact with the others. This makes the accumulation andpassing on of research experience difficult, especially for experimental research. I hope that the Ministry of
Education and Science will reconsider and restructure this system. I think it is time to change the structure andallocate researchers according to their field of research. I think it would be better if a minimal unit consisted of
one professor, one associate professor and one assistant professor, though two associate professors would be better.
It is also important to nurture engineering administrators. The current system seems to be managed by people withliberal arts backgrounds who know little about actual research, thinking only with their heads. In the United States,
unlike Japan, a large amount of money is spent on utilizing human resources with doctoral degrees.

18Going back to research again, when the development of carbon clusters such as C60 brought attention to thisfield, I was able to keep up with the trend as I had established a basis from my previous research. Since around1990, researchers were able to make compounds from silicon or germanium crystals which were until thenunthinkable. Taking silicon as an example, it became possible to make clustered single crystals, not with theconventional diamond structure, but with different structures.
Figure 1 is an example of that model. It is a silicon polyhedron with a clusteredstructure and covalent bonds. And this is a perfect single crystal. Although it isformed 100% from silicon, it may also be possible to form it from carbon.
−

Symmetry of the crystal is Pm3m. The reason why it was not possible to form it
from phthalocyanine before was because the molecules are in the form of plates
and this tended to cause mismatches in the pile while blocking. But currently, it ispossible to form many perfect cluster-structured crystals.

Figure 1

Moreover, there is a whole variety including polymorphisms. It is definitely like a Columbus’ egg. Before,
nobody thought it was possible and did not even venture to try it. A variety of new materials were created between
1991 and 2000. And the method of creation is by no means limited to MBE, but various other methods are
currently being tried.
As you can also see from this crystal model, there is a hollow center in the unit cell. If you put an atom or amolecule in here, you can break its symmetry. When the symmetry is broken, a new property will emerge. For
example, it may be possible to change independently electrical conductivity and thermal conductivity, which arenormally correlated. This makes it possible to create a material with high electrical conductivity but extremely low
thermal conductivity. This kind of material is very useful when converting heat into electricity. Previously, it was
impossible to create this kind of material.
Unlike other inorganic semiconductors, in these clustered materials it may be possible to control holes andelectrons with high accuracy. Thus, various new developments are expected. Flexible clusters are formed fromlight elements listed up to the third row of the Periodic Table. Unlike heavy metals, they turn out to be materials
with lower environmental load.
I think my generation entered this field during the heyday of semiconductor research. We saw with our own
eyes semiconductor technology developed to its limits. Now, the tide is turning towards new materials.
Knowledge of chemistry will be very useful in the development of new materials.
I actually did organic composition for about three years during research into EL luminous molecular materials.
Once a student at the Tokyo Institute of Technology named Saotome who was majoring in organic compositioncame to our lab. We were forming organic molecules which we had designed ourselves. Surprisingly, he found theroutes one after the other very quickly. Inspired by him, I decided to study and train under his instructor, Professor
Endo of the Tokyo Institute of Technology (who later became President of the Society of Polymer Science) and
Mr. Takada (currently professor at the Tokyo Institute of Technology) for three years. Organic composition issimilar to cooking. It requires a certain sense. In the end, I realized that I lack this sense. When a person withcomposition sense sees a target, they can easily picture a route to that goal. It takes only two or three days for a
person with that kind of sense to form what would take me one year. It was very impressive. Mr. Saotome later
moved on to the field of biology and is now engaged in bioscience research in Boston.
I have lived through very good times, having had the chance to move through a series of experiences fromcrystal forming to its processing. And as people did not pick so much on failures, I was able to devote myself to19

my research without worrying about other things.
WPI offers good opportunities. I hope we make it into a program that attracts and appeals to students from
Europe and America.
I haven’t talked about the old days for quite a while. It brought back a lot of memories and I guess I have talked
a lot today. Nowadays, there is less dialogue between people. Before, on Saturdays, we used to study and work inthe mornings, and afternoons were off. That system was pretty good. When the seminar was over, we went out tohave a drink and had a good time. I feel that kind of atmosphere still remains in Sendai. And Sendai is not a largecity. You can walk from one end of the city to the other. This is also good.
Time seems to flow slowly in Sendai. In Tokyo and Osaka, you feel that you are always being driven bysomething. I hope we continue to take good care of the wonderful nature and environment that Sendai offers us.

June 16, 2008, at Tanigaki Laboratory,
Department of Physics, Faculty of Science at Aobayama Campus,
Transcript by Hiroshi Komatsu

20

Nano Materials with Regulated Endohedral Spaces
atom-scale Materials with Regulated NanospaceÅ

atomicmanipulation

micrometerμm

nm
pyrochlore

clathrate

skutterudite

AB2O7

A8B16C30

LnT4X12

Variety in geometry

micro-construction

Variety in host-guest interactions
Endohedral Nanospaces

Nanonetwork Polyhedral Solids
Intra-phonon

Lattice phonons

Aomic phonons (rattling)

carrier doping

carrier doping

New electronic statesdInter-space control
carrier doping
21

atomic motion

ph‐rattling‐ph interaction

e‐ph interaction

Intra-cage rearrangement
Low thermal conductivity
Jahn-Teller Distortion
Ge100
Superconductivity(III-IV)
46

Si100

22

WPI-AIMR

PI 谷垣勝己教授にきく（Interview with Professor Katsumi Tanigaki−Japanese version）------クラスター構造の新世界-----−熟慮断行、失敗は成功のもと−
子供の頃は今のようにコンピュータやゲームなどは無く、外で飛びまわって遊ぶことが主でした。私は１９５４年生れですが、当時は科学は憧れでした。宇宙ロケットの旅行などいろいろありましたが、中でもロボットにもっとも興味を惹かれました。ロボットは夢のユメでした。人工知能など自由に中に組み込むこともできるかもしれない。何もよく知らないから夢も大きくふくらませることができました。
ところが、情報量が多すぎる今は何もかもわかっていて、それを知らないだけといった感じです。
外で遊ぶことの中には木や竹を切って、自分で細工し、杉（玉）鉄砲や竹トンボを作ったりすることがありました。作るのは意外にむつかしい。満足のゆくまで仕上げるにはいろいろな工夫が必要で、夢中になりました。遊び道具つくりに失敗はつきものです。その原体験が私の実験を支えていると思います。ところが、今の学生は頭デッカチで失敗に弱いようです。多少失敗があっても、目的の達成のためにはぶつかってゆくといった気力が薄く、すぐ止めます。どうしても、楽して結果が得られやすいものに流れてゆくなど、失敗に対する抵抗力が落ちています。
ふりかえると、私は一貫して電子産業に憧れていたと思います。大学では化学を勉強した後企業にゆきました。１９７５年当時は石油産業と医療関連は給料がよくて人気があり、電子産業はその次でした。
先生の紹介で NEC の研究所を訪ねたところ、好運にも就職がすぐに内定し、落ち着いて研究論文をまとめることができました。もっとも、当時 NEC はよく知られていなかったので、親に『NEC ってどんな会社だ？』と聞かれたりしました。
当時の企業の基礎研究所は、大学よりも予算が１ケタから２ケタ多く、装置も色々ありました。基礎研究所ブームのはじまりで、まさに基礎研究のキックオフのときでした。
入所した時は磁気バブルメモリーの研究が日立、三菱、東芝など日本の大企業の研究所で盛んになされていました。懇親会などを通じていろんな企業の研究者と知り合うことができました。この研究をかれこれ６年ほどもやりました。私のテーマはバブルメモリーの「ナノ加工」で、メモリーをいかに微細化するかが研究の大きなカギでした。当時のトップ技術は１ミクロン止りでこの精度向上のため、部品がむき出しの日本電子製の１号機を使いました。このときの研究が「ナノテク」に参入するきっかけになりました。
しかし、米国の IBM が、バブルメモリーの研究に見切りをつけた１９８５年末頃から研究は急に立
ち消えになりました。
その後なんと、若い人は自由に夢を描いて好きなことをやってよいということになったのです。記憶研から探索研になり、研究のシーズ（seeds）探しに向ったのです。
磁気バブルは無機材料によるメモリーで、微細加工精度を電子ビームで１ケタ上げることが出来ていました。しかし、シリコン以外の化合物半導体には陰りも見えていたので思い切ってこれまでのものか
ら離れてみようと考えました。
さらにその頃は微細加工の時の放射線の影響も気になっていました。たまたま米国のノートルダム大学の Radiation Laboratory の研究を知り、休暇の手続きをして自分のお金で米国に出て行きました。
帰国して驚きました。人事係から「首だ」と言われたのです。基礎研究所長に会いに行けと言われて23

覚悟を決めて所長の斎藤富士朗さんに会いました。ところが所長は、自分も若い時はいろんなことをやった。いいから好きなことをやれと言われ、その後、随分と支援していただきました。さらに、２年くらい外国留学して勉強することを勧められたのです。しかし留学は断りました。なぜかというと欧米の研究は５０年代には日本よりはるかに進んでいたのですが、８０年代末頃は差が小さくなっていました。
米国留学で英会話は多少上手になるかもしれないが、それよりも分子のクラスター薄膜を作りたい。そのため、MBE の装置がほしかった。そこで留学は断り、その代り４０００万円ほしいといったら、なんとそのお金を出してくれました。まだ３０歳半ばの若者にです。それがクラスター研究のはじめです。
当時は自分たちで基礎研究をリードするぞという雰囲気が満ちていました。現在も第一線で活躍している NEC の出身者には、結晶関係に限ってもすぐ思いつくだけで、飯島澄男（名城大学）、日比谷孟俊（慶応義塾大学）、松井純爾（姫路工業大学）、柿本浩一（九州大学）、志村史夫（静岡理工科大学）の諸氏がいます。
英会話の方は、ボランティアで日本語を外国人に教えることで逆にタダで英会話を学習できました。
当時のつくばの NEC では、米、英、仏、インド、ルーマニアなど１５〜６人の外国人と国際的な交わりが普段に行われていて、互に異国のカルチャーを知る機会がありました。その中から今では米国で教授になった人もいます。オックスフォード大学のハート教授の娘さん（交換留学生）もいました。日本
語を教えるのに英語を使いますので実地の会話のトレーニングになりました。
あとから考えると、あのころのつくばの NEC は研究にもカルチャーにも、良い頭脳集団があったことになります。良い時代でした。
今は企業の立場は変わっています。大学と企業の関係が逆になりました。大学は基礎をやるのはもちろんですが、もっと応用に眼を向けて、研究に拡がりがある方がよいと思います。まさに WPI はその一環となり得ます。日本から世界に打って出ようという気概がもっと成長するとよいですね。以前は日本にもカリスマ性がありましたが、最近では消えてきて、アジア、インドの学生を引きつけるものが少なくなっている。日本の若手も出てゆかない。WPI でも口火は切れるが、若手に知的な渇きがなくなっています。
最近は実学でなく教科書の中で生きている。全てに解があると思っている。これでは一定以上に新し
いものは出て来ない。学生の答えに現実味が薄いです。わからないからやってみようというのは彼らには脅威に聞こえる。じっくり考えることが無くなっているのではないでしょうか。怒られることに対して抵抗力がなく、ものすごくナイーブです。白熱的な議論ができる学生が少なくなってきました。
WPI は若い人の育成も兼ねてはいるが、お金ではなく、外国の学生から刺激を得てよいところをどん慾に吸収することを望みます。
ところで研究に戻りますと、最初に手がけたのはフタロシアニンのクラスターの MBE による構築です。これが１９８６年当時知られていた唯一のクラスターと考えることのできる分子でした。
10-10Pa を越える超高真空を得るには時間がかかりました。当時、実際に分子半導体成膜をやっていたのは理研の原グループ、分子研の丸山グループ、それに NEC の私の３グループでした。
学会では応用物理学会が中心で、中でも広島大学の故岡田正和先生の提唱で生れた「有機分子・バイ
オエレクトロニクス分科会」が活発で、会員は今では９００名を超えるようになっています。創立当時、私は３０代だったが岡田先生に幹事をやれと言われてすぐ断りました。私は研究をやりたい、無駄な時間を使いたくないと返事しました。しかし、４年あとには再度の依頼で幹事を引受けることになり６年間務めました。
その頃から分子半導体が伸びてきました。８９〜９０年にかけて C60 が出てノーベル賞になった。それがヒントで、より力を集中してクラスター分子半導体をやるようになり、以前からの MBE の装置が大変役立ちました。その時、優秀な技術者がいて装置の改良などですごく助かりました。その人は高卒
24

ですが並の大卒が及ばない能力を持った人でした。わからないことは自分で勉強していました。今でもNEC にいて重宝されています。このような技術者がいることはすごく大切です。
しかし一貫して、私は部下は不要と言っていました。教えることに使う時間がムダになると言っていました。ところが基礎研究所が出来て２〜３年たった頃、渡辺久恒所長が夜中に研究室に入ってきて、部下を取らないかと言ってきました。結果的には女性の研究者をすすめられて、研究にプラスになりました。その方は今もつくばで研究しています。NEC を出る時には部下は８名になっていました。
その中で異色だったのは故林厳雄さんの娘さんのご主人のエブソンさんです。その人はノルウエー人でした。私と同年齢でウマがよく合いました。今でもお付き合いしています。私は日本的で、言いたいことも我慢する方ですが、彼は全く遠慮せず、バンバン意見を言ってくれて、助かりました。良いコンビでした。
１９９８年頃になると企業の研究にも陰りがみられるようになりました。部長待遇の研究チームリーダであった私は管理する仕事が肌に合わないでいるとき、大学から誘いがあって NEC を出ました。コ
ンビだったエブソン氏も私と同時期にフランスへ移りました。彼は今ストラスブルグ大学のナノテクノ
ロジーセンターの教授（センター長）をしています。林さんのお嬢さんとの間に双子に恵まれて。
２００１年頃には基礎研究が下火になり、NEC のみでなく日立なども企業の研究のトップには文系の人たちが増え、それを加速させました。かつて理系の代々の所長は研究所を守ってくれたのですが、しだいに研究費を得るための事務手続きに時間を取られることが多くなりました。研究者でなく事務方の要求で、作文書きが必要以上に増加しています。
大阪市立大学理学研究科へ教授として移る時、当時の上層部である覧具さん・五十嵐さんは、研究を続けられるように私が使っていた装置をトラック１台分も持たせてくれました。今では考えられないこ
とかもしませんね。お陰で研究を中断することなく続けられました。数年後、東北大から声がかかった時、使っていた装置は移管することができました。私は大変感謝しています。
当時は言いたいことを本気で出せて、熱い議論ができた。ケンカもしたが、それで分かり合えたこともある。企業の研究者は強いモチベーションを持っている。しかし、学生は要求がいろいろで同じには扱えない。すごく傷つきやすいので気をつかいます。こちらは普通の議論をしているつもりでも、怒られていると勘違いされる。その時、家族のような世代構成のスタッフがいればよいのですが….。アメリカ式で教授、准教授がそれぞれ小さく独立していて、特に実験系では、研究の積み重ねや継承がむつかしい。このようなシステムは文科省も一度見直してほしいです。分野によって研究者の構成配置を考える時だと思います。教授、准教授、助教の１、１、１が最小の構成単位、できれば１、１、２がよいと思います。あとは、技官を育てることが大切です。現在は研究の実態を知らない文系の人が頭の中だけで考えているようです。米国は日本と違って膨大なお金を手配してポスドクを活用しています。
ふたたび研究の話に戻りますが、C60 などの炭素系のクラスターが出て、この方面に注目が集まった
時、私はそれまでの研究を土台にすぐ対応できました。１９９０年頃からシリコンやゲルマニウムの結晶では思いもよらない化合物ができるようになった。例えばシリコンですが、これまでのようなダイヤモンド構造でなく、別の構造をもったクラスター状の単結晶ができるのです。
図 1 の模型がその例ですが、共有結合でシリコン多面体のクラスター構
造を作っています。しかもこれは完全な単結晶です。１００％シリコンでできていますが、炭素などでも出来る可能性を持っています。結晶の対称−性は Pm3m です。昔フタロシアニンでは出来なかったのは、分子が板状
図 1で、ブロック化するときに積み重なりの不整合が出来易かったからです。今ではこのようなきちんとしたクラスター構造の結晶が多数できるようになっています。しかも多型もあって多種多様です。まさに、25

コロンブスの卵で、昔は初めから出来ないだろうとあきらめて、誰も試みなかったものです。C60 のフラーレンがヒントです。包接化合物の三次元版ともいえます。
１９９１年〜２０００年の間にいろんな新物質が生み出されました。作り方も MBE のみでなく、加圧・減圧さまざまな試みがなされています。
この結晶モデルでもわかりますが、ユニットセルの中に中空があります。ここに原子や分子を入れることで対称性を破ることもできます。対称性が破れることで新しい物性が出現します。たとえば相関する電気伝導度と熱伝導度をそれぞれ独立に変えることもできます。電気伝導度が高くて熱伝導度が低い物質も可能です。これは熱を電気に変換するとき大変役立ちます。今までこのような材料は作れませんでした。温度差を大きくとることで熱の変換効率を向上させることもできます。
これらの、クラスター物質では、通常の無機半導体と異なり、ホールとエレクトロンの高精度の制御が可能となる可能性があり、今後多様な展開が期待されています。また、柔軟性のあるクラスターは周期律表の第３周期までの軽元素でつくられます。これは重金属と違って環境に負荷を与えることが少な
いものになります。
考えてみると私たちの世代は半導体の隆盛期に研究に入り、その極限まで技術が展開するのを見たことになります。ここにきて新しい材料に向う気運が高まってきたのです。このような物質を開拓する上で化学の知識が大変有用になります。
実は私は EL の発光分子材料の研究をする目的で、有機合成を３年ほどやった経験があります。ある時、有機合成専門の早乙女君という学生が東工大から来ました。有機分子を自分で設計して作るのですが、短時間にその道筋を次々と見つけてしまうのです。これに刺激されて東工大のその学生の遠藤先生（のち高分子学会会長）と高田先生（現東工大教授）に弟子入りして、３年トレーニングを受けました。
しかし、有機合成には料理と同じでセンスがいります。結局、自分にはこのセンスが欠けていると思いました。合成のセンスのある人はターゲットを見たら、そこに至る経路を次々と描けるのです。よくできる人は、私が１年かけて作るものを２、３日で作ってしまう。すごいです！早乙女君はその後生物学に移って、今では米国のボストンでバイオサイエンスをやっています。
結晶作りから加工までを一貫して体験できる、大変よい時代を過しました。失敗を大目に見てくれたので、のびのび研究できました。
WPI は良い機会ですが、欧米の学生が自発的に来たくなるようなものにしたいですね。
今日は久々に昔話をしましたが、つい若い時を想い出し長話をしてしまいました。今は対話が欠けることが多いです。昔の土曜日は今ありませんね。けっこう良かったです。ゼミのあと、皆で飲み会をしながらパーとやりました。仙台はまだそんなことができる雰囲気が残っていますね。街を端から端まで歩けるのもいいです。
仙台は時間がゆっくり流れています。東京や大阪は何かに追われている感があります。この良い自然環境を大事にしたいですね。
（２００８年６月１６日、青葉山理学部物理学科

26

谷垣研究室にて小松啓記）

ナノ固体物性とデバイス基礎理学
原子領域

Å

nm領域

ナノ領域の閉じ込め空間

マクロ領域

μm

微細加工技術

原子操作

FET

シリコン結晶グラファイト結晶

薄膜成膜
sp3-ネットワーク
sp２-ネットワーク
微細加工

集積回路

27

News Update

WPI-AIMR Annual Workshop 2009
We cordially invite all WPI-AIMR members and our friends to the WPI-AIMR Annual Workshop 2009
to be held at Miyagi Zao Royal Hotel(http://www.daiwaresort.co.jp/zaou/) from March 1 to March 6,
2009.
The format of the technical sessions is similar to many of summer Gordon Conferences: relaxedatmosphere in the morning and evening sessions and a plenty of free discussion time in midday. Only
the exception is that we plan to publish proceedings in Springer “Advances in Materials Research”
series.
Since this will be the first one for our WPI, we are quite open to constructive suggestions and input
before we finalize the format in detail (by the end of January 2009). Please feel free to give us yourcomments.
Followings are tentative list of invited speakers at this time:
Toyonobu Yoshida, Department of Materials Engineering, University of Tokyo
Subra Suresh, MIT, USA (pending)
Kunio Takayanagi, Tokyo Institute of Technology (pending)
Manfred Ruhle, Max Planck Institute for Metals Research, Germany
Steve Pennycook, Oak Ridge National Lab. USA
Ke Lu, Institute for Metal Research, China Academy of Sciences, P.R. China
Akihisa Inoue, Tohoku University
William L. Johnson, California Institute of Technology, USA (pending)
Lindsay Greer, University of Cambridge, UK
C. T. Liu, Oak Ridge National Lab. USA (upending)Juergen Eckert, IFW Dresden, Germany (pending)Hans-Joachim Freund, Department of Chemical Physics, Fritz-Haber-Institut, Germany
Hong Guo, Department of Physics, McGill University, Canada
H. Hilgenkamp, MESA Institute for Nanotechnology, University of Twente, The Netherlands
Yoshitaka Tateyama, WPI International Centre for Materials Nanoarchitectonics, NIMS
Qi-Kun Xue, WPI-AIMR & Department of Physics, Tsinghua University, P. R. China
Akira Ohtomo, IMR, Tohoku University (pending)
Max G. Lagally, WPI-AIMR, University of Wisconsin-Madison, USA
Yoshihiro Iwasa, IMR, Tohoku University (pending)Shuji Hasegawa, University of Tokyo (pending)
Yukio Hasegawa, University of Tokyo (pending)Taeghwan Hyeon, National Creative Research Initiative, Seoul National University, Korea
Takanori Fukushima, Functional Soft Matter Engineering Team, RIKEN
Hiroshi Jinnai, Kyoto Institute of Technology
Toshiharu Teranishi, Department of Chemistry, University of Tsukuba
Takashi Inoue, Department of Polymer Science and Engineering, Yamagata University
Kazushi Kinbara, IMRAM, Tohoku University, Japan
Tetsuro Higashi, Tokyo Electron Limited, Japan,
Ryutaro Maeda, AIST, Japan,
Youichi Sakakibara, AIST, Japan
Koji Ando, AIST, Japan31

Access
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Shinkansen Line
120min.

Car 40min. / 25km
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Shinkansen Line
20min.

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More information will follow in the coming months…

32

Appl. Phys. Lett. in press.
M. Kawasaki, T. Makino, and K. Ueno

“A highly-efficient UV sensor using conducting polymer/ZnO Schottky junction”
A wide gap semiconductor zinc oxide (ZnO) is one of the promising compounds for transparent oxide
electronics because its constituents are produced from abundantly deposited minerals. Elaborate
techniques of process and property control for ZnO allow us to develop further electrical applications.
The development of a solar-blind photo-sensor is the subject of tremendous investigation, in response to
the industrial demands in the fields of electronics, environmental sciences, and bio-technologies. Zincoxide, which is transparent to the visible light, is suitable for the purpose because the photon-electron
conversion efficiency is very high for ultraviolet (UV) light of the electromagnetic spectrum (below 400
nm in wavelength). In ZnO, their photo-created electrons are stored in the form of “charge-neutral”
states, so that an additional contacting layer (so-called a Schottky electrode) is indispensable to extract
these as current from the surface of ZnO.
In this news-letter, we report the high-performance
photo-sensor using a transparent conducting polymer,
poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate)(PEDOT:PSS) as a Schottky contact, which is compatible
to simple spin-coating process[1]. The chemical 2structureof PEDOT:PSS is shown in Fig. 1. The use of thetransparent organic contact is advantageous because theilluminated light is efficiently delivered to the active layerof the ZnO-based sensor without sizable loss at thecontacting layer. Besides, our ZnO photo-sensor can very
efficiently suppress the noise level, so that it can detect evenvery small flux at UV photons very sensitively, as werecharacterized by the external quantum efficiency (conversion
efficiency from photon to electron) as high as 100% in the UV

Fig. 1: Spectral response of the PEDOT:PSS/ZnO
photo-sensor at V=0 with its molecular structure in theinset. Also shown for comparison are the spectrum fora Si photo-sensor and a “100%-efficiency-line”.

region and a visible rejection ratio of 1000. Because of the low cost and easy-to-make process, thisdevice is promising for the application of UV light detection [2]. Work was conducted under thecollaboration with M. Nakano, A. Tsukazaki, A. Ohtomo, and T. Fukumura at IMR, Tohoku
Univ. and people in ROHM Corp.
References:[1] M. Nakano, et. al., Appl. Phys. Lett. 91, 142113 (2007)[2] M. Nakano, et. al., Appl. Phys. Lett. in press.

33

Proceedings of the National Academy of Science 2008
D. Pan, A. Inoue, T. Sakurai and M. W. Chen

“Experimental Characterization of Shear Transformation Zones for Plastic Flow of
Bulk Metallic Glasses”
The mechanical behavior of disorder solids, such as bulk metallic glasses (BMGs), has received
increasingly intense scientific and technological interests. Nevertheless, the underlying physical processesof dynamics and rheology of these solids are still poorly known. Recently, a cooperative shearing model(CSM) of STZs by Johnson and Samwer (Phys Rev Lett 95, 195501(2005)) has been shown to provide aneffective interpretation of low temperature plasticity in metallic glasses. In the Johnson-Samwer model, themechanical behavior of BMGs is intrinsically dependent on the actual volumes of STZs. Despite theintense theoretical and numerical efforts to identify STZ volumes of BMGs, an experimental quantitative
measurement of the STZ volumes is missing. In this work, we developed an experimental method tocharacterize the STZs of BMGs based on the Johnson-Sawmer CSM. The accordance between measured
STZ volumes and those predicted by theoretical analysis and MD simulations unambiguously demonstrates
that the plastic deformation of metallic glasses occurs upon cooperative shearing of unstable clusters of
atoms, instead of individual atom motion. The experiments presented herein pave a new way to gain aquantitative insight into the atomic-scale mechanisms of BMG mechanical behavior and the physicalprocesses in the dynamics and rheology of a plentiful variety of noncrystalline solids.
From the Johnson-Samwer CSM, we derived the STZ volume, Ω = kT / C ′mH , where k is Boltzmann
constant, T is temperature, C’ is a constant, m is strain rate sensistivity, H is hardness. In this study, six
BMGs (Pd40Ni40P20, Pt57.5Cu14.7Ni5.3P22.5, Cu60Hf25Ti15, Zr55Cu25Ni10Al10, Ni53Nb20Ti10Zr8Co6Cu3, and
Zr44Cu44Al6Ag6) were selected as model systems to represent a wide variety of chemical compositions,mechanical and physical properties in the BMG family. As shown in Figs. 1a and 1b, the mild ratedependence of hardness of BMGs was successfully measured by our rate-jump nanoindentation method.
Hence, the rate sensitivity is extracted for calculation of STZ volume. The determined STZ sizes of theselected BMGs vary from 2.5 to 6.6 nm3, or about 200-700 atoms. Strikingly, the measured STZ sizes inthis study agree well with those predicted by theoretical analysis and MD simulations, which clearly
demonstrates that the plastic yielding of metallic glasses occurs upon cooperative shearing of unstableclusters of atoms, viz. STZs, instead of individual atom motion under shear stresses. Moreover, ourexperiments demonstrated that the measured STZ volumes correlate well with Poisson’s ratio (Fig. 1c),suggesting an intrinsic relationship between BMG ductility and their atomic structures. ((PNAS) as an
Early Edition article)
Mingwei Chen (Email: mwchen@imr.tohoku.ac.jp)
8

100

(a)

0
0

500

1000

1500

Depth (nm)2000

Contact Pressure (GPa)

8
6

7
5

4
1500

2000

Depth (nm)

4
2
0

0

500

(b)
1000

1500

Depth (nm)2000

STZ Volume (nm3)

200

6

c
c
e
e c
e s
s
s
/
N
N /
N /
m m m
0
2 .
6 .
.
4
3
0 6
1
7
2

Force (mN)

300

Contact Pressure (GPa)

c
c
e c
e e
s
/ s
/ /
s
N
N
N
m m m
2 .
6 0
.
3
0 4
.
1
7
6
2

400

c
cc e
s
e
e
/
s/
sN
/
NN m
mm 0
.
2.
64
.
3
06
17 2

10

6

(c)

Pd40Ni40P20

Pt57.5Cu14.7Ni5.3P22.5

5

Cu60Hf25Ti15

4 Zr55Cu25Ni10Al10

BrittleNi53Nb20Ti10Zr8Co6Cu332

DuctileZr42Cu42Al6Ag6
0.25

0.30

0.35

0.40

0.45

0.50

Poisson's Ratio

Figure 1 (a) P-h curves at various loading rates by nanoindentation; (b) Corresponding H-h distributions of(a); (c) STZ volume correlation with ductility.

34

Akihisa Inoue

Commercialization of Fe-based Soft Magnetic Bulk Glassy Alloys
Recently, Inoue group developed new type of soft magnetic powder cores based on Fe-Nb-B-Si and
Fe-Nb-B-Si-P systems in collaboration with NEC TOKIN Corporation. The new magnetic powder cores
have been named as “SENNTIX” and exhibit the lowest core losses among all kinds of magnetic powdercores developed up to date. “SENNTIX-II” powder cores in Fe-Nb-B-Si-P system has enabled us toreduce more than 50 % core loss from existing metal powder and save thermal issue at personal
computer board, resulting in the significant extension of battery life time of Note Personal Computer.
Therefore, the “SENNTIX” powder cores have been supported as “Next Generation 2009 Reference
Design” by major power international corporation suppliers. As a result, the “SENNTIX” powder cores
have been produced on a large scale of several million pieces per month at NEC TOKIN factories inVietnam and China

35

Pictures of the commercialized TOKIN products developed by Inoue group36Dr. Peter V. Shusko’s University Research Fellowship (URF) of the Royal Society
The WPI-AIMR is pleased to announce that Dr. Peter V. Sushko, Associate Professor of
WPI-AIMR（p.sushko@ucl.ac.uk）has been awarded a prestigious University Research
Fellowship (URF) of the Royal Society, which is the UK National Academy of Sciences
established in 1660 (http://royalsociety.org).
The URF scheme “aims to provide outstanding scientists, who should have the potential
to become leaders in their chosen field, with the opportunity to build an independent
research career”. The Fellowship offers salary and research funds for a Fellow initially for
5 years followed by an extension for 3 years and, in exceptional circumstances, a further
extension for another 2 years.
The Royal Society URF is a highly competitive scheme of international standing. It is
opened to all citizens of the European Economic Area and Switzerland as wells as to all
those who obtained a PhD degree from the universities of these countries or worked there
as a researcher for at least two years. Approximately 30 Fellowships are awarded each year
in all fields of natural science including agriculture, computer science, mathematics,
physics, chemistry, biology, materials science, technology, medical, and engineeringsciences.
Dr. Sushko’s research project was awarded 0.5 M British pounds (¥100 M, $0.92 M)
over initial five years and it is one of 7 condensed matter physics and materials science
proposals supported in the 2007 call. He will work on computational studies of the electron
gas in quasi-two-dimensional systems including layered inorganic electrides andheterostructures of insulating oxides. The latter part correlates with and was inspired by theexperimental work carried out in the laboratory of Professor Kawasaki, WPI member.
Dr. Sushko will maintain his ties with the WPI-AIMR as Adjunct Associate Professor
and we would like to congratulate him and his advisor, Professor Alex Shluger, WPI-AIMR
Principal Investigator, with the award and wish them productive research in collaboration
with other WPI members in the years to come.

37

The results of the 2008 International Physics Olympiad
http://ipho2008.hnue.edu.vn/Competition/Results/
In the end of July, the 39th International Physics Olympiad was held in Hanoi, Vietnam, with 84 countries participated.
The results are tabulated below.
A few observations; 1) P. R. of China is usually number one for a number of years. 2) Among the western countries, USA andRussia are strong. 3) Quite a few students of USA, Canada, Australia teams are of Asian origin.

calculated by JSF

2008
Subject(Entry per country）
Total

Mathematics Gold
（６）
Silver535
BronzeGold
Chemistry
Silver（４）
Bronze257
GoldBiology
Silver(４)
Bronze220
PhysicsGold(５)Silver370
BronzeInformationGold(４)
Silver283
Bronze

The # of
JPN CHN KOR PRK TWN SGP THA AUS VNM IDN
medals

43
84
111
30
53
79
23
47
68
46
47
78
24
47
69

2
3
1

5
1

4
2

4

3

4
3
1
1
1
1
1
1
2

2
2
5
3
1

1
3
1
4
1
1
3

2
4

2
4
2
1
4
5
2
1
1

1
3
1
1
2
2
2
1
3
1
1
3

2
3
1
1
3
3
1
3
2
2
1
1

5
1
3
1
2
2

2
2
2
2
2
3
4

1
3
1
1
1

1
2
2

1
1
1
1
1
2
2
2
2
1
1

IND

IRN

1
5
6
3
1
1
2
1
4
1

1
2
1

ISR TUR KAZ USA CAN GBR FRA GER ITA RUS

1
2

3
1
2

1
2
3

4
2

1
2

2
2

4

1
3
4

1
3

1
2
1
1
1

2
2
5

1
4
1
2
2

3

3

The # of
JPN CHN KOR PRK TWN SGP THA AUS VNM IDN
medals

IND

2
2

2

2
4

4
2

1
4

1
3

2
2

1
3

2
2
1
2
2
1

3
1

3
1

4

4
1

1
2
3
1
3
1
1
2
1
1
3
1

3
2

1

2

6
3
3
4
2
2
2
2
1
2

1
3
3
1
1
2
2

2007
Subject(Entry per country）
Total

Mathematics Gold
(6)
Silver520
BronzeChemistryGold(4)
Silver256
BronzeBiologyGold(4)
Silver192
BronzePhysicsGold(5)Silver327
BronzeInformationGold(4)
Silver285
Bronze

39
83
131
31
58
72
20
43
54
37
46
51
25
48
72

2
4

4
2

2
4

4

3
1

2
3
1
2
2

4

2

4
4
1
3
2
2
1
1
1
1

5
2
2
4

4
1

2
3

4
2
2

2
1
2
2
2
1
1

2
1
2
1
2

1
3
2
1
3

3
3
1
2

2
2

1
1
2
2

1
2
2
1
3

1
3

1
2
2
1
1
1
1
3
1
2

3
2
1
1
1
3
2
2
1
2

IRN

1
3
2
1
1
1

ISR TUR KAZ USA CAN GBR FRA GER ITA RUS

3
1
1

2
3
1
3
1
4

4
2
2
1
1
2

2
3

1
3
1
1
2
2
2
2

4

2
1
1

1

1

3

2
1

2
2
2
1
1
1
1
1

1
3
1
2
2

1
3
1
3
1

1
1
3

4
1
2

1
2

1
1
3
1

5
2
1

2

2

5
1

2
2

3

3
1

2006
Subject(Entry per country）
Total

Mathematics Gold
(6)
Silver498
BronzeChemistryGold(4)
Silver255
BronzeBiologyGold(4)
Silver185
BronzePhysicsGold(5)Silver398
BronzeInformationGold(4)
Silver284
Bronze

The # of
JPN CHN KOR PRK TWN SGP THA AUS VNM IDN
medals

42
89
122
28
56
81
20
40
61
37
49
82
24
51
70

2
3
1
1
3

6
4
4

4
2

1
5

3
1

3
1

3
1

3
1

2
3
1
2
1
2
2

1
2
2
1
2
1
3
1

2
2
2
2
2

3

4
5

1
3
2
1

4

4
1
1
3

3
2
3
1

1
1
3
2

1
3

IND

IRN

3
3
1
3
2
2
4
1

5
1
2
1
3
1
2

2
2
3
1
1
4

4
1
3

3

38

2
2

ISR TUR KAZ USA CAN GBR FRA GER ITA RUS

3
1
1

2
2

1
2

2
4
3
1
2
2
4
1
1
3

3

1

3

3
2
1

1
1
2
1

5

2
3

2
2
2
2
1

2

1
2

5
1
1
2
1

4

2
2
2

3
1

1

1
3

2
2

3
3
3
1

1
2
2
2
3
4
3

3
1

2

2

1

External Research Grant List of Research Staff (As of September 1, 2008)(Unit: thousand yen)
Grant-in-aid for Scientific Research; "KAKENHI"
Scientific
Specially
Research on
Promoted
Priority
Research
Areas

Scientific
Research(S)

Scientific
Research(A)

Young
Scientists(A)

The Name of Researchers

Total

INOUE, Akihisa

131,853

3,000

LOUZGUINE, Dmitri V.

18,49016,800

TAKAHASHI, Takashi

68,500SOUMA, Seigo

12,090RICHARD, Pierre

1,651

1,651

KAWASAKI, Masashi

127,865900

ITAYA, Kingo

48,682

IKEDA, Susumu

2,080

2,080

390

390

KUZUME, Akiyoshi
YAMADA, Kazuyoshi

22,531TANIGAKI, Katsumi

47,900NOUCHI, Ryo

2,860

OHMI, Tadahiro

132,707

ESASHI, Masayoshi

89,281AKIYAMA, Kotone

4,250

YOSHIDA, Shinya

1,729

NAKAZAWA, Masataka

80,470MIYAZAKI, Terunobu

54,947TOKUYAMA, Michio

1,040

SHIMOMURA, Masatsugu

26,790ISHII, Daisuke

1,755

YAMAGUCHI, Masahiko

15,840YASUI, Yoshizumi

2,210

Others89,310

Joint
Research

Competitive
research funds
in Commissioned
Research(Excepted to
KAKENHI)39,5431,690
3,500

65,00065,000114,735

114,735

20,9923,000

10,821

8,910

12,09012,23027,690

1,700

4,040

2,000

41,200

3,970
3,900

2,500

300

2,860
108,160

24,54731,72042,221

2,300

15,340

1,950
1,729

80,47054,947
1,040
1,300

7,540

2,400

7,550

8,000

8,000

77,09942,12042,1201,755
14,040

1,800
2,210

ADSCHIRI, Tadafumi

164,589

MINAMI, Kimitaka

8,000

CHEN, Mingwei

1,100

1,100

FUJITA, Takeshi

3,250

3,250

NISHI, Toshio

1,690

NAKAJIMA, Ken

8,970

TSUKADA, Masaru

43,600HASHIZUME, Tomihiro

75,100

HIITOSUGI, Taro

19,600IKUHARA, Yuichi

24,041

18,200TSUKIMOTO, Susumu

3,000

3,000

SAITO, Mitsuhiro

1,716

1,716

SUSHKO, Peter V.

3,916

1,716

2,200

40,207

262,480

1,254,483

Commissioned
Research

45,370

8,000

1,690
8,970
35,0008,600
55,10020,00019,600190,330

124,840

5,300

182,440

44,43039

8,600

19,600541

21,060388,696

269,965

Inauguration of new journal “Nano Research”
Dr. Qikun Xue, WPI-AIMR Principal Investigator,

Cheung Kong Professor of Tsinghua

University, and academician of Chinese academy of Sciences, P.R. China, has founded a newjournal “Nano Research” and will run it as Editor-in-Chief together with Professor Hongjie Dai,
Stanford University. The monthly research journal is published by Springer.

40

Good luck!!!

Qiqun Xue, Tsinghua University, China

41

Research ProspectSurface Chemical Reactivities Modulated by Quantum Size EffectQi-Kun Xue a, b, c, Xucun Ma b, X. Chen a, Jinfeng Jia a, and Toshio Sakurai caDepartment of Physics, Tsinghua University, Beijing 100084, China
Institute of Physics, The Chinese Academy of Sciences, Beijing 100080, Chinac
The WPI Research Center Advanced Institute for Materials Research (WPI-AIMR)
Tohoku University, Sendai 980-8577, Japanb

Abstract
We report on a direct observation of a quantum reactivity with respect to the amountsof O2 adsorbed and the rates of surface oxidation as a function of film thickness on
ultrathin (2~6 nm) Pb mesas by scanning tunneling microscopy. Simultaneous
spectroscopic measurements on the electronic structures reveal a quantum oscillationthat originates from quantum well states of the mesas, as a generalization of the
Fabry-Pérot modes of confined electron waves. This quantum reactivity is further
confirmed by thickness-directed adsorption and self-assembly of cobalt phthalocyanine(CoPc) molecules. The work provides a novel approach for nanostructure tuning of
surface reactivities and rational design of heterogeneous catalysts.
1. Introduction
For a given solid, except for surface irregularities such as impurities and defects,
surface reactivity is often solely determined by its crystallographic orientation. At a
reduced size, however, particularly when the characteristic length scale enters thenanometer regime, the situation can change considerably from that of the bulk [1,2].
For example, in nature Au is the most stable metal, yet an Au nanoparticle becomeschemically reactive (when the size is ~3nm), and can catalyze the oxidation of CO [1].
Thin films are another such example where size-dependent surface chemical activities
have been observed, when the thickness is in the nanometer scale [3,4]. Such propertiesof nanostructured materials are usually attributed to the quantum size effects (QSE).
However, the materials used in most previous studies suffer from size fluctuation,
resulting in not well-defined material properties, and hence the evidences for the QSE
are at best qualitative [4]. In the case of thin films, a far more convincing proof of the
QSE would be the direct observation of an oscillatory dependence of the chemical
reactivities on the film thickness, which is reported here. Although bulk Pb is not a
catalyst, it may function as a catalyst at the reduced size, just like the Au [1]. More
importantly, a quantum modulation of the chemical reactivity is a general phenomenon,
reflecting the quantum size effect in the electronic states, which should not depend on45

any particular material.
Our Pb mesa samples were prepared on clean Si(111)-7×7 surfaces by the molecularbeam
epitaxy(MBE)
technique.
Semiconductor silicon was chosen as the (a)600nm x 600nm
substrate to achieve the required electronPbconfinement within the Pb mesas [5-8].
12
11
Figure 1a shows a typical scanning
14 13
15
tunneling microscopy (STM) image ofthe mesas. All mesas have flattop
geometry, presumably driven by surface
Sienergy minimization, but their bottom
extends laterally over several (typically 5(b)Si
to 10) atomic steps on the Si substrates.
Pb
For the mesa shown in Fig. 1a, five(d)consecutive thicknesses, 11 to 15 ML, arepresent. The high resolution STM images(Figs. 1c and 1d) clearly reveal that the
top surface is exclusively (111) and of (c)single domain, regardless of thickness
variation. Such a unique geometry
enables us simultaneously measure theelectronic structure, oxygen adsorption,and oxidation of the Pb films of different
thicknesses under identical experimental Figure 1. The Pb(111) mesa substrate used for
conditions.
this study. (a) STM image of a typical Pb mesa
Single crystal Pb is highly resistant to grown on the Si(111)-7×7 substrate, shown in aoxygen [9]: appreciable oxidation takes three-dimensional view. From right to left, theplace only at relatively high temperature thickness varies from 10 to 16 ML. (b) Two(≥370K) or at considerable oxygen dimensional view of the wedge shaped Pb
coverage at room temperature, which island. (c) Zoom-in STM image from (b)turns out to have destroyed the geometry showing the atomically flat nature of the Pbof the sample in Fig. 1a. To protect the mesa surface. The dotted line indicates the stepat the Pb/Si interface. (d) Atomic resolution
wedge-shaped mesas from possible STM image zoomed-in from (c) showing thatgeometry damage by high-temperature the Pb surfaces are (111)-oriented with a latticeannealing, we have developed a two-step constant of 0.35 nm. This kind of images could
approach: (i) low temperature (~100K) be obtained at any part of the mesa in Fig. 1(a).
O2 adsorption, followed by (ii) annealing All images were recorded at 80K with aat elevated temperatures to above 220K. tunneling current of 100pA.

46

2. Results and Discussion
Figure 2 shows the STM image of a mesa surface (the mesa is on the same Si
substrate and is nearby from the mesa shown in Fig. 1a) after 60L oxygen exposure at a
substrate temperature of ~100K. The image contains four different layer thicknesses (9to 12ML). The bright spots have a typical size of approximately 1.2 nm, and are
identified as chemisorbed oxygen clusters based on the scanning tunneling spectroscopy(STS) where a strong binding of the adsorbed clusters and the surface is observed[10,11]. Because the clusters are irregular both in size and shape, their exact chemical
nature is currently unknown. Despite that all the mesas are (111) oriented, here oxygen
adsorption exhibits a clear thickness dependence; the areal density of the adsorbed spots
on the even layers are always larger than that on the odd layers, while adsorption in thesame layer is essentially homogeneous. Figure 2a shows the thickness dependence of
the adsorbed oxygen (averaged over 10 samples). Except for an anomaly at 17ML,
which will be discussed later, a well-defined up-down oscillation with a period of 2ML
in the adsorbed oxygen coverage is immediately evident.
(a)

(b)
PbO

9ML
10ML
11ML

12ML

Figure 2. Thickness-dependent oscillatory adsorption of oxygen and oxidation. (a) STM image(339×339 nm2) of an oxygen adsorbed surface after 60L oxygen exposure at 100K. (b) STM
image (50×50 nm2) of the oxidized surface showing the formation of PbO monoxides at six(from 11ML to 16ML) thicknesses. The sample was first exposed to 60L oxygen exposure at
100K and then warmed up to room temperature with additional oxygen exposure of 120L. All
images were recorded at 80K with a tunneling current of 100pA.

Remarkably, an oscillatory behavior in surface oxidation (Fig. 2b) was observed,
when the samples were warmed up to room temperature with an additional oxygen
exposure of 120L to enhance the oxidation effect. Based on the anisotropic shape andlinear chain structure in high resolution STM images (not shown), the yellowish
rectangular islands in Fig. 2b are identified as massicot monoxides (PbO) [9].
Variable-temperature STM experiment reveals that the adsorbed oxygen clusters arestable up to 180K, above which the formation of the monoxide will take place. The

47

monoxide always develops from the previously existing oxygen clusters, and grows byforming depressed holes of one monolayer deep around these clusters, suggesting thatno significant diffusion of the adsorbed oxygen clusters had taken place, and that only
Pb atoms around the oxygen clusters were involved in the initial monoxide formation.
Surprisingly, if the same amount of oxygen was exposed to the surface at room
temperature, neither adsorbed oxygen nor surface oxides were observed, and the Pb
surface remains its intrinsic (111)-1×1 structure.
We have taken high-resolution STM images of the surfaces for all oxygen coverages
at the adsorption temperature, and separately at the observation temperatures after
annealing. The results indicate that localized electronic states associated with surface
steps and defects (most of which are dislocations) do not play any significant role ineither adsorption or oxidation. Strain is another factor to be considered, as epitaxial
strain could lead to different layer spacings along the normal direction of the film.
However, lattice relaxation usually takes place in the first a few layers near the Pb/Si
interface, while near the top surface layer spacing within the mesa is nearly the same asthat of bulk Pb [12,13]. Therefore, strain effect should not contribute significantly to thereactivity variation. Furthermore, if strain is indeed important, surface oxidation should
exhibit a monotonic, rather than an oscillatory, behavior with thickness. Note that, onbulk Pb(111) surfaces, such an oscillatory oxidation behavior does not exist. It can thus
be concluded that the film thickness is the deterministic factor for the variation of thesurface reactivity observed here.
One may speculate that surface kinetic process such as thickness-dependent diffusion
may play some important role in the oscillations. We measured the areal density ofoxides as a function of thickness (the black squares in Fig. 3a), and found that the
(a)

(b)

• oxygen clusters■ oxidesFigure 3. Correlation between the coverage of adsorbed oxygen and the LDOS. (a) The measured
adsorbed oxygen coverage (black dots for clusters and black squares for oxides) and the LDOS at
the Fermi energy (red triangles) as a function of the Pb film thickness at 100K. The oxygen
coverage is defined as the areal density of adsorbed clusters (oxides) on the surface of Pb islands,
measured as the integrated volume of these clusters (oxides) per surface unit area, assuming thatthe volume density of oxygen molecules are uniform and the same for different clusters. In thevolume measurement by STM, a spherical shape of clusters was assumed. (b) The calculated
LDOS at the Fermi energy as a function of the film thickness by first-principles method.

48

absolute ratio of the amounts of oxides is equal to that of the adsorbed oxygen clusters
almost for any two-adjacent-thicknesses (except for 17ML). For oxidation, someclusters have to diffuse and coalesce to form oxides while some decompose and desorb
from the surfaces. This observation suggests that the diffusion of oxygen species
involved in oxidation should not play a significant role in the oscillating oxidation
observed. We cannot rule out a possible column-crossing diffusion, but net flow of the
diffusing species should be small according to this measurement. Because of different
electronic structures (see Fig. 4a, to be discussed below), the boundary between theadjacent heights should behave like a “step”. If diffusion were important, either denuded
zones or preferential adsorption/reaction along the boundaries separating the even andodd layers, like that with usual surface steps and domain boundaries where diffusion
resulted structure decoration takes place as clearly observed on the single crystal Pb(111)
surface, should have been seen.
(a)

(b)

(c)

Figure 4. Measurements of the QWS and LWF. (a) A series of dI/dV curves showing theformation of QWS in the Pb mesas. The first QWS peak below and above the Fermi energy(located at zero bias) corresponds to the HOQWS and LUQWS, respectively. (b) Inverse of theenergy gap between HOQWS and LUQWS as a function of the Pb film thickness (from 6ML to43ML). (c) The measured QWS energy (with respect to the Fermi energy) and the LWF, as afunction of the film thickness. Open circles and filled squares are the LUQWS and HOQWS,
respectively, whereas the red dots are the LWF.

49

The observed oscillatory reactivity can be preliminarily attributed to the QSE [3,4].
When the thickness of a metal film is comparable to the wavelength (λF) of the electrons
at the Fermi energy (EF), the film can be treated as a Fabry-Pérot interferometer of theelectron de Broglie waves [15]. For Pb, λF =1.06nm, which is nearly 4 times of theinter-planar distance d0 along the crystallographic [111] direction. This coincidence (λF≈ 4d0) suggests that, when 1ML of Pb is added or removed, electron interference willchange from being constructive to destructive and vice versa, leading to a 2ML
modulation of the electronic structure [16-20]. More accurate analysis indicates that theexact period should be 1.8ML. The small difference between 2ML and 1.8ML results ina 9ML-beating mode on top of the finer 2ML oscillations. This explains the anomaly
observed at 17ML here and in previous studies [18,19]. The great resemblance between
QSE in chemical reactivity and QSE in physical transport properties [21-24] isunprecedented, suggesting a unified mechanism possibly originated from the uniquebehavior of the electrons at or within a small thermal energy window near the EF.
To further understand the oscillatory reactivity, we have measured the surface local
density of states at the EF [LDOS(EF)]. The LDOS(EF) as a function of the film
thickness is shown by the red triangles in Fig. 2a, in which a 2ML oscillation,
superimposed on a 9ML beating envelope, is clearly seen. The beating node appears at
17ML, and again at 26ML (not shown), in total agreement with that of the surface
chemical reactivity (shown by the black dots in Fig. 3a).
Figure 3b shows the thickness-dependent LDOS(EF) calculated by first-principles
method. Qualitatively speaking, experiment and theory are consistent with each other:both indicate an even/odd oscillation and the existence of a 9ML-beating mode. The
influence of the electronic structure on the chemical reactivity has been studied
theoretically before [25-29]. According to the simplest Newns-Anderson adsorption
model [26], as an oxygen molecule approaches the surface of the Pb (which can betreated as a free-electron-like metal), the anti-bonding Π∗ state of the O2 hybridizes withthe sp-band of the surface such that the Π∗ state broadens into a resonant state. Surface
one-electron image potential will shift this resonant state down in energy to below the
EF. This downshift and subsequent filling of the Π∗ state leads to the dissociative
adsorption. A lower LDOS(EF) implies that the Pb film has fewer electronic states to
respond, whereas a higher LDOS(EF) implies the film has more electronic states to
respond, to the presence of the oxygen. Therefore, a higher LDOS(EF) means a higher
probability in the above hybridization process, causing the Π∗ resonance to move tolower energies and to be occupied or, in other words, a higher surface reactivity.
Next, we discuss how the LDOS in a broader energy range would respond to thequantization of the electronic states. Figure 3a shows a series of dI/dV curves in theenergy range from −0.9eV to +1.50eV for thicknesses between 9ML and 21ML. The
results here reveal clearly the formation of well-defined quantum well states (QWS) in
the LDOS, namely, the sharp peaks in Fig. 4a, at every layer thickness. This can becompared to our previous photoemission study [19,23], in which the QWS was only
measured in the normal direction to the film surface. The distinctive sharp peaks here
are characteristic of the QWS at different quantum numbers. In Fig. 4a, the zero bias

50

corresponds to theEF. Thus, peaks closest to zero at negative and positive biases
correspond to the highest occupied QWS (HOQWS) and lowest unoccupied QWS(LUQWS), respectively. When the film thickness increases, the LUQWS peak moves
down to cross EF and becomes occupied for every two added layers, resulting in a 2ML
oscillation. The 17ML film is an exception for which the QWS resides right at EF. The
same was found again at 26ML and 35ML with a 9ML separation, which is nothing but
the long wavelength-beating mode discussed earlier. When fitting the inverse of theenergy gap (Δ) between the HOQWS and LUQWS, a good linear relationship between
1/Δ and film thickness is obtained, as shown in Fig. 4b [5,7].
Figure 4a further shows that an l ML thickness change can induce an appreciable shift
in the QWS energy, typically in the range of several hundreds of a meV, for example,
200 meV between 21ML and 22ML. Because of the large increase of the LDOS at the
QWS peak positions, for a given total number of states, the resulting QSE modulationon the electronic structure and hence surface reactivity could be quite significant.
The work function, which is the minimum energy required to emit an electron fromsurface to vacuum, is thought to be one of the most fundamental properties for surface
reactivity. Therefore, it was simultaneously measured here with the STM topographic
image [30,31]. The formation of the QWS also leads to an oscillatory local work
function (LWF), as shown by the red curve in Fig. 4c. The LWF varies in an energy
range between 3.5eV and 3.7eV with the same oscillatory behavior as the HOQWS
discussed above: the closer the HOQWS is to the Fermi energy, the smaller the value ofthe LWF is. This is reasonable because the LWF was measured at a negative sample bias,
at which electrons tunneling from HOQWS to the tip usually dominate the current [17].
The above results suggest that an electronic state of the Pb mesa is very muchconfined to a region of the same thickness, such that the Fabry-Pérot interference of theelectron wave can provide a characteristic fingerprint of that thickness [32].
As for the relationship between LWF and QWS, it comes mainly from the spatial
distribution of the QWS electrons near the surface. Based on the density functional
theory calculations, we find that the decay of the electronic state normal to the surface ismuch slower than others. For the latter, although they may be closer to EF, their spatial
distributions are much more localized. Because the magnitude of the electron density
above the surface is decisive to the tunneling current and hence to the measurement of
the LWF, the LWF is predominantly determined by states close to the Brillouin zone
center with well-defined QWS.
To examine whether this oscillation behavior is limited only to oxygen, we carried out
experiment using very different molecules of cobalt phthalocyanine (CoPc) [33]. The
result is shown in Fig. 5. In this case, the thickness-dependent adsorption behavior iseven much more obvious; all CoPc molecules diffuse long enough and could reach theenergetically favorable regions (12, 14, 17 and 19ML) where stronger oxygen
adsorption and oxidation were always observed, to form an ordered self-assembled
monolayer, leaving other regions (11, 13, 15, 16 and 18ML) intact (Fig. 5b). With this51

experiment,theinfluence
thickness-dependent diffusion
can safely be ruled out.
Moreover, here there is nodifficulty in identifying theadsorbed species, the individual
CoPc molecules are clearly
resolved and identified in thehigh resolution STM image in
Fig. 5c.
3. Conclusion

(a)

(c)

Pb

(b)
Si

(d)

By synthesizing flat-top Pb
mesas on Si(111) substrate, theoscillatory surface reactivity due
to quantum size effect iscobalt (II) phthalocyanine (CoPc)
unambiguously demonstrated for
Figure 5. Thickness-dependent oscillating adsorption
the first time by using a two-step and self-assembly of CoPc molecules on Pb(111) mesa.
oxygenadsorption/annealing (a) STM image (700×700 nm2) after 0.45ML CoPc
method. Our in-depth study molecules were deposited on the Pb mesa surface. (b)further provides quantitative STM image (0.5V and 100pA, 200×200 nm2) zoomed
accounts of the correlations from (a) showing the selective preferential adsorption of
between the quantum surface CoPc molecules at 12ML and 14ML. Note thatreactivity, the QSE, the surface molecules are completely missing at 11ML, 13ML and
15ML, where bare Pb surface is present. (c) STM image
local density of states, and the (-0.2V and 98pA, 11×11nm2) showing the structure of
local work function. We expect CoPc molecules and the self-assembled monolayer
the quantum surface reactivity to formed on the Pb(111) surface. (d) The schematic
be a general phenomenon illustration of the CoPc molecule.
beyond just Pb and hence has
broad applications such as modifying the surface chemistry of metals and to serve as a
guide to nano tailoring metal catalysts.
Acknowledgements
The work was carried out in collaboration with Peng Jiang, Yun Qi, Yu Yang, Wenhui
Duan, Wei-Xue Li, Xinhe Bao and S. B. Zhang. We thank Shuai-Hua Ji, Ying-Shuang
Fu, and Quan-Tong Shen for technical assistance in the experiment. Some STM images
were processed by using the WSxM software. This work was supported by National
Science Foundation and Ministry of Science and Technology of China.

52

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54

Theory of Scanning Probe Microscopy and Electron Transport inNano-Structures
M. Tsukada
WPI Advanced Institute for Materials Research, Tohoku University,
Katahira 2-1-1, Aobak-ku, Sendai 980-8577, Japan andGraduate School of Advanced Science and Technology, Waseda University
Shinjyuku-ku, Tsurumaki, Tokyo 162-0041, Japan
1. Introduction
Recent progress of nano-technology has been remarkable and much expectation has
been arisen for further epoch making developments, but this would be only possible
with strong cooperation of basic science and technology, cooperation among different
disciplines, that between experiment and theory. Theory really plays an important rolefor predicting novel functions of nano-structures and make useful proposals ofdesigning and fabricating such systems from the atomic scale.
Scanning Probe Microscopy (SPM) is a family of powerful experimental methods toobserve the atomic scale structure and properties of nano-scale materials[1,2] and used
as a tool of atom manipulation[3]. In spite of profound information that SPM can inprinciple provide, it is not quite easy to analyze experimental data without a support
from theoretical simulation[4]. This is because the measured quantities by SPM are
obtained by a rather strong or subtle atomic scale local interaction between the tip andthe sample[5]. In the following sections, some topics will be introduced from results
obtained by Project of “Development of Versatile Scanning Probe Simulator”
supported by JST from October 2004 to March 2008 conducted by author’s group.
We also discuss some topics of the quantum transport through molecules connected
to metallic electrodes. Remarkable natures of coherent electron transport are predicted
including the nature of the resonant tunneling via molecular levels and a large loop
current induced by the source-drain current. With the coupling of the electron motion
to the molecular vibrations or electro-magnetic environment, dissipative or hoppingtransport becomes prevailing. Transition from the coherent to dissipative regime is also
discussed.

55

2 Models of the tip
We have developed a software which
can generate large scale atomistic
models of the tip as well as its coarse
grained continuum model in a computer.
Various structures of the tip limited by
facets can be formed from the crystal
atomic structure freely so as to minimize
the surface energy of the tip using a
convenient GUI (Graphycal User
Interface). Reconstruction of the top
most atoms can be made with evaluating
the total surface energy of the tip.

(a)

Figure 1. A GUI frame for designing the
tip atomic structure by cutting facets
manually by the right bars.

(c)

(b)

Figure 2. (a) Structure, (b) simulated and (c)experimental AFM image of MSTBPP.

3. Simulation of AFM images
With use of the hydrogen atom tip, the AFM image of methylthiophenyl-tris- tbuthyl phenyl-porphyrin (MSTBPP) is simulated. As seen in Fig.2, the theoreticalimage reproduces the experimental observation fairly well[6]. In this simulation, themolecular shape and position are fixed. However, if they are allowed to deform by astrong repulsive force by the tip, regular images are gradually lost, and we observe aninteresting deformation behavior of the sample molecule.
Fig.3 (a) and (b) are the simulated frequency shift image and the dissipation imageof the chemisorbed methyl group on a hydrogenated Si(100) dimmer surface,respectively[7]. The model of the tip used is Si4H9 cluster model. The angle of the56bond connecting the methyl to the Si atom is easily bent by a repulsive force by the tip.
Therefore the image is rather vague and hydrogen atom can be observed only as a dark
crescent area. The dissipation image produces a rather sharp shape but the analysis isdifficult without theoretical simulation.
(a)

(b)

Figure 3. NcAFM image of methyl group chemisorbed on the dimer Si atom of hydrogenatedSi(100) surface taken by the frequency shift (a) and the dissipated energy (b).

4. Theory of SPM in water
There are several difficult problems for the simulation of dynamic AFM in liquids.
First, the cantilever bending oscillation as a flexible elastic body should be solved
simultaneously with fluid dynamics as shown in Fig.4. Fig.5 shows a resonace curve ofrectangular silicon slab cantilever in water. We can see that the resonant frequency is

Tilt angle (rad)

water

vacuu
air
Frequency (kHz)

Figure 4. Oscillation of cantilever in water. Figure 5. Resonant curves of the thin Si
rectangular cantilever in water, air and in vacuum.

lowered by about 1/5, and the width of the resonance is enlarged by the order of 103. It
is remarkable that the amplitude of the bending angle of the tip apex does not decay somuch at the higher frequency side, which reproduces the experimental features.

57

When a tip approaches to the sample, it feels the force mediated by water molecules.
This effect to the cantilever motion determines the AFM image in liquids. Fig.6 shows
the three-dimensional force map of the CNT(carbon nano-tube) tip over a mica surface
in water. It can be seen that the oscillatory solvation force develops near the surface,but its phase sensitively depends on the lateral position of the tip. The oscillatory
solvation force is caused by the layer-like distribution of water molecules near the
sample and the tip surfaces as seen in Fig. 6(b).
(a)

(b)

Figure 6. (a)The 3D force map of mica by CNT tip and (b) The layer structure of the
distribution of water molecules near the tip and mica.

5. SPM simulation for protein molecules
Mechanical deformation and stress effect on various physical and chemical propertiesof proteins provide rich information on the functionality of protein molecules, which canbe elucidated by the theoretical simulation [8]. Not only AFM images, but also the tip
force-distance curve reveal important structural,mechanical, chemical properties of protein molecules,
and the interpretation of these are major target of thesimulation.
As an example, a constant force AFM image of asingle fragment collagen molecule adsorbed on agraphite substrate is calculated both under ultra highvacuum and in a wet condition[9]. As the tip model for
Figure 7. The simulation model
this simulation, a narrow capped carbon nano-tube is of CNT tip and the callagenadopted as shown in Fig.7. The effect of the water sample immersed in water.
molecules on the tip-sample interaction force immersing the collagen has been also
investigated.

58

The image of Fig. 8 shows a nodal structure, which reflects the triple helix structureof the collagen. In the case of the system immersed in water the amplitude and phaseof the oscillatory solvation force isdifferent between on top of thecollagen molecule and on top of thegraphite surface, which requires
careful analyses of the image [8].
Green fluorescent protein (GFP)
emits green fluorescent light when Figure 8. The simulated constant force mode AFM
of a short collagen model.
illuminated with blue light. It has
been found that the fluorescent activity of the chromophore, which is located at thehydrophobic cavity inside the β-barrel structure, is remarkably suppressed on thecompression by the tip. We performed the simulation of the compression process of
the GFP by the all-atom molecular mechanics with a hybrid ONIOM9 (QM/QM)
calculation [9]. Upon compression the hydrogen bond network around thechromophore is broken, and the potential barrier for the conformation change
disappears opening a non-radiative reaction pathway, which causes the quenching of
the fluorescence.
Potential Energy Surface
Inner rotation

Figure 9. Cpmpression of GFP and associated change of the potential energy surface of excited(dashed line) and ground state (full line).

6. Coherent transport through molecular bridges
The transport through molecular bridges is strongly influenced by the connecting
part to the electrodes. An example has been found in the tape-porphyrin molecules[10].
Tape porphyrin is a sort of the oligomer of the porphyrin, which shows the vanishingof the HOMO-LUMO gap for a very long chain length. We investigated four different
linkage structures of the tape-porphyrin to the gold electrodes as shown in Fig.10. For
all the cases, the numbers of the porphyrin molecules in the chain is assumed to be59

eight (n=6). The calculated results of the transmission spectra are shown in Fig.11. It isremarkable that only a small difference of the linkage part dramatically influences the
conductance of the molecular bridge. Namely among the four bridges from A throughBias window

n=6

Figure 11. Electron transmission spectra for
the four different linkage structure of Fig.10
to the Au electrodes.

Figure 10. Four different likage structuresof the tape porphyrin to the gold electrode.

D shown in Fig.10, the case B shows the largest conductance, because there is
prominent transmission peak very close to the Au electrode Fermi level.
The internal current distribution within the molecule, which is induced by thesource-drain current, also shows remarkable quantum nature. Namely, when theelectron incident energy is close to a degenerate molecular level, a large loop current isoften generated inside the molecule[11].
Figure 12(a) illustrates internal current in a triangular nano-graphene sheet boundwith zigzag edges. The connection to the source-drain electrode is made by the vinylgroup to the atoms at the same zigzag edge[12]. The electron incident energy is set as
E = −0.165t . Noticeably, a large current loop appears circulating a large area of thegraphene molecule. Figure 12(b) schematically illustrates the orientation of the current
flow, which is reversed by changing the bias polarity. The strength of the current is bymore than ten times larger than the source-drain current. Interestingly enough, thesame carrent distribution appears for the the isolated molecule under a static magnetic
field. One might speculate a close relationship between the source-drain induced loop
current and the molecular diamagnetic current and nano-scopic persistent current
induced by magnetific field.

60

(a)

Source(b)

Drain

Figure12. (a)Current distribution in side
the triangular grapheme (total atom
number is 4353) for the electron with theenergy E=-0.16t (t is the hopping integral
between the nearest neighbor). (b) A
schematic view of the current distribution.

7. Effect of coupling to the outer environment
Since the electron number in a molecule and the phase of the electron wave-function
aremutually conjugate physical quantities, there is an uncertainty relation between
the two. If the bottleneck at the connection part between the molecule and theelectrodes is weak, the phase tends to be a good quantum number, and a coherent
quantum transport throughout the whole system described above is expected. However,if the bottleneck is strong, the electron number in the molecule tends to be a moredefined quantum quantity. In this case the electron transfer is associated with theenergy dissipation to the outer environment as molecular vibration or theelectro-magnetic field. Then the dissipative electron(hole) hopping transition becomesdominant and the Coulomb blockade or “Polaron blockade” phenomena emerges aswill be seen in the I-V characteristics as shown schematically in Fig.13. In Fig.13 EC

is the order of the blockade energy determined by the effective capacitance C

I
Excitation of electro-magnetic fieldEC =Excitation of molecular vibration

e
2C

ηλ2
λ hω λEC = ¦

ECeV

coherent within a molecule

Figure 13. Dissipation processes of the electron transition between the electrode and the molecule(right), and associated Coulome or Polaron blockade effect on the I-V curve.

61( EC =2e2
) or the coupling energy to the molecular vibration ( EC = ∑ ηλ ) where2C
λ hω ληλ , ω λ are electron-vibration coupling energy and the eigen frequency of the mode λ ,respectively.
With the decrease of the transfer integral inside the molecular region, the electronic
state changes from the extended state to a polaron like localized state. By considering
the transition over the polaron-like states, the carrier transfer in the molecular chain
bridge can be properly analyzed. The model we analyzed (Fig.14) consists of a chainof thiophene molecules and two outer electrodes.
Electrode

Electrode
Structure change
Energy dissipation
Loss of the coherence

tunnelingionization

Figure 14. A schematic view of the molecular chain bridge
Mostly coherent
MO likeTime dependenceof occupation

Pseudopolaron

Figure 15. Time dependence of the electron occupation at each site after injection Hopping
integral for left 0.2eV, for right o.5eV.

Figures 15(left) and (right) show the time-dependent occupation of each site after
injection. The 0th and 9th site mean the left and the right electrode, respectively[13].
After a short passage time, the occupation at the left electrode rapidly decreases andthe right electrode increases. If the bare hopping integral V is relatively weak(0.2eV,
the left case of Fig.15), the eigen-states relevant to the transition are more or lesscomposed by a dressed states and the electron mobility is considerably slowed down
compared with the case of the stronger bare hopping integral(0.5eV, the right case of
Fig.15). For bulk organic materials, time-of-flight (TOF) experiments are frequently

62

used to estimate the carrier mobility. The result of the mobility in Fig.15 roughly
reproduces the behavior observed by TOF.
8. References[1] R.Wiesendanger, J.Guentherodt (eds.): Scanning Tunneling Microscopy I,II,III(Springer, 1996).
[2] S.Morita, R.Wiesendanger and E.Meyer (eds), Noncontact Atomic ForceMicroscopy, (Springer, 2002)[3] Y.Sugimoto, M.Abe, S.Hirayama, N.Oyabu, OCustance and S.Morita, Nature
Materials, 4 (2005) 156.
[4] M.Tsukada,K.Kobayashi, N.Isshiki and H.Kageshima, Surface Sci. Rept., 33(1991)
265.
[5] M.Tsukada, N.Sasaki, M.Gauthier, K.Tagami and S.Watanabe, in Non-Contact
Atomic Force Microscopy, eds. S.Morita et al, Springer 2002, pp257-278[6] M.Harada and M.Tsukada, e-J. Surf. Sci. and Nanotechnol., in pres.
[7]A.Masago and, S.Watanabe, K.Tagami and M.Tsukada, J. Phys. Conf. Ser. 61(2007) 1122.
[8] L929K.Tagami and M.Tsukada, e-J. Surf. Sci. and Nanotechnol. 4 (2006) 294.
[9] Q.Gao,K.Tagami, M.Fujihira and M.Tsukada, Jpn. J. Appl. Phys. 45 (2006).
[10] K.Tagami and M.Tsukada, e-J. Surf. Sci. and Nanotechnol. 1 (2003) 45.
[11] M.Tsukada, K.Tagami, K.Hirose and N.Kobayashi, J.Phys. Soc.Jpn., 74(2005)1079.
[12] K.Tagami and M.Tsukada, e-J.Surf. Sci. and Nanotechnol. 2 (2004) 205.
[13] K.Mitsutake and M.Tsukada, e-J. Surf. Sci. and Nanotechnol. 4 (2006) 311.

63

Nanostructured Assembly at Solid Surfaces and Nanomaterials in Energy
and Environment Application
Li-Jun Wan
Institute of Chemistry, Chinese Academy of Sciences,
Beijing 100190, China, wanlijun@iccas.ac.cn

1. Introduction
Nanostructured self-assembly with organic molecules is increasingly realized as afeasible bottom-up route for the fabrication of molecule-based devices in the future [1].
So far, various sophisticated architectures have been achieved in ambient or UHV
environments by using the non-covalent interactions, including van der Waals
interactions, H-bonds, and π-π interactions [2,3]. From a fundamental point of view, theinvestigation on the organic molecules adsorption at the solid/liquid interface will be
helpful in understanding the intermolecular interaction and molecule surface moleculesurface interaction and how they determine the formation of self-assembled orderedstructures. The information is of great value to guide the construction of self-assembly
structures on the surface. The adsorption of organic adsorbates is closely related to theelectrocatalysis, electrochemical reaction, photovoltaic applications, and many others.
On the other hand, nanostructure materials are attracted interests in energy andenvironment application. In this paper, we briefly report our recent progress in both
surface assembly fabrication and nanomaterial preparation.
2. Metallamacrocyclic Supramolecular Assemblies
Among various building blocks, the metallamacrocyclic supramolecular assemblies
represent a class of interesting materials not only bearing a beautiful topologicalstructure but also possessing magnetic, photophysical, electronic, and redox properties
that may not be accessible from purely organic systems [4,5]. Fabricating desirable andstable devices from these assemblies on solid surfaces and understanding the rules
governing their self-organization on solid supports are significant fundamental steps
toward realizing useful nanodevices and nanostructures.
The rectangle [(1,8-bis(trans-Pt(PEt3)2)-anthracene)(4,4’-bpy)]2(PF6)4 is found toform a highly ordered molecular adlayer, as shown in Figure 1a. The adlayer has arectangular unit cell of (7×3√3) structure. As revealed by high-resolution STM images(Figure 1b), each molecule consists of a set of four bright spots, which correspond to
the aromatic rings of the supramolecular rectangle, with dimensions of 2.0 nm × 1.2 nm,
consistent with the size of the rectangle determined from single-crystal X-ray
crystallography [6]. The supramolecular rectangle adopts a flat-lying configuration on
the Au(111) surface, and a dark depression is seen in the center of each rectangle.
Similar to the supramolecular rectangle, two other supramolecular assemblies withsquare and cage shapes are found to form an ordered adlayer on Au(111) as well [7].

65However, these supramolecular assemblies cannot form an ordered stable adlayer on the
HOPG surface, which is mainly due to the weak interaction between molecules and the
HOPG surface. When mixing the rectangle and cage supramolecules together, they tend
to separate to form individual domains on the surface.

Figure 1. (a) Large-scale and (b) high-resolution STM images of the self-assembled
supramolecular rectangles adsorbed on a Au(111) surface. Underlying Au(111)-(1 × 1) lattice isshown inset. (c) Proposed structural model for the adlayer.

3. Ordered Calixarene/fullerene Array
Fullerene self-organization is receiving increased attention due to the possibility tointegrate molecules with different functions and to fabricate novel nanostructures.
Moreover, to construct an ordered array of fullerene is very important for device
fabrication based on fullerene, owning to its unique physical and chemical properties
and myriad potential applications [8,9]. By taking advantage of the host-guest
interaction between calixarene and fullerene, an ordered fullerene array is obtained on
Au(111) [10].
Figure 2a is a typical STM image of the adlayer of a calix[8]arene derivative(OBOCMC8) on the Au(111) surface in 0.1 M HClO4. The molecular adlayer consistsof regular rows of round shaped calix-like features with dark depressions in the center.

66

The distance between the centers of the dark depressions is 1.2 ± 0.1 nm along the A
direction and 1.7 ± 0.1 nm along the B direction. The molecular rows in the A and B
directions cross each other at an angle of 95 ± 2°. The dimension of round protrusion
matches well with the size of the OBOCMC8 molecule and, therefore, each calix-likefeature appearing in the STM image can be assigned as an individual OBOCMC8
molecule. In the structural model, each molecule is adsorbed on the surface in an
upright configuration through the carboxyl-gold interaction. The surrounding
protrusions and the dark depressions of calices in the STM images are attributed to thephenyl groups and the molecular cavity, respectively.
A typical STM image of the adlayer of a C60/OBOCMC8 complex on the Au(111)
surface is shown in Figure 3a. An interesting feature of the C60/OBOCMC8 adlayer isthe well-ordered bright spots, which appear to fill the dark depressions that wereobserved in the OBOCMC8 adlayer, presumably due to the inclusion of C60 molecules.
(a)(b)

Figure 2. (a) Height-shaded surface plot of a high-resolution STM image of the OBOCMC8
adlayer on Au(111). (b) Proposed structural model. The biased voltage and tunneling current
were -213 mV and 670 pA, respectively.

(a)

(b)

Figure 3. (a) Height-shaded surface plot of a high-resolution STM image of the C60/OBOCMC8
adlayer on Au(111). (b) Proposed structural model. The biased voltage and tunneling current
were -140 mV and 1.0 nA, respectively.

67

The inter-distance of bright spots along the molecular rows is measured to be 1.4 ± 0.1
nm, which is approximately the size of the C60/OBOCMC8 complex. The individualbright spots are surrounded by circular protrusions. As shown previously, theC60/OBOCMC8 complex tends to be in the upright configuration on the Au(111)
surface bonded through the carboxyl groups. Therefore, the bright spot and circular
protrusion can be assigned as C60 and phenyl units, respectively, with each OBOCMC8
cavity filled with a C60 molecule.
The same strategy could be used to assemble other fullerene derivatives, clusters, andorganic molecules. The so-obtained architecture with stable configuration andwell-defined array should be interested in nanodevice and sensor applications.
4. Nanostructured materials and their applications
4.1 Pt hollow nanospheres.
Considerable attention has been paid to alternative energy sources such as hydrogenand fuel cells as energy sources in an attempt to relieve the pollution and energy crisis.
Among various candidates, Pt has stimulated considerable research into its use [11].
However, a critical problem with Pt-based catalysts is their prohibitive cost. Hollow
metallic nanospheres exhibit catalytic activities different from their solid counterparts
with the advantages of low density, saving of material, and reduction of costs.
The Pt hollow nanospheres issynthesized via the replacement
reaction between Co nanoparticles
and H2PtCl6 [12]. As thisreplacement
reaction
occursrapidly, the Pt atoms nucleate andgrow into very small particles,
eventually evolving into a thinshellaroundthecobaltnanoparticles. Figure 4a is a
Figure 4. (a) and (b) TEM images of Pt hollow
typical large-scale TEM image. It
nanospheres.
was found that the centers of thespheres are brighter than the edges. The individual Pt spheres (Figure 4b) are composedof an empty core with a shell, that is, a hollow structure. The thickness of the shell is ~2
nm. The diameter of the nanospheres was statistically calculated to be 24 ± 2 nm. The
shells of the Pt hollow nanospheres seem to be rough and consist of Pt nanoparticles
with a size of ~2 nm. Another feature is that the shell is incomplete and porous, notsolid. This feature endows the Pt hollow nanospheres with a high surface area.
The electrocatalytic activity of the Pt hollow nanospheres for the oxidation of
methanol is demonstrated and compared with that of solid Pt nanoclusters by using awell-used electrochemical reaction in H2SO4 [13]. From the CVs in Figure 5, both the
Pt hollow nanospheres and nanoclusters show catalytic behavior for theelectro-oxidation of methanol by the appearance of an oxidation current in the positive
potential region. The onset potentials are around 0.3 V vs. SCE. The peak potentials for68the oxidation of methanol are approximately 0.65 V vs. SCE, in good agreement withthe literature values. The remarkably high oxidation current for the hollow-spherecatalysts is directly related to the high surface area. Since the Pt hollow nanospheres arecoreless, a larger number of Pt
nanospheres
were
obtained
relative to that found with thesame loading of solid Pt
nanoclusters. The incomplete
shell of hollow nanospheres may
also provide the interior surface
for the catalytic reaction.
Assuming that the inner andouter surfaces of a hollow
nanosphere can participate in the
catalytic reaction, the surface
area of the single hollow
Figure 5. CVs of Pt solid nanoclusters (dashed line)
nanosphere is ~ 1.16 times as thatand hollow nanospheres (solid line) on a glassof a single solid nanocluster. The
carbon disk electrode in H2SO4 (0.5 M) andhigher surface area of Pt
methanol (0.6 M). The same loading of nanospheresnanospheres results in a higher
and solid nanoclusters was applied to the electrodes
catalytic activity.
(0.0175 mgcm-2). Scan rate=50 mVs-1.
4.2 ZnS nanoporous nanoparticles (NPNPs)
Environmental problems associated with organic pollutants and toxic water pollutants
provide the impetus for sustained fundamental and applied research in theenvironmental remediation. Semiconductor photocatalysis offers the potential forcomplete elimination of toxic chemicals through its efficiency and potentially broad
applicability [14]. An important application of ZnS is as a photocatalyst inenvironmental protection through the removal of organic pollutants and toxic waterpollutants. However, the development of cost-effective methods suitable for thelarge-scale synthesis of ZnS nanoporous nanostructures with high catalytic activity andeasy separation represents a critical challenge to their practical applications.
ZnS NPNPs were prepared by a facile solution-phase thermal decomposition routein the presence of poly(N-vinyl-2-pyrrolidone) (PVP) [15]. Figure 6a shows a typical
TEM image of a ZnS sample, revealing a large number of well-dispersed spherical
nanoparticles with uniform size and shape. The average size of these particles is about
60 nm. The high-magnification TEM image in Figure 6c shows many spots with a clear
contrast difference in each individual nanoparticle, indicating that the NPNPs consist ofsmaller nanoclusters (NCs) with a size of 3–5 nm which are assembled in a nanoporous
structural configuration. A selected-area electron diffraction (ED) pattern of ZnSNPNPs is presented in the inset of Figure 6c. The ED pattern shows a set of concentricrings instead of sharp spots as a result of the small crystallites. A representative
high-resolution TEM (HRTEM) image of ZnS NPNPs in Figure 1d, with an inset image69

taken on the outside of the particles, shows the lattice fringes of nanocrystals in
nanoparticles with a spacing of 0.31 nm, which corresponds to an interplanar distanceof the (002) plane of hexagonal ZnS.

Figure 6. (a) Low-magnification TEM image, (b) SEM image, (c) high magnification TEM
image, and (d) HRTEM image of ZnS NPNPs. The inset in (c) is the electron diffraction pattern.
The inset in (d) shows the enlarged lattice fringes.

The photocatalytic activity of theZnS NPNPs was investigated incomparison with those of ZnS NCs
prepared by a literature method and of
a commercial photocatalyst (Degussa
P25 titania), with the photocatalytic
degradation of eosin B as a test
reaction. The characteristic absorptionof eosin B at 517 nm was chosen as
the monitored parameter for thephotocatalytic degradation process.
Figure 7 shows the absorption
spectrum of an aqueous solution ofeosin B (initial concentration: 5.0 ×
Figure 7. Absorption spectrum of a solution of
10－5 M, 30 mL) in the presence of eosin B (5.0 ×10－5 M, 30 mL) in the presence ofZnS NPNPs (10 mg) under exposure to ZnS NPNPs (10 mg) under exposure to UV light.

70

UV light for various durations. The absorption peaks corresponding to the eosin B
molecule, such as the sharp peak at 517 nm, diminish gradually as the exposure timeincreases and completely disappear after about 40 minutes. No new absorption bands
appear in either the visible or ultraviolet regions, which indicate the complete
photodegradation of eosin B. The color-change sequence in the sample during thisprocess is shown in the inset of Figure 7, from which it is clear that the intense pinkcolor of the starting solution gradually disappears with increasingly longer exposure
times.
5. Summary
Innovative assemblies with designable structures have been achieved on the surface
either by tuning intermolecular interactions, such as H-bonding, van der Waals
interactions, π-π interactions, or electrode/molecule interactions. The active role ofpotential at the electrochemical solid/liquid interface adds another dimension of control
over the orientation of molecules or the organization of the surface assembly on thesurface. This perplexing but also fascinating feature of electrochemical adlayer may
open new horizons for the development of new functional elements in future sensor anddevice design. In addition, tailored surface structures on the surface afford the highly
efficient, controllable reactions on the surface. It is reasonable to believe that newheights for the building of complex architectures with specific structures and functions
will be achieved in future.
6. References[1] J. V. Barth, G. Costantini and K. Kern, Nature, 437 ( 2005) 671-679.
[2] L.-J. Wan, Acc. Chem. Res.,39 ( 2006) 334-342; D. Wang and L.-J. Wan, J. Phys.
Chem. C, 111 (2007) 16109-16130.
[3] S. De Feyter and F. C. De Schryver, J. Phys. Chem. B, 109 ( 2005) 4290-4302.
[4] P. F. H. Schwab, M. D. Levin, and J. Michl, Chem. Rev., 99 (1999) 1863-1933.
[5] M. Fujita, Chem. Soc. Rev., 27 (1998) 417-425.
[6] C. J. Kuehl, D. H. Songping and P. J. Stang, J. Am. Chem. Soc., 123 (2001)
9634-9641.
[7] Q.-H. Yuan, L.-J. Wan, H. Jude and P. J. Stang, J. Am. Chem. Soc., 127 (2005)
16279-16286.
[8] R. F. Curl, Angew. Chem., Int. Ed. Engl., 36 (1997) 1566-1576.
[9] H. Kroto, Angew. Chem., Int. Ed. Engl., 36 (1997) 1578-1593.
[10] G. B. Pan, J. M. Liu, H. M. Zhang, L.-J. Wan and C. -L. Bai, Angew. Chem. Int.
Ed., 42 (2003) 2747-2751.
[11] A. T. Bell, Science, 299 (2003) 1688 - 169.
[12] H.-P. Liang, H.-M. Zhang, J.-S. Hu, Y.-G. Guo, L.-J. Wan and C.-L. Bai, Angew.
Chem. Int. Ed., 43 (2004) 1540 - 1543.
[13] T. Hyeon, S. Han, Y.-E. Sung, K.-W. Park and Y.-W. Kim, Angew. Chem., 115(2003) 4488 - 4492; Angew.Chem. Int. Ed., 42 (2003) 4352 - 4356.

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[14] M. R. Hoffmann, S. T. Martin, W. Choi and D. W. Bahnemann, Chem. Rev., 95(1995) 69 - 96.
[15] J.-S. Hu, L.-L. Ren, Y.-G. Guo, H.-P. Liang, A.-M. Cao, L.-J. Wan and C. -L. Bai,
Angew. Chem. Int. Ed., 44 (2005) 1269 -.1273.

72

Supercritical Hydrothermal Synthesis of Organic-Inorganic Hybrid
Nanoparticles
T. Adschiri
Professor, WPI-Advanced Institute for Materials Research

1. Introduction
Nanoparticles of gold are known to mankind since Roman times. In naturenanomaterials exist ever since the earth came into existence. The term nanotechnology
was first used by the Japanese researcher Taniguchi in 1974 when he referred to theability to engineer materials at the nanometer scale [1]. The main idea behind the usageof this terminology was the miniaturization in the electronics industry.
Today this term nanotechnology is popularly used to define technology where
dimensions and tolerances are in the range 1 – 100 nm, larger than size of atom until
about wavelength of light. What is certainly new is the availability of an extraordinarily
wide range of nano-sized materials, many of which have unique properties and exciting
applications [2]. The nanomaterials are known for their unique mechanical, chemical,
physical, thermal, electrical, optical, electronic, magnetic and specific surface area
properties, which in turn define them as nanostructures, nanoelectronics, nanophotonics,
nanobiotechnology, nanoanalytics, etc. During 1980s, the concept of size quantization
was formulated for semiconductors and accordingly nanoparticles possess unique
optical and electronic properties not observed for corresponding bulk samples [3,4].
In the last few years, a trend has been set in the processing of a new class ofnanomaterials including coordination polymers, in which isolated metal ions or clusters
are linked into arrays by organic ligands, and extended inorganic hybrids, such as
hybrid metal oxides in which there is M-O-M connectivity in 1-, 2-, or 3-dimensions.
Such hybrid frameworks represent an enormous class of new materials that can harness
the advantages and versatility of both organics and inorganics with a scope that is vastly
greater than the combined fields of coordination chemistry and organometallics. These
new class of organic-inorganic hybrid materials have a tremendous application potential
as sensors, biological tags, catalysts, bioelectronics, solar energy conversion, mechanics,
membranes, protective coatings, transparent pigments, electro-magnets, cosmetics, etc[5,6]. The concept of “hybrid inorganic-organic” materials exploded only very recently
with the birth of soft inorganic chemical routes, where mild synthetic conditions allow
access to chemically designed hybrid inorganic-organic materials [7,8]. The small sizeand high surface to volume ratio of the individual nanoparticles imparts distinct size
tunable physical and electronic properties that have prompted some to refer to them as“artificial atoms”. As the number of nanoparticle systems under strict synthetic control

73

has expanded, the parallel to the development of a “new periodic table” is also underconsideration [9].
A highly controlled self-assembly of these hybrid nanoparticles when dispersed inorganic solvents into two-dimensional and/ or three-dimensional ordered structures orsuper-lattice structures remains a relatively unexplored area. In recent years, there arelots of publications on such self-assembled nanoparticle structures in the literature. It is
to be noted that a major challenge in the nanomaterial fabrication whether organic, or
inorganic or composite nanoparticles, is the preparation of highly dispersible
unagglomerated nanoparticles with an accurate control over the size and shape, which
in turn is directly linked with the nanomaterial processing method. Owing to the higher
surface energy of the particles in nanoscale, there is a greater tendency for nanoparticles
agglomeration and aggregation. At the same time, it is difficult to break down theaggregation of nanoparticles into individual particles size. Therefore, a new strategy for
an effective solution to this problem has to be worked out. In this context, thehydrothermal technique can be very effective to combat these issues in nanomaterials
fabrication. On the whole, the hydrothermal technique is gaining popularity in recent
years for processing a wide range of materials in the polyscale i.e. from bulk tonanosize [10-12].
2. Supercritical Hydrothermal Technique
2.1 What is Supercritical Hydrothermal Technique?
The term hydrothermal can be defined as any homogeneous or heterogeneous
chemical reaction in the presence of a solvent (whether aqueous or non-aqueous) above
the room temperature and at pressure greater than 1 atm in a closed system [10]. There
are several other related terms commonly used in hydrothermal like solvothermal,
supercriticalhydrothermal,
glycothermal,
alcothermal,ammonothermal,
carbonothermal, lyothermal, and so on. These different terms are basically used
depending upon the type of solvents employed in the reactions. Each one of thesetechniques has some specific advantages and suitable for processing of a particular typeof materials. The conventional hydrothermal refers to the reactions in the presence ofan aqueous solvents, and solvothermal refers to the non-aqueous solvents. The
ammonothermal refers to the ammonium based solvents, which are probably the bestfor the processing of nitrides including GaN. Similarly, the supercritical hydrothermalrefers to the reactions near or above critical temperature.
The supercritical hydrothermal technique has a lot of other advantages as it accelerates
interactions between solid and fluid species, phase pure and homogeneous materials canbe achieved, reaction kinetics can be enhanced, the hydrothermal fluids offer higher
diffusivity, low viscosity, facilitate mass transport and higher dissolving power. Most

74

important is that the chemical environment can be suitably tailored. A great variety ofmaterials have been obtained using the supercritical hydrothermal method.
The basic principle used in the hydrothermal synthesis of nanoparticles is that thesolute raw material or the precursor material along with the appropriate solvent are
taken in an autoclave which is maintained at a high temperature either below or above
the critical temperature of the solvent over a period of time, which allows the solute todissolve and recrystallize to the desired product. The solvent becomes highly corrosive
under elevated temperature and pressure conditions and majority of the substances
show higher solubility under hydrothermal conditions.
A fluid is supercritical when its temperature and pressure are higher than their criticalpoint values (Tc, Pc), as shown in Fig.1. Most of the interesting applications ofsupercritical fluids occur at 1< T/Tc <1.1 and 1<P/Pc< 2 [13], since the properties
change greatly around the critical point (Figs.1 and 2). Under these conditions the fluid
exists as a single phase for light gas-water or organic molecules-water (Figs.3 and 4).
Further, supercritical hydrothermal is also known for making new materials under mild
conditions, since they increase the chemical reactions, improve the mass transfer, andgreatly assist in the stability of selected or desired products [14-16].

Figure 2. Dielectric constant ofwater.

Figure 1. Density-pressuretemperature curve for water.

75

Figure 3. Critical loci for light gas-water
systems.

Figure 4. Critical loci for water-organic
compounds systems.

2.2 Apparatus for nanoparitcle synthesis in supercritical fluid
There is a wide range of apparatus used in the supercritical hydrothermal research tosuit the specific conditions and the product. However, the most commonly usedapparatus are batch reactors and flow reactors.
The batch reactors are the cone-cold sealed type autoclaves usually made of hastalloy
or stainless steel (SS316) with an ease to handle because of simple reactor design. A
typical inner volume of these batch reactors is usually 5 mL. Sometimes the platinum
lining or platinum capsules are provided to these reactors to prevent the corrosion.
Depending upon the pressure and temperature of the reaction and density of water inthose conditions, a required amount of precursors are loaded into the reactor. These
reactors can be stirred or shaken during the experiments. A series of such batch reactors
can be mounted on a single frame and experiments can be run conveniently by varying
several experimental parameters.The
experimental duration is normallyvaried from 5 minutes to several hours.
Figure 5 shows the schematic diagram
and a typical batch reactor. The
product recovery process from thebatch reactors is very important while
dealing with nanoparticles fabrication.
Figure 6 shows the typicalexperimental set up used in the flow
type of hydrothermal reactor. An
Figure 5. Batch reactor.
aqueous metal salt solution is first76

prepared and fed into the apparatus in one stream. In another stream, distilled water ispressurized and then heated to a temperature above the desired reaction temperature.
The pressurized metal salt solution stream and the pure scH2O stream are then
combined at a mixing point, which leads to rapid heating and subsequent reactions in
the reactor. After the solution leaves the reactor, it is rapidly quenched. In-line filters
are used to remove larger particles. Pressure is controlled with a back-pressure
regulator. Fine particles are collected in the effluent. By this rapid heating method, theeffect of the heating period on the hydrothermal synthesis is eliminated; thus specificfeatures of supercritical hydrothermal synthesis can be elucidated. There are several
advantages in supercritical hydrothermal flow reactors, which provide nanoparticles
with desired shape, size and composition in a shortest possible residence time. Hence,
this technique has an edge over the conventional methods.

Figure 6. Schematic of a typical flow reactor.

3. Supercritical hydrothermal synthesis of hybrid organic-inorganic
nanoparticles
3.1 Supercritical hydrothermal synthesis of metal oxides
A wide range of metal oxide nanoparticles have been obtained under supercriticalhydrothermal conditions for applications not only in ceramics, coatings, catalysts,
sensors, semiconductors, magnetic data storage, solar energy devices, ferrofluids, butalso in medicalfield such as hyperthermia, bioimaging, cell labeling, special drugdelivery systems, and so on. However, their application potential is dictated by theirsurface nature, particle size, and also shape. Although the synthesis of metal oxides is77not new, their applications were limited. With the discovery of size quantization effectin these materials during 1980s, there is a seminal progress in the synthesis of these
metal oxides with desired properties for several new applications. Researchers like
Adschiri, Arai, Johnston, Lester and Poliakoff, etc. have contributed extensively on thesynthesis of metal oxides and proposed a systematic mechanism [15-17]. Metal oxides
as Al2O3, Ga2O3, In2O3, SiO2, GeO2, ZnO2, V2O5, TiO2, CeO2, ZrO2, CoO, α-Fe2O3, γFe2O3, NiO, Co3O4, Mn3O4, γ-MnO2, Cu2O, CoFe2O4, ZnFe2O4, ZnAl2O4, Fe2CoO4,
BaZrO3, BaTiO3, BaFe12O19, LiMn2O4, LiCoO2, La2O3, etc., have been prepared by theabove method. Usually the particles obtained in the subcritical water conditions arelarger than those in the scH2O, because, there is a particle growth with an increase in
the residence time, whereas under supercritical conditions such a phenomenon has notbeen observed. The hydrothermal reaction rate in scH2O is higher, and the solubility ofthe metal oxides is much lower than that in subcritical water. This leads to thegeneration of higher degree of supersaturation. The nucleation rate is expected by thefunction of degree of supersaturation and the surface energy according to the nucleation
theory. Thus, extremely high nucleation rate can be expected at supercritical conditions,which leads to the formation of nano-size particles. Figure 7 shows the mechanism forthe fine CeO2 particles formation in scH2O. More or less a complete list of thematerials obtained under supercritical hydrothermal conditions is available in the works
of Reverchon and Adami (2006) and Byrappa and Adschiri (2007) [11,18]. Basicallyhydrothermal synthesis method is available for the metal oxides by conventionalhydrothermal synthesis method. The point to be noted here is that under supercriticalhydrothermal conditions, nanometer size metal oxides could be synthesized andcrystallinity of the nanoparticles
would be much higher whencompared to the metal oxides
obtained under conventionalhydrothermal conditions, whereinbulk single crystals are formed.
This sometimes leads to thespecific characteristics of the
products. Phosphor nanoparticles
show high luminescence without
heat treatment which is usuallynecessary for the products
obtained by low-temperature wet Figure 7. Mechanism of CeO2 nanoparticles formation
under supercritical hydrothermal conditions.
method [19,20].

78

3.2 Supercritical hydrothermal synthesis of organic-inorganic hybrid nanoparticles
In order to resolve the problem of particle aggregation, to achieve the perfect control
over the size and morphology of the particles, and to obtain a desired surface property
to the nanoparticles, a new processing strategy has been proposed by Adschiri andgroup utilizing the supercritical hydrothermal technology [12,21-25]. Figure 8 shows aschematic representation of highly effective strategy for the synthesis of metal oxide
nanocrystals in the organic-ligand assisted supercritical hydrothermal technology [21].
The method yields perfect hybrid organicinorganic nanocrystals with very highdispersibility, and a precise control
over the size and shape of thenanoparticles, as shown in Figure
9. The organic components are
introduced into the system during
the hydrothermal synthesis and insitu surface modification is
Figure 8. The strategy for the synthesis of metal
obtained with a ultra-thin layer of oxide nanocrystals in the organic-ligand assistedorganics surrounding the inorganic supercritical hydrothermal technique [21].
unlike the case of silane couplingon the metal oxides. The organic ligands and supercritical water form a homogeneous
phase (Fig.4) and it is known that under these conditions water molecules themselves
work as acid or base catalyst for various organic reactions. Depending upon theapplications of nanoparticles, one can select suitable functional groups to introducehydrophobicity or hydrophilicity property to the surface of the modified nanoparticles.
Understanding on the mechanism of formation of organic-inorganic hybrid
nanoparticles is very important and it deals with the interaction of the organic ligand
molecules with the inorganic metaloxide surfaces. Adschiri and his group
have worked out in detail the theory
and mechanism of the hybrid organicinorganic nanoparticle formation under
supercritical hydrothermal conditions.
Organic
modification
In order to understand the mechanismof this hybrid nanoparticles formation,
it is necessary to investigate the charge
distribution on the surface of the metal Figure 9. Organic-inorganic hybrid nanocrystals
synthesized in supercritical water.
oxide particles, which in turn reveal
the chemical interaction between themodifier and the surface of the metal oxide nanoparticle. In aqueous systems,
metaloxide particles are hydrated and M-OH groups cover completely their surface and79the surface is neutral. The M-OH sites on the surface of particles can react with H+ or
OH- ions from dissolved acids or bases, and positive (M-OH2+) or negative (M-O-)
charges develop on the surface, and type of the reaction depends on pH of the solution.
In the absence of specific adsorption of ions, amphoteric metal oxides have acharacteristic pH, the pH of the point of zero charge (PZC), where the net surface
charge is zero, i.e. the positive and negative sites are in equal amount (isoelectric point,iep). At pH lower than iep, the pure metal oxide surface is positively charged, while it
has negative charge above it [26-28].
Normally the modifiers attach onto
the surface of the nanoparticles either
by physisorption or chemisorptions
through strong hydrogen bond. If weconsider R-COOH as modifier
reagents in a highly acidic pH of thereaction medium, the dissociation ofmodifier does not occur and the
conjugation is due to the stronghydrogenbonding
betweenhydroxylic groups on the surface of
nanoparticles and functional groups
of modifier [29]. If the pH of thereaction medium is in the range ofmodifier dissociation, another type ofinteraction between the modifier andthe metal oxide surfaces is expected[30]. Similar chemical bonding is
expected even for amines or alcoholor aldehyde as the organic ligands inthe system. The addition of surface
modifiers also helps to inhibit the
crystal growth that facilitates thesmaller particles size with a narrow
particle size distribution. Figure 10 Figure 10. TEM images of hybrid nanoparticles
shows nanoparticles of Fe2O3, Co3O4, synthesized under supercritical hydrothermal
conditions: a) Fe O (without modifier); b) Fe2O3
CeO2, and CoAl2O4 obtained under (with modifier);2 c)3 Co O (without modifier);
3 4supercritical hydrothermal conditions d) Co3O4 (with modifier); e) CeO2 (without
without and with organic modifiers. modifier); f) CeO2 (with modifier); g) TiO2
As is clearly seen from Figure 5, (without modifier); h) TiO2 (with modifier) (fromthose nanoparticles without modifier the works of Adschiri).
are aggregated and they do not80disperse in the aqueous solvents. Also the particle size is larger compared to themodified particles. When the pH of the reaction medium is highly acidic or highly
basic, very small particles along with the large particles are formed leading to a broader
size distribution. It seems that because of redissolving of nanoparticles at very high andlow pH, Ostwald repining occurs. Therefore, in surface modification, pH of themedium, isolectric point (iep) and another important parameter, viz. dissociation
constant (pKa) of the modifiers are very important. At pH below pKa, the modifier does
not dissociate. Moreover, below iep, the surface of metal oxide nanoparticles issurrounded by positive charges (major) and hydroxylic groups (minor). Under these
conditions there is no chemical reaction occurring between the modifier and the metaloxide nanoparticle surface, but it is only through a strong hydrogen bonding themodifier can attach to the nanoparticles surface. In contrary, at higher pH than pKa,
dissociation of modifier takes place and results in chemical reaction between
dissociated part of modifier andOH2+ from particles surface. Thus,
by dehydration reaction modifierattaches to the surface of theparticles.
The possible different
types of conjugation between thesurface modifier and the surface ofthe nanoparticles are schematically
represented in Figure 11.
Byconsidering the chemical reactions,mass balances, charge balance in theactual system, pH and the modifier
Figure 11. Schematic representation of thecan be fixed for most of the systems.
reaction mechanism of in-situ surface
From the literature data, the values
modification of metal oxide nanoparticles
of pKa for several surfactants arewith R-COOH as a modifier (from Adschiri’s
available.
work).
3.3 Study of the supercritical hydrothermal synthesis of organic-inorganic hybrid
nanoparticles with size and shape control
The experimental studies on the preparation of some selected organic-inorganic hybrid
nanoparticles under supercritical hydrothermal conditions are discussed here based on
the discussion in the previous section. Figure 12 shows the schematic diagram of the
shape control of ceria nanoparticles under supercritical hydrothermal conditions in thepresence of organic ligand molecules [21]. The ceria nanocrystals unmodified weretruncated octahedral, which corresponds to the results of the earlier workers [31].
However, when decanoic acid was introduced into the system under supercritical81

hydrothermal conditions, the organic ligand molecules become miscible with water,
they contribute to the change in morphology of ceria nanocrystals from truncatedoctahedral to cube, which is mainly because of the suppression of the crystal growth on
the (001) face. When decanoic acid (molar ratio to ceria precursor 6:1) was added to
the reaction system, the resulting nanocrystals were nanocubes with an average size of 6
nm. As the CeO2 (001) surface is less stable than the (111) surface, the organic ligand
molecules were likely to interact preferentially with the (001) surface thereby reducing
the crystal growth along the [001] direction. If the amount of decanoic acid was further
increased (molar ratio to ceria precursor, 24:1), the ceria nanocrystal size decreased toabout 5 nm, and the shape of the nanocrystals also changed drastically, because of thegrowth inhibition not only along the [001] direction, but also along the [111] direction.
(a)

(b)

(c)

Figure 12. The shape control of ceria nanoparticles: a) truncated octahedron in the casewhen no organic ligand molecules are used; b) at a low decanoic acid to ceria precursor
ratio, the preferential interaction of the ligand molecules with the ceria (001) planes slows
growth of (001) faces relative to (111) faces, which leads to the formation of nanocubes; c)
at a high deconoic acid to ceria precursor ratio, organic ligand molecules block growth on
both (001) and (111) faces, which leads to the formation of truncated octahedral and smaller
crystals.

3.4 Dispersibility of organic-inorganic hybrid nanoparticles
It is to be noted that the surface modified organic-inorganic hybrid nanoparticles
synthesized under supercritical hydrothermal conditions can be easily recovered by82extraction with organic solvent from the water suspension phase, and well dispersed inorganic solvents. Normally transparent solutions are obtained for the well crystallized
and very small hybrid nanoparticles when dispersed. Through the dynamic lightscattering (DLS) studies also, it can be confirmed that the particles are not aggregated,but suspended as individual nanoparticles. Figure 13 shows the perfect dispersion of
CeO2 nanoparticles in the organic solvents.
(c)

(a)

(b)

Figure 13. Perfect dispersion of CoAl ₂ O ₄ nanoparticles (b) in water (a) and CeO ₂
nanoparticles in the organic solvent (c). Tyndall effect was clearly observed (c).

4Recent topics
Finally, the recent topics regarding supercritical hydrothermal synthesis technique are
introduced briefly here. There are mainly three topics under extensive research in ourgroup now. These three topics are all based on the unique properties of organicinorganic hybrid nanoparticles synthesized in supercritical fluid as mentioned in theprevious sections(Fig.14).

Figure 14. Evolution of organic-inorganic hybrid nanoparticles: Self-assembly of organic
modified nanoparticles, hybrid polymer molecules, and bio-imaging probes.

834.2 Self-assembly of organic-inorganic hybrid nanoparticles
Self-assembly is a generic term used to describe a process leading to the orderedarrangement of molecules and small components such as small particles like
nanoparticles occurring spontaneously under the influence of certain forces such as
chemical reactions, capillary forces and electrostatic attraction, etc. Self-assembly andmore generally self-organization of particles in a solvent is considered to be a powerfulprocess for building patterns up to nanoscopic level through multiple interactions
among the components of the system under consideration. Ordered assemblies ofnanometer size particles represent an interesting class of nanomaterials that provide
exceptional potentials for a wide variety of applications. These structures would be
useful for various applications like displays, sensors, data storage, photonic band gap
materials, etc owing to their exceptional physical, chemical and electronic properties[32-35]. Common approaches to noncovalent assembly strategies employ van der
Waals/ packing interactions, hydrogen bonding, ion pairing, and host-guest inclusion
chemistry [36-39]. These self-assembly methods provide direct access to extended
structures from appropriately designed nanoparticle building blocks. Although theassembly of nanoparticles from solution into close-packed monlayers and super-lattice
structures on solid surfaces has met with a fair degree of success [40-42], and incontrary, the controlled assembly of nanoparticles in the organic solvent has not been
understood precisely. In order to meet the major challenge in nanotechnology inrealizing many of the desired technological goals, the self-assembly provides a possible
convenient route, but controlling size, size distribution, shape, and surface chemistriesof the nanohybrid particles is critical in achieving desired structures. Initial syntheses
have yielded nearly spherical shapes due to the thermodynamic driving force ofminimizing surface area, and self-assembly has been limited to the close-packing of
spheres [43,44]. The several reviews are published on this aspect [45,46]. However, it
is to be noted that the self-assembly of hybrid organic-inorganic nanoparticles
synthesized through supercritical hydrothermal routes are seldom found in the literature.
4.3 Super hybrid nanoparticles with Polymers
After successful production of surface modified nanopartilces, we have been trying to
manufacture polymer-surface modified nanoparticle hybrid materials. In principle,
inorganic material and organic compounds have tradeoff functions e.g. hard and soft,
electro conductivity and insulation and highly thermal conductivity and adiathermic andso on, so that inorganic and polymer hybrid blends must show these tradeoff functions
at the same time. According to the background, we’re in charge with the New Energy
and Industrial Technology Development Organization (NEDO) granted program:
Development of Super-Hybrid materials. Among the series of high performance84

functional hybrid materials the target materials are focused on high refractive index
materials and high thermal conductive materials in the project. For high refractive index
materials, the single nano-sized high refractive index fillers have to be dispersed thepolymer matrix without aggregation at high volume concentration, furthermore thematerial should keep the plasticity for further fabrications and of course thetransparency against to visible light has to be achieved. For high thermal conductivity
materials, the linkage between the inorganic fillers and total design of the hybridmaterials are important. These tradeoff functions have to be accomplished for the new
hybrid materials.
4.4 Bioimaging and Super drug delivery using water soluble nanoparticles synthesized
in supercritical fluid
Recently, the cancer diagnosis and treatment using nanoparticles is extensively
investigated. To image the tissues, comparably heavy metals are generally used such as
Gd for Magnetic Resonance Imaging. These heavy metal ions are toxic and such kindof nanoparticles should be stable in the body. We take particular note of chemical
stability of metal oxide nanoparticles synthesized in supercritical fluid. Modification of
the surface of nanoparticles is also important to fit those particles to the living body aswell as suppression of agglomeration of the particles. We can use the same techniqueas synthesis of organic-inorganic hybrid nanoparticles as mentioned above. Only
difference is that nanoparticles should be dispersed not in organic solvent but in water.
We are now trying synthesis nanoparticles soluble to water now. Agglomeration freenanoparticles without surfactant that may lead to biological toxin are strongly needed torealize bioimaging with high accuracy and safety.
5

Summary
Supercritical hydrothermal synthesis of advanced nanomaterials like organic-inorganic
hybrid nanoparticles has been reviewed in detail starting from the basic principles to thespecific features of the methodology. The supercritical fluids are very active in suchextreme PT conditions and are highly suitable to synthesize even complex structures,
because of the drastic change in the fluid properties like density and dielectric constant,which in turn lower the solubility of the materials. Although supercritical hydrothermal
technique gives highly crystalline nanoparticles with homogeneous composition, still
there is a problem of larger size, coagulation and poor dispersibility of nanoparticles inaqueous solutions. Hence, there is a trend to use organic ligands, capping agents,
surfactants, etc., which generate a new class of nanomaterials, viz. organic-inorganic
hybrid nanomaterials. This strategy is based on the miscibility of the organic ligand
molecules with supercritical water due to the lower dielectric constant of the water; andthe nanocrystal shape control by selective reaction of organic ligand molecules to thespecific inorganic crystal surface. A great variety of organic ligand molecules including

85

DNA, proteins, peptides, amino acids, decanoic acid, oleic acid, etc. have been used forthis purpose to obtain high quality organic-inorganic nanoparticles, which can be usedas sensors, phosphors, data storage, photonic band gap, displays, biomedical, etc.
These hybrid nanoparticles can be obtained with such a precise size and shape control.
They show excellent dispersibility in the organic solvents and also self-assemble toform super-lattice structures. By choosing different types of modifiers with varying
carbon chain length, the super-lattice of the self-assembled nanoparticles can bemonitored precisely. Hence the supercritical hydrothermal synthesis method holds a
strategy for the future advanced nanomaterials processing.
6

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87

WPI-AIMR Newly
Appointed Research Staff

Curriculum Vitae

Dmitri V. LOUZGUINE
Professor
E-mail: dml@imr.tohoku.ac.jp
ACADEMIC:
1984-1991 Undergraduate Student, Moscow State Institute of Steel and Alloys,
Moscow, Russia
1995-1998 Dr. Eng. Course, Tohoku University, Japan
ACADEMIC DEGREE: Doctor of Engineering, 1998, Tohoku University, Japan
PROFESSIONAL EXPERIENCE:
1991-1994
Researcher, Moscow State Institute of Steel and Alloys, Moscow, Russia
1998-2005
Research Associate, Institute for Materials Research, Tohoku University, Japan
2005-2007
Associate Professor, Institute for Materials Research, Tohoku University, Japan
2007-present
Professor, WPI Advanced Institute for Materials Research, Tohoku University, JapanSCIENTIFIC PUBLICATIONS:✦ 162 research and review papers in world-leading peer-reviewed Journals (about 90% of which are ISI
indexed) including Acta Materialia (4 papers), Applied Physics Letters (12), Materials Science andEngineering (8), Journal of Materials Research (6), Philosophical Magazine (3) and many others.
✦ 5 chapters in books.
✦ 10 Invited Talks at International Conferences.
RECOGNITION:✦Monbusho scholarship awarded to complete Dr. Eng. Course, Japan (1994)✦ Young participating scientist award at 9th International Symposium on Metastable, Mechanically
Alloyed and Nanocrystalline Materials (ISMANAM 2002) Sept. 8-12, Seoul (2002)✦MRS 2007 Fall Meeting Best Poster Award: T. Wada, D. V. Louzgine-Luzgin and A. Inoue MRS 2007
fall meeting, Boston, USA

CURRENT RESEARCH:
Investigation of thermal stability, structure, formation mechanisms, phase transformations, deformation
behaviour, mechanical and physical properties of bulk metallic glasses, metallic glasses, nanostructured
crystalline/quasicrystalline materials, composite materials having a mixed structure containing
nanoparticles embedded in the glassy matrix and high-strength crystalline alloys. I have a long-term
experience in various types of structural analysis techniques. In particular, Transmission Electron
Microscopy (TEM) of nanostructured and glassy materials including nanobeam diffraction and highresolution TEM imaging. Extraction of radial distribution functions from Synchrotron-radiation XRD data.
I also apply computer-simulation to materials science (phase transformations, crystallography).

91

Curriculum Vitae

Kazuto AKAGIAssociate Professor
E-mail: akagi@wpi-aimr.tohoku.ac.jp
URL: http://mtweb.wpi-aimr.tohoku.ac.jp/

ACADEMIC:
1994 B.S. in Physics, The University of Tokyo, Japan
1996 B.S. in Physics, The University of Tokyo, Japan
1999 Dr. in Physics, The University of Tokyo, Japan
PROFESSIONAL EXPERIENCE:
1999
JSPS Fellow (PD), Institute for Solis State Physics, The University of Tokyo, Japan
1999-2002
Research Associate, Institute for Solis State Physics, The University of Tokyo, Japan
2002-2008
Research Associate, Department of Physics, Graduate School of Science, The Universityof Tokyo2008-present
Associate Professor, WPI Advance Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Investigation of chemical reaction process at various surfaces and solid/liquid interfaces based on firstprinciples molecular dynamics calculation. Development of computational simulation method for scanningprobe microscopy.

Taro HITOSUGIAssociate Professor
E-mail: hitosugi@wpi-aimr.tohoku.ac.jp
URL: http://www.wpi-aimr.tohoku.ac.jp/jp/hashizume_lab/Welcome/Welcome.html

ACADEMIC:
1994 B.S. in Engineering, The University of Tokyo, Japan
1996 M.S. in Engineering, The University of Tokyo, Japan
1999 Dr. Eng., The University of Tokyo, Japan
PROFESSIONAL EXPERIENCE:
1999-2003
Researcher, Sony Corporation, Japan
2003-2007
Assistant Professor, Department of Chemistry, The University of Tokyo, Japan
2003-present
Researcher, Kanagawa Academy of Science and Technology (KAST), Japan
2007-present Associate Professor, Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦Solid State Chemistry, Solid State Physics, Surface Science✦Studies on inorganic/organic thin films and nano-scale oxide materials.

92Curriculum Vitae

Ken NAKAJIMA
Associate Professor
E-mail: knakaji@wpi-aimr.tohoku.ac.jp

ACADEMIC:
1992 B.E. in Applied Physics, The University of Tokyo, Japan
1994 M.E. in Applied Physics, The University of Tokyo, Japan
1997 Dr. Eng. in Applied Physics, The University of Tokyo, Japan
PROFESSIONAL EXPERIENCE:
1997-1999
Special Postdoctoral Researcher, Frontier Research System, RIKEN, Japan
1999-2003
Frontier Researcher, Frontier Research System, RIKEN, Japan
2003-2008
Assistant Professor, Tokyo Institute of Technology, Japan
2008-present Associate Professor, Tohoku University
CURRENT RESEARCH:
Single molecular detection by scanning probe microscopy, polymer physics, nanorheology andnanotribology of polymeric surfaces and single polymer chains, basic studies on rubbery elasticity

Koji S. NAKAYAMA
Associate Professor
E-mail: kojisn@imr.tohoku.ac.jp
ACADEMIC:
1990 B.S. in Applied Physics, Tokai University, Japan
1992 M.S. in Engineering, Yokohama National University, Japan
1995 Dr. Eng. in Engineering, Yokohama National University, Japan
PROFESSIONAL EXPERIENCE:
1995-1996
Research Scientist, Department of Engineering, Yokohama National University, Japan
1996-1999
Postdoctoral fellow, Department of Chemical Engineering and Materials Science,
University of Minnesota, USA1999
Postdoctoral fellow, Department of Chemistry, The University of Tokyo, Japan
1999-2001
Lecturer, Institute for Materials Research, Tohoku University
2001-2005
Visiting Research Assistant Professor, Department of Materials Science andEngineering, University of Illinois at Urbana-Champaign, USA
2005-2008
Associate Professor, Institute for Materials Research, Tohoku University
2008-present Associate Professor, WPI-Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦Growth and characterization of nanowires of metallic glassy alloys✦Mapping of the electronic density of states using scanning tunneling spectroscopy

93

Curriculum Vitae

Peter SUSHKO
Associate Professor
E-mail: p.sushko@wpi-aimr.tohoku.ac.jp
ACADEMIC:
1994 B.S. in Physics, St. Petersburg State University, Russia
1996 M.S. in Quantum Theory of the Solid State, St.Petersburg State University, Russia
2000 Dr. Physics, The Royal Institution of Great Britain and University College
London, UK
PROFESSIONAL EXPERIENCE:
2000
Visiting Researcher, Environmental Molecular Sciences Laboratory (EMSL), PacificNorthwest National Laboratory (PNNL), Richland WA, USA
2000-2001
Research Assistant, Department of Physics & Astronomy, UCL, UK
2001-2004
Research Fellow, Department of Physics & Astronomy, UCL, UK
2005-2007
Senior Research Fellow, Department of Physics & Astronomy, UCL, UK
2007-2008
Senior Research Fellow, London Centre for Nanotechnology, UCL, UK
2008-present
Associate Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦ Theoretical/computational modelling of defect processes in the bulk and at surfaces of ionic materials.
✦ Photo-induced excited states, charge trapping, and mechanisms of defect formation in oxide
nanostructures.
✦Photo-chemistry of oxide surfaces.
✦Mechanisms of photo-induced desorption.
✦Modelling of defects and mechanisms of defect processes in high-K materials and at their interfaces withSi.
✦Electronic properties of confined semiconductors and confined electron gas.
✦Novel computational techniques.

Akira TAKEUCHI
Associate Professor
E-mail: takeuchi@imr.tohoku.ac.jp
URL: http://www.inoue.imr.tohoku.ac.jp

ACADEMIC:
1988 B.S. in Metallurgy, Nagoya Institute of Technology, Japan
1990 M.S. in Materials Science and Engineering, Nagoya Institute of Technology, Japan
1993 Dr. in Materials Science and Engineering, Nagoya Institute of Technology, Japan
PROFESSIONAL EXPERIENCE:
1993-2003
Research Associate, Institute for Materials Research, Tohoku University
2003-2008
Associate Professor, Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Materials Science, Non-Equilibrium Materials, Computer Science, Metallic Glasses, Glass Transition,
Thermodynamics

94

Curriculum Vitae

Takayuki MAKINO
Lecturer
E-mail: tmakino@imr.tohoku.ac.jp

ACADEMIC:
1993 B.S. in Engineering Science, Kyoto University, Japan
1995 M.S. in Human and Environmental Studies, Kyoto University, Japan
1998 Dr. in Human and Environmental Studies, Kyoto University, Japan
PROFESSIONAL EXPERIENCE:
1998-2001
Special Postdoctoral Researcher, The Institute of Physical and Chemical Research(RIKEN), Japan
2001
Frontier Researcher, The Institute of Physical and Chemical Research (RIKEN), Japan
2001-2002
Foreign Postdoctoral Researcher at the CNRS, Laboratory of Physical Spectrometry,
University of Grenoble I, France
2002-2003
Frontier Researcher, The Institute of Physical and Chemical Research (RIKEN), Japan
2003-2005
Researcher, The Institute of Physical and Chemical Research (RIKEN), Japan
2005-2007
Research Associate, Graduate School of Material Science, University of Hyogo, Japan
2008-present Lecturer, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
The study of solid state photo-physics for optoelectronic applications based on oxide materials

Susumu TSUKIMOTO
Lecturer
E-mail: tsukimoto@wpi-aimr.tohoku.ac.jp
URL: http://www.wpi-aimr.tohoku.ac.jp/en/index.html
ACADEMIC:
1995 B.S. in Materials Engineering, Nagoya University, Japan
1997 M.S. in Quantum Engineering, Nagoya University, Japan
2000 Dr. Eng. in Quantum Engineering, Nagoya University, Japan
PROFESSIONAL EXPERIENCE:
2000
Postdoctoral Fellow, Venture Business Laboratory, Nagoya University, Japan
2000-2002
Postdoctoral Fellow, Max-Planck-Institute for Metals Research, Germany
2002-2007
Research Associate, Department of Materials Science and Engineering, Kyoto University
2007-2008
Assistant Professor, Department of Materials Science and Engineering, Kyoto University
2008-present Lecturer, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦ Cu-alloy thin films (interconnects) with self-formed barrier layers for LSI devices.
✦ Low resistance electrodes for wide-gap compound semiconductors.
✦Functional ceramics and metals controlled the interface (and defect) structures.

95Curriculum Vitae

Kotone AKIYAMA
Assistant Professor
E-mail: akiyama@mems.mech.tohoku.ac.jp
URL: http://www.mems.mech.tohoku.ac.jp/

ACADEMIC:
1996 B.S. in Physics, Tohoku University
1998 M.S. in Physics, Tohoku University
2006 Ph.D. in Physics, Tohoku University
PROFESSIONAL EXPERIENCE:
2004-2006
2006-2007
2007-2008
2008-present

Technical staff, Institute for Solid State Physics, The University of Tokyo, Japan
COE Post Doc., Institute for Materials Research, Tohoku University
Assistant Professor, Institute for Materials Research, Tohoku University
Assistant Professor, WPI Advanced Institute for Materials, Tohoku University

CURRENT RESEARCH:
Scanning probe microscopy aiming for data storage/Conductance measurement of nano-materials based onhigh-resolution AFM lithography

Abdullah AL-MAHBOOBAssistant Professor
E-mail: almahb-0@imr.tohoku.ac.jp
ACADEMIC:
1993 B.S. in Physics, Jahangirnagar University, Bangladesh
1995 M.S. in Physics, Jahangirnagar University, Bangladesh
2002 M.Phil. in Physics, Jahangirnagar University, Bangladesh
2007 Ph.D. (Science) in Physics, Tohoku University
PROFESSIONAL EXPERIENCE:
1995-2001
Lecturer, Department of Physics, Chittagong University of Engineering and Technology(Former BIT, Chittagong), Bangladesh
2001-2007
Assistant Professor, Department of Physics, Chittagong University of Engineering andTechnology, Bangladesh
2007-2008
Assistant Professor, Institute for Materials Research, Tohoku University
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦LEEM/PEEM and SPM study of growth and organization of nano-structured device materials, dynamical
phenomena on surfaces and growth of thin films✦Organic devices

96Curriculum Vitae

Takeshi FUJITA
Assistant Professor
E-mail: tfujita@imr.tohoku.ac.jp

ACADEMIC:
1998 B.S. in Material Science and Engineering, Kyushu University, Japan
2000 M.S. in Material Science and Engineering, Kyushu University, Japan
2003 Dr. in Material Science and Engineering, Kyushu University, Japan
PROFESSIONAL EXPERIENCE:
2003-2003
Assistant Professor, Department of Engineering, Kyushu University, Japan
2003-2005
Visiting scientist (JSPS fellow), Center for Solid State Science, Arizona State University,USA
2005-present Assistant Professor, Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Transmission electron microscopy such as energy-dispersive X-ray spectrometer (EDS), electron energyloss spectroscopy (EELS), high resolution electron microscopy (HVEM), electron holography, and electron
tomography for advanced materials.

Daisuke HOJO
Assistant Professor
E-mail: dhojo@tagen.tohoku.ac.jp
ACADEMIC:
1996 B.S. in Natural Sciences, University of Tsukuba, Japan
1998 M.S. in Science and Engineering, University of Tsukuba, Japan
2003 Dr. Eng. in Engineering, University of Tsukuba, Japan
PROFESSIONAL EXPERIENCE:
1999-2000
Part time Research assistant, Texas Instruments Japan, Japan
2000-2003
Doctoral Research, Department of applied physics, University of Tsukuba, Japan
2003-2005
AIST Research Fellow, Advanced Semiconductor Research Center, National Institute ofAdvanced Industrial Science and Technology (AIST), Japan
2005-2007
Post-doc., Institute of Multidisciplinary Research for Advanced Materials, Tohoku
University
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:✦Thin film deposition with exotic methods as supercritical field✦Constructing novel nano-structure by impregnating functionalized nanoparticles into porous materials✦Replicating template structure for optical and catalytic application✦Nanotechnology-based device development

97

Curriculum Vitae

Susumu IKEDA
Assistant Professor
E-mail: ikeda@atom.che.tohoku.ac.jp
URL: http://www.che.tohoku.ac.jp/~atom/

ACADEMIC:
1990 B.S. in Earth and Planetary Materials Science, Tohoku University
1997 M.S. in Geology (Earth and Planetary Materials Science), The University of Tokyo, Japan
2000 Dr. Sci. in Geology (Earth and Planetary Materials Science), The University of Tokyo, Japan
PROFESSIONAL EXPERIENCE:
2000-2002
JSPS Postdoctoral Fellow, Department of Complexity Science and Engineering,
The University of Tokyo, Japan
2003
21st COE Program Postdoctoral Researcher, Department of Chemistry, The University ofTokyo, Japan
2004
Postdoctoral Researcher, Department of Complexity Science and Engineering,
The University of Tokyo, Japan
2005-2006
Research Associate, Department of Complexity Science and Engineering, The Universityof Tokyo, Japan
2007
Assistant Professor, Department of Complexity Science and Engineering, The Universityof Tokyo, Japan
2008-present Assistant Professor, WPI Advanced Institute foe Materials Research, Tohoku University
CURRENT RESEARCH:✦Growth of high quality single crystals of organic semiconductor from solution✦ Electronic devices using single crystals of organic semiconductor✦ Oriented film growth of organic materials by graphoepitaxy

Daisuke ISHII
Assistant Professor
E-mail: dishii@tagen.tohoku.ac.jp
URL: http://poly.tagen.tohoku.ac.jp/Site/Top.html

ACADEMIC:
2001 B.A. in Engineering, Tokyo Institute of Technology, Japan
2003 M.S. in Engineering, Tokyo Institute of Technology, Japan
2006 Dr. Eng. in Engineering, Tokyo Institute of Technology, Japan
PROFESSIONAL EXPERIENCE:
2006-2007
Special Postdoctoral Researcher, Frontier Research System, RIKEN, Japan
2007-2008
Special Postdoctoral Researcher, Center for Intellectual Property Strategies, RIKEN
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦Dissimilar interface and functional surface.
✦Self-assembly and self-organization.
✦Organic-inorganic composite material.
✦Responsible material. (photo chemical, electro chemical, etc）

98

Curriculum Vitae

Jing JU
Assitant Professor
Phone: +81-22-795-6468 (Lab)
Email: jujing@sspns.phys.tohoku.ac.jp
ACADEMIC:
1996 B.S. in Chemistry, Jilin University, P.R.China
1999 M.S. in Chemistry, Jilin University, P.R.China
2006 Ph.D. in Chemistry, Peking University, P.R.China
PROFESSIONAL EXPERIENCE:
2003-2007
COE Fellow, Low Dimension, P.R.China
2007-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦The study of advanced space-charge transport materials based on transition metal borates.

Akiyoshi KUZUMEAssistant Professor
E-mail: kuzume@atom.che.tohoku.ac.jp
URL: http://www.che.tohoku.ac.jp/~atom/

ACADEMIC:
1999 B.S. in Chemistry, The University of Tokyo, Japan
2001 M.S. in Chemistry, The University of Tokyo, Japan
2004 Ph.D. in Chemistry, University of Liverpool, UK
PROFESSIONAL EXPERIENCE:
2004
Post-doctoral research fellow, University of Liverpool, UK
2004-2006
Post-doctoral research fellow, Institute of Electrochemistry, Alicante University, Spain
2006-2008
Research Associate, Keio University, Japan
2008-present Assistant Professor, WPI Advanced Institute for Materials research, Tohoku University
CURRENT RESEARCH:✦Electrochemical studies (atomic-scale etching processes) on solid/liquid interfaces using single
crystal metal and semiconductor surfaces.

99Curriculum Vitae

Hongwen LIU
Assistant Professor
E-mail: liu@wpi-aimr.tohoku.ac.jp

ACADEMIC:
1993 B.S. in Applied Physics, Dalian University of Technology, P.R.China
2001 Ph.D. in Electronic Physics, Peking University, P.R.China

PROFESSIONAL EXPERIENCE:
1993-1996
2001-2003
2003-2005
2005-2008
2008-present

Assistant Engineer, Shanghai Automation Instrumentation Co., Ltd., P.R.China
Assistant Professor, Institute of Physics, Chinese Academy of Sciences, P.R.China
Postdoctoral Fellowship, The Institute of Scientific and Industrial Research, Osaka
University, Japan
Specially Appointed Assistant Professor, The Institute of Scientific and Industrial
Research, Osaka University, Japan
Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:✦Scanning probe microscopy (SPM)-related surface science✦STM-induced molecular fluorescence✦Plasmonic photonics

Kimitaka MINAMI
Assistant Professor
E-mail: nankim@tagen.tohoku.ac.jp
URL: http://www.tagen.tohoku.ac.jp/labo/ajiri/

ACADEMIC:
2000 B.S. in Biochemical Engineering, Tohoku University
2002 M.S. in Chemical Engineering, Tohoku University
2005 Dr. in Chemical Engineering, Tohoku University

PROFESSIONAL EXPERIENCE:
2005-2006
2006-2007
2007-present

Research Fellow, Research Center for Compact Chemical Process,National Institute of Advanced Industrial Science and Technology, Japan
Post-doc., Institute of Multidisciplinary Research for Advanced Materials,
Tohoku University
Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:
The studies about the synthesis of organic surface-modified inorganic nanoparticles, and thedecomposition and solubilization of biomass, by using solvent effects of supercritical water andorganic solvents mixtures

100Curriculum Vitae

Sigemi MIZUKAMI
Assistant Professor
E-mail: mizukami@wpi-aimr.tohoku.ac.jp

ACADEMIC:
1996 B.S. in Applied Physics, Tohoku University
1998 M.S. in Applied Physics, Tohoku University
2001 Dr. Eng. in Applied Physics, Tohoku University

PROFESSIONAL EXPERIENCE:
2001-2005
Research Associate, College of Engineering, Nihon University, Japan
2005-2008
Lecturer, College of Engineering, Nihon University, Japan
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:✦The search for new and highly functionalized magnetic materials✦Spin dynamics for magnetic multilayer and novel magnetic materials✦Basic research of RF spintronics devices using spin momentum transfer

Masanori MUROYAMA
Assistant Professor
E-mail: muroyama@mems.mech.tohoku.ac.jp
URL: http://www.mems.mech.tohoku.ac.jp/

ACADEMIC:
2000 B.E. in Electrical Engineering and Computer Science, Kyushu University, Japan
2002 M.E. in Computer Science and Communication Engineering, Kyushu University, Japan
2008 Ph.D. in Computer Science and Communication Engineering, Kyushu University, Japan

PROFESSIONAL EXPERIENCE:
2005-2008
Assistant Professor, System LSI Research Center, Kyushu University, Japan
2008-present Assistant Professor, Tohoku University

CURRENT RESEARCH:✦The study of integration of LSI and MEMS using low-power and high-reliability design techniques forinnovative applications

101

Curriculum Vitae

Ryo NOUCHI
Assistant Professor
E-mail: nouchi@sspns.phys.tohoku.ac.jp
ACADEMIC:
2000 B.S. in Electronics, Doshisha University, Japan
2002 M.S. in Nuclear Engineering, Kyoto University, Japan
2005 Ph.D. in Nuclear Engineering, Kyoto University, Japan
PROFESSIONAL EXPERIENCE:
2005-2007
Research Fellow, Core Research for Evolutional Science and Technology, Japan Scienceand Technology Agency (c/o Department of Chemistry, Okayama University), Japan
2007-2008
Specially-Appointed Assistant Professor, Graduate School of Engineering Science, Osaka
University, Japan
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Molecular electronics using charge transport measurements by means of field-effect transistors and/or
adsorbate-solid interactions

Chunling QIN
Assistant Professor
E-mail: clqin@imr.tohoku.ac.jp

ACADEMIC:
1985 B.S. in Chemistry, Zhengzhou University, Zhengzhou, P.R.China
1988 M.S in Chemistry, Zhengzhou University, Zhengzhou, P.R.China
2003 Dr. Eng. in Materials Science and Engineering, Tohoku University
PROFESSIONAL EXPERIENCE:
1988-1991
Research Associate, Department of Chemistry, Huanghe University, P.R.China
1991-1996
Lecturer, Department of Chemistry, Zhengzhou University, P.R.China
1996-2000
Lecturer, Department of Chemistry, Hebei Normal University, P.R.China
2003-2004
Postdoctoral fellow, Institute for Materials Research, Tohoku University
2004-2007
Researcher, Japan Science and Technology Agency (JST), Japan
2007-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦ The study of advanced nonequilibrium metallic materials with amorphous/glassy or glassy composites etc.
exhibiting useful physical and chemical properties

102

Curriculum Vitae

Pierre RICHARD
Assistant Professor
E-mail: p.richard@arpes.phys.tohoku.ac.jp
URL: http://arpes.phys.tohoku.ac.jp/index-e.html
ACADEMIC:
1998 B.S. in Physics, Université de Sherbrooke, Canada
2000 M.S. in Physics, Université de Sherbrooke, Canada
2004 Ph.D. in Physics, Université de Sherbrooke, Canada
PROFESSIONAL EXPERIENCE:
2005-2008
Postdoctoral Fellow, Department of Physics, Boston College, USA
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦Photoemission study of the electronic band structure of transition metal oxides and other complex
materials (cuprates, cobaltates, ruthenates etc …)

Mitsuhiro SAITOAssistant Professor
E-mail: saito@wpi-aimr.tohoku.ac.jp
URL: http://www.wpi-aimr.tohoku.ac.jp/en/index.html
ACADEMIC:
1999 B.S. in Physics, Gakushuin University, Japan
2001 M.S. in Materials Science, The University of Tokyo, Japan
2004 Ph.D. in Materials Science, Universität Stuttgart, Germany
PROFESSIONAL EXPERIENCE:
2001-2005
Ph.D./Scientific Co-worker, Max-Planck-Institute for Metals Research, Germany
2005-2006
Postdoctoral Fellow, Max-Planck-Institute for Metals Research, Germany
2006-2008
Postdoctoral Fellow, Advanced Electron Microscopy Group, National Institute forMaterials Science, Japan
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Quantitative analysis of a local atomic structure of a crystal interface, a grain boundary, and a strongly
correlated electron material by an annular dark field (ADF) image in a scanning transmission electron
microscopy (STEM) and by a high resolution transmission electron microscopic (HRTEM) image.

103

Curriculum Vitae

Seigo SOUMA
Assistant Professor
E-mail: s.souma@arpes.phys.tohoku.ac.jp
URL: http://www.arpes.phys.tohoku.ac.jp

ACADEMIC:
1999 B.S. in Physics, Tohoku University
2002 M.S. in Physics, Tohoku University
2005 Dr. Sci., in Solid-State Physics, Tohoku University
PROFESSIONAL EXPERIENCE:
2005-2006
Postdoctoral Fellowship for Research Abroad, JSPS, Japan
2006-2007
Assistant Professor, Department of Physics, Tohoku University
2007-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦Development of spin-resolved ultrahigh-resolution angle-resolved photoemission spectrometer✦Development of high-brilliance plasma discharge lamp for ultra-high resolution photoemission s
pectroscopy✦Electronic structure of ordinal or newly discovered exotic superconductors✦Electronic structure of heavy Fermion rare-earth compounds

Kazunori UENO
Assistant Professor
E-mail: uenok@imr.tohoku.ac.jp

ACADEMIC:
1999 B.S. in Engineering, The University of Tokyo, Japan
2001 M.S. in Science, The University of Tokyo, Japan
2004 Ph.D. in Advanced Materials Science, The University of Tokyo, Japan
PROFESSIONAL EXPERIENCE:
2001-2004
Visiting Scientist, National Institute for Advanced Industrial Science and Technology(AIST), Correlated Electron Research Center (CERC), Japan
2002-2003
Graduate student researcher, New Energy and Industrial Technology Development
Organization (NEDO), Japan
2004-2008
Researcher, Institute for Materials Research, Tohoku University
2008-present Assistant Professor, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Thin film fabrications and device applications of oxide materials for utilizing their various physicalproperties.

104

Curriculum Vitae

Luyang CHEN
Research Associate
E-mail: chenly@imr.tohoku.ac.jp

ACADEMIC:
2001 B.S. in Material Chemistry, Nanjing University of Science and Technology,
P.R.China
2006 Dr. Sci. in Inorganic Chemistry, University of Science and Technology of China,
P.R.China
PROFESSIONAL EXPERIENCE:
2006-2007
BK21 Postdoctoral Fellow, Korea University, Korea
2007-present
Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Nanoporous metals materials fabrication, surface enhanced Raman scattering (SERS) properties, and theirapplications in electrocatalysis.

So FUJINAMI
Research Associate
E-mail: fujinami@wpi-aimr.tohoku.ac.jp

ACADEMIC:
2002 B.S. in Applied Physics, The University of Tokyo, Japan
2004 M.S. in Applied Physics, The University of Tokyo, Japan
2007 Ph.D. in Organic and Polymeric Materials, Tokyo Institute of Technology, Japan
PROFESSIONAL EXPERIENCE:
2007-2008
Postdoctoral Fellow, Institute of Materials Structure Science, High Energy Accelerator
Research Organization, Japan
2008-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Measurement and analyses of nanomechanical properties of polymeric and organic materials, especiallyusing atomic force microscopy.

105Curriculum Vitae

Nobuyuki FUKUI
Research Associate
E-mail: n-fukui@wpi-aimr.tohoku.ac.jp

ACADEMIC:
2003 B.S. in Chemistry, Nagoya University, Japan
2005 M.S. in Chemistry, Nagoya University, Japan
2008 Ph.D. in Chemistry, Nagoya University, Japan
PROFESSIONAL EXPERIENCE:
2005 - 2007
Research Assistance (COE), Nagoya University, Japan
2006 - 2007
Grant for young Scientist in COE, Nagoya University, Japan
2007 - 2008
Research Assistance (G-COE), Nagoya University, Japan
2008-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦The study of organic/inorganic interfaces by scanning tunneling microscopy (STM)✦The study of structure of nano-carbon materials by STM

Pengfei GUAN
Research Associate
E-mail: Miracle.fei@gmail.com
ACADEMIC:
2000 B.S. in Solid State Physics, Jilin University, P.R.China.
2003 M.S. in Condensed Matter Physics, Jilin University, P.R.China
2008 Dr. Materials Science, Central Iron & Steel Res. Inst. (CISRI), P.R.China.
PROFESSIONAL EXPERIENCE:
2003-2004
Visiting Student, Institute of Physics, Chinese Academy of Science, P.R.China
2008-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦Microcosmic mechanisms of physical and chemical properties in advanced materials

106Curriculum Vitae

Hiroki HIRAGA
Research Associate
E-mail: hiraga.hiroki@imr.tohoku.ac.jp
URL: http://www.kawasaki.imr.tohoku.ac.jp/

ACADEMIC:
2003 B.S. in Chemistry, Kanagawa University, Japan
2005 M.S. in Chemistry, Kanagawa University, Japan
2008 Dr. Sci., in Materials Science and Engineering, Tohoku University

PROFESSIONAL EXPERIENCE:
2008- present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦The study of coordination chemistry on functionalized oxide thin film

Kazumasa HORIGANE
Research Associate
E-mail: khorigane@imr.tohoku.ac.jp

ACADEMIC:
2002 B.S. in Physics, Aoyama-Gakuin University, Japan
2004 M.S. in Physics and Mathematics, Aoyama-Gakuin University, Japan
2008 Dr. Sci., in Physics and Mathematics, Aoyama-Gakuin University, Japan

PROFESSIONAL EXPERIENCE:
2004-2007
2008-present

Research Supporter for COE Program, Department of Physics and Mathematics, Aoyama
Gakuin University, Japan
Research Associate, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:
The Development of new materials in superconductor and the study of unusual cobalt oxides magnetism bymeans of neutron diffraction experiments.

107Curriculum Vitae

Satoshi IIKUBO
Research Associate

E-mail: iikubo.satoshi@imr.tohoku.ac.jp
ACADEMIC:
2000 B.S. in Physics, Nagoya University, Japan
2002 M.S. in Physics, Nagoya University, Japan
2005 Dr. Sci. in Physics, Nagoya University, Japan

PROFESSIONAL EXPERIENCE:
2002-2005
2005-2008
2008-present

JSPS Research Fellowship (DC), Japan
Post-doc., Quantum Beam Science Directorate, Japan Atomic Energy Agency, Japan
Research Associate, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:
Anomalous Hall effect, High-Tc Cu oxides, Superconductor, Magnetic excitation, Non-trivial magnetic
structure, Nano-materials, PDF analysis, Negative thermal expansion

Zhaofei LI
Research Associate
Email: zfli@sspns.phys.tohoku.ac.jp

ACADEMIC:
2000 B.S. in Chemistry & Molecular Engineering, Peking University, P.R.China
2005 Ph.D. in Chemistry & Molecular Engineering, Peking University, P.R.China

PROFESSIONAL EXPERIENCE:
2005-2007
Postdoctoral Researcher, Institute of Geology, Mineralogy & Geophysics,
Ruhr-University-Bochum, Germany
2007-2008
Postdoctoral Researcher, Department of Physics, Tohoku University
2008-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
The study of solid state nano-materials with chemical species confined in nano-sapces. And the study of
inorganic materials with exotic physical and chemical properties, especially superconductivity.

108Curriculum Vitae

Shantanu MADGE
Research Associate
E-mail: S.Madge.99@cantab.net
ACADEMIC:
1995 B.E. in Metallurgy, University of Pune, India
1999 M.E. in Metallurgy, Indian Institute of Science, India
2003 Ph.D in Materials Science & Metallurgy, University of Cambridge, UK
PROFESSIONAL EXPERIENCE:
1995-1997
Graduate Engineer, Tata Motors, India
2003-2005
Guest Scientist, Forschungszentrum Karlsruhe, Germany
2005-2006
Post-Doctoral Research Associate, Arizona State University, USA
2006-2008
Scientist D, ARC International, India
2008-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:
Development of newer bulk metallic glasses, fundamental studies of crystallisation in glasses, theirdeformation and the optimisation of their mechanical properties.

Akira MASAGO
Research Associate

E-mail: masago@wpi-aimr.tohoku.ac.jp
ACADEMIC:
1995 B.S. in Science, Kochi University, Japan
1997 M.S. in Science, Kochi University, Japan
2001 Dr. Engineering in Science, Osaka University, Japan

PROFESSIONAL EXPERIENCE:
2001-2005
2005-2008
2008-present

PD, ISIR-SANKEN, Osaka University, Japan
PD, Engineering, The University of Tokyo, Japan
Research Associate, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:
The theoretical study of physical phenomena in the scanning probe microscopy

109

Curriculum Vitae

Keisuke TOMIYASU
Research Associate
E-mail: tomiyasu@imr.tohoku.ac.jp

ACADEMIC:
1997 B.S. Waseda University, Japan
1999 M.S. Waseda University, Japan
2002 Dr. Sci., Waseda University, Japan
PROFESSIONAL EXPERIENCE:
2002-2005
Research Assistant, School of Science and Engineering, Waseda University, Japan
2005-2006
Postdoctoral Researcher, Neutron Science Laboratory, High Energy Accelerator
Research Organization, Japan
2006-2007
Postdoctoral Researcher, Institute for Materials Research, Tohoku University
2007-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦ Neutron scattering studies of magnetism, strongly correlated electrons, and methodology

Dong WANG
Research Associate
E-mail: wangdthu@wpi-aimr.tohoku.ac.jp

ACADEMIC:
2001 B.S. in Chemistry, Hebei University, P.R.China
2004 M.S. in Polymer Chemistry and Physics, Hebei University, P.R.China
2008 Ph.D. in Materials Science and Engineering, Tsinghua University, P.R.China
PROFESSIONAL EXPERIENCE:
2008
Research Scientist in Honeywell Specialty Materials Asia Technology Center, P.R.China
2008-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦ Nano-mechanical properties mapping of polymer nano-composites by atomic force microscopy✦ 3D-visularization of polymer processing by 3D transmission electron microscopy

110Curriculum Vitae

Zhongchang WANG
Research Associate
E-mail: zcwang@wpi-aimr.tohoku.ac.jp

ACADEMIC:
2001 B.S. in Materials Science, Anhui University of Technology, P.R.China
2004 M.S. in Materials Science, Chongqing University, P.R.China
2008 Ph.D. in Materials Engineering, The University of Tokyo, Japan
PROFESSIONAL EXPERIENCE:
2004-2008
Ph.D./Scientific Co-worker, The University of Tokyo, Japan
2008-Present Research Associate, WPI Advanced Institute for Materials Science, Tohoku University
CURRENT RESEARCH:
Quantitative analysis of a local atomic and electronic structure of a crystal interface and a grain boundary
through combination of a scanning transmission electron microscopy (STEM) or a high resolution
transmission electron microscopy (HRTEM) image with first principle simulation.

Daisuke WATANABE
Research Associate
E-mail: watanabe@mlab.apph.tohoku.ac.jp
URL: http://www.wpi-aimr.tohoku.ac.jp/en/index.html

ACADEMIC:
2003 B.S. in Applied Physics, Tohoku University
2005 M.S. in Applied Physics, Graduate School of Engineering, Tohoku University
2008 Dr. Eng. in Applied Physics, Graduate School of Engineering, Tohoku University
PROFESSIONAL EXPERIENCE:
2005-2008
JSPS Fellow, Graduate School of Engineering, Tohoku University
2008-present Research Associate, WPI Advanced Institute for Materials Research, Tohoku University
CURRENT RESEARCH:✦ Spin transfer phenomenon in nanoscale magnetic materials.
✦Microfabrication process for magnetic tunnel junctions and development of magnetoresistive random
access memory (MRAM)

111

Curriculum Vitae

Rui WEN
Research Associate
E-mail: ruiwen@atom.che.tohoku.ac.jp

ACADEMIC:
2000 B.S. in Physics, Hubei Normal University, P.R.China.
2005 M.S. Beijing Key Laboratory for Nano-Photonics and Nano-Structure,
Capital Normal University, P. R.China.
2008 Ph.D. in Chemistry, Chinese Academy of Sciences, P. R.China.

PROFESSIONAL EXPERIENCE:
2008-present

Research Associate, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:✦ Atomic-scale Etching Processes of Semiconductor Electrodes✦ Molecular Self-assembly on Electrode Surfaces

Feng WU
Research Associate
E-mail: fengwu@wpi-aimr.tohoku.ac.jp

ACADEMIC:
2003 B.S. in Metallurgy Science and Engineering, Central South University, P.R.China
2005 M.S. in Materials Physics and Chemistry, Chinese Academy of Science,
P.R.China
2008 Dr. Materials Physics and Chemistry, Chinese Academy of Science, P.R.China

PROFESSIONAL EXPERIENCE:
2008-present

Research Associate, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:
Half-metallic ferromagnetic and ferrimagnetic thin films with superior physical properties used in
spintronic devices (MRAM)112

Curriculum Vitae

Shinya YOSHIDA
Research Associate
E-mail: s-yoshida@mems.mech.tohoku.ac.jp

ACADEMIC:
2003 B.E. in Engineering, Tohoku University
2005 M.E. in Engineering, Tohoku University
2008 Ph.D. in Engineering, Tohoku University

PROFESSIONAL EXPERIENCE:
2008-present

Research Associate, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:
The study of scanning multiprobe data storage systems using conductive polymer as recording media.

Xuefeng ZHANG
Research Associate
E-mail: xfzhang@imr.tohoku.ac.jp

ACADEMIC:
2004 B.S. in Material Science and Engineering, Dalian University of Technology,
P.R.China
2008 Ph.D. in Materials Physics and Chemistry, Dalian University of Technology

PROFESSIONAL EXPERIENCE:
2008-present

Research Associate, WPI Advanced Institute for Materials Research, Tohoku University

CURRENT RESEARCH:✦ Nanocrystalline metals and aloys✦ Synthesis and characterization of the nanomaterials✦ Microwave absorption and electromagnetic response characteristics of magnetic nanoparticles

113Curriculum Vitae

Graduate students

Takayuki NARUMI
Research AssistantE-mail: narumi@athena22.ifs.tohoku.ac.jp

ACADEMIC:
2005 B.S. in Physics, Keio University, Japan
2007 M.E. in Nanomechanics, Tohoku University
present Ph. D candidate in Nanomechanics, Tohoku University
CURRENT RESEARCH:
We study the mechanisms of the glass transition theoretically. Although liquids regularly crystallize at themelting point, under rapid quench they can become super-cooled liquids below the melting point, followed
by glasses at the glass transition temperature. In these days, the bulk metallic glasses (BMGs) gather
engineering attention as well as scientific one. The understanding of the mechanisms of the glass transition
leads us to put super-cooled liquids to practical use, to produce more stable BMGs, and so on.
In order to reveal the mechanisms, we focUSAttention on the dynamical heterogeneity appeared in supercooled liquids slightly above the glass transition temperature. We simulate super-cooled liquids for a simple
model by means of molecular dynamics methods and put the results in perspective of statistical physics.

Varu RANI
Research AssistantE-mail: chauhan@mail.tagen.tohoku.ac.jp

ACADEMIC:
2002 B.S. in Chemistry, Ch. Charan Singh University, India
2004 M.S. in Chemistry, Ch. Charan Singh University, India
2007 M.Tech. in Advanced Chemical Analysis, Indian Institute of Technology, India
2008-present Ph. D candidate in Chemical Engineering, Institute of Multidisciplinary Research in
Advanced Materials (IMRAM), Japan
CURRENT RESEARCH:
This is related to the synthesis of the nanoparticles using super critical fluid technology towards biomedical
applications. Organic inorganic hybrid nano materials can be synthesized by using the super criticalconditions and the particles can be designed so as to be perfectly dissolved into water, solvents or polymers.
These hybrid nano materials shows unique properties which can be used in biomedical applications like
multi imaging probe and super Drug Delivery System (DDS).

114

Curriculum Vitae

Graduate students

Ryota SHIMIZU
Research AssistantE-mail: shimizu@chem.s.u-tokyo.ac.jp

ACADEMIC:
2006 B.S. in Science, The University of Tokyo, Japan
2008 M.S. in Science, The University of Tokyo, Japan
2008-present Ph. D candidate in Chemistry, The University of Tokyo, Japan
CURRENT RESEARCH:✦Oxide surface✦ Scanning tunnelling microscopy / spectroscopy

Jungwoo YOO
Research AssistantE-mail: jw-yoo@mail.tagen.tohoku.ac.jp

ACADEMIC:
2006 B.S. in Material Science and Engineering, Pohang University of Science andTechnology, Korea
2008 M.S. in Material Processing, Tohoku University,
2008-present Ph.D candidate in Chemical Engineering, Tohoku University
CURRENT RESEARCH:✦ Bio-imaging with quantum dots
✦Synthesis of organic-inorganic hybrid nanoparticle✦ Thermodynamical behavior of nanoparticles
In order to stable dispersion of nanoparticles, our laboratory suggested organic-inorganic hybrid
nanoparticle, i.e., surface modification of inorganic core by organic surface modifier. We haveestablished the in-situ supercritical hydrothermal synthesis of organic surface modified CeO2
nanoparticles. These hybrid CeO2 nanoparticles show high solubility for organic solvents, e.g., THF,
CHCl3 and cyclohexane. The solution doesn’t show any aggregation even at the high concentration of
hybrid nanoparticles. Furthermore, the particles show ‘reversible solve and precipitate behavior’ by
cyclic cooling, heating, diluting and concentrating of the solution. These results suggest that the behaviorof our hybrid nanoparticles in good solvents is more similar with that of nonpolar molecules than that ofsolid core particles and powders. In other words, it is quite similar to phase behavior of a solute-solvent
binary system.
In the present study, we investigate the dispersion behavior of the hybrid CeO2 nanoparticles in organic
solvents and suggest a new thermodynamic system as the hybrid nanoparticle-solvent binary system.

115

Adjunct Professors

Curriculum Vitae of Adjunct Professor

Hans-Jörg FECHTPRIMARY AFFILIATION:
Chaired Professor and Director
Institute of Micro and Nanomaterials,
Ulm University
Albert-Einstein-Allee 47
D-89081 Ulm, Germany
E-mail: hans.fecht@uni-ulm.de
ACADEMIC:
1981

B.S. in Materials Science, Univ. Saarbrücken, Germany

1984

Ph.D. in Materials Science, Univ. Saarbrücken, Germany

PROFESSIONAL EXPERIENCE:
1984-1987
Post-Doctoral Research Associate, Department of Materials Science and Engineering,
University of Wisconsin-Madison, USA
1987-1990
Senior Research Associate, Department of Materials Science, California Institute ofTechnology, USA
1990-1993
Professor of Metalphysics (C-3), University of Augsburg, Germany
1993-1997
Chaired Professor of Materials Science, Technical University Berlin, Germany
1997-present Chaired Professor of Materials Science and Engineering
Director Kompetenzzentrum “Nano- and MicroMaterials” University of Ulm, Germany
2001-present Senior Scientist / Group leader INT-FZK, Karlsruhe
RECOGNITION:✦Fellow of Max-Kade-Gesellschaft (New York) (1984)✦G.W. Leibniz-Award (Deutsche Forschungsgemeinschaft, DFG) (1998)✦Pioneer of Nanotechnology (Deutsche Bank AG) (2003)✦Innovation Award of German Engineering Foundation VDI (2004)✦Head of Nanomaterials activity of DGM (2005)✦Member of Board ESF European Space Science Council (2006)✦Overseas Professor, Anna University Chennai, India (2007)✦Panel Chair Materials Science of ESSC at European Science Foundation (2008)✦Chairman of Board, High Tech Alliance under the auspices of BMBF (2008)119Curriculum Vitae of Adjunct Professor

Chain. T. LIU
PRIMARY AFFILIATION:
Professor and Distinguished Research Professor
Department of Materials Science and Engineering,
The University of Tennessee
Knoxville, TN 37996-2200, USA
Email: liuct@ornl.gov
URL: http://www.ms.ornl.gov/index.shtml
ACADEMIC:
1960

B.S. in Mechanical Engineering, National Taiwan University, Taiwan

1964
1967

M.S. in Materials Science, Brown University, USA
Ph. D. in Materials Science, Brown University, USA

PROFESSIONAL EXPERIENCE:
1967-1982
Research Staff Member, Oak Ridge National Laboratory (ORNL), USA
1983-2005
Group Leader, Oak Ridge National Laboratory (ORNL), USA
1985-1997
Corporate Fellow & Senior Corporate Fellow, Oak Ridge National Laboratory (ORNL), USA
2005-present Professor & Distinguished Research Professor, University of Tennessee, USA
CURRENT RESEARCH:
Fundamental and applied research on plastic deformation and fracture of a variety of advanced materials(refractory alloys, precious metal alloys, superalloys, bulk amorphous alloys, ordered intermetallic alloys, andshape-memory alloys); glass forming ability and alloy design of bulk metallic glasses, thermodynamics andphase relationship; alloying behavior; alloy design of high-temperature structural materials; microstructure andproperty correlation; materials processing and characterization.
RECOGNITION:✦American Society for Metals, Fellow (1984)✦U.S. Department of Energy, E. O. Lawrence Award (US president Award) (1988)✦Editor, Journal of Intermetallics (1992)✦The Minerals, Metals and Materials Society (TMS), Fellow (1994)✦Brown Engineering Alumni Medal Award, Brown University (1998)✦Acta Metallurgic Inc., Acta Metallurgica Gold Medal (2001)✦Information Sciences Institute, one of 1000 Most Cited Physicists (2001)✦Information Sciences Institute (ISI), Highly Cited Researcher in Materials Science (2003)✦National Academy of Engineering (NAE), Member (2004)✦The Word Technology Network, Fellow (2003)✦Governor of the Acta Materials Board, ASM (2005)✦Chinese Academy of Engineering (CAE), Foreign Member (2006)✦Honorary Member of Japan Institute for Metals (JIM) (2006)

120

Curriculum Vitae of Adjunct Professor

John H. PEREPEZKOPRIMARY AFFILIATION:
Professor
Department of Materials Science and Engineering,
University of Wisconsin-Madison
1509 University Avenue
Madison, WI 53706, USA
E-mail : perepezk@engr.wisc.edu

ACADEMIC:
1967

B.S. in Polytechnic Institute of New York Brooklyn, USA

1968

M.S. in Polytechnic Institute of New York Brooklyn, USA

1973

Ph.D. Carnegie-Mellon University Pittsburgh, USA

PROFESSIONAL EXPERIENCE:
1968-1970
Assistant Scientist, Fundamental Research Laboratory, U.S. Steel Corporation, USA
1973-1974

Post-doctoral Research Fellow, Carnegie-Mellon University, USA

1975-1978

Assistant Professor, Department of Metallurgical and Mineral Engineering, University of
Wisconsin-Madison, USA

1978-1981

Associate Professor, Department of Metallurgical and Mineral Engineering, University of
Wisconsin-Madison, USA

1981-2000

Professor, Department of Materials Science and Engineering, University of
Wisconsin-Madison, USA

2000-Present

IBM-Bascom Professor, Department of Materials Science and Engineering, University of
Wisconsin-Madison, USA

CURRENT RESEARCH:
Study of the mechanism, kinetics and thermodynamics of phase transformations, nucleation duringsolidification, amorphous metals, rapid solidification processing, metastable phases, intermetallic alloys, hightemperature alloys, composite materials and the structure and characteristics of interfaces.
RECOGNITION:✦Exceptional Creativity Award NSF (1982-83)✦University of Wisconsin Polygon Outstanding Professor Award (1983, 1985, 1989)✦American Society for Metals-Milwaukee Chapter Outstanding Service Award (1988)✦Crystal Growth Society - Pittsburgh Chapter Outstanding Research Award (1989)✦Senior Research Prize Award - Alexander von Humboldt Stiftung (Germany) (1996)✦Bruce Chalmers Award - TMS - (1997)✦Editor for Scripta Materialia (2001-2006)✦Senior Research Award – ISMANAM Conference-(2004)✦Fellow Award-TMS-(2004)✦National Academy of Engineering- (2004)✦Visiting Researcher Award – Japan Society for the Promotion of Science – (2005)

121

Curriculum Vitae of Adjunct Professor

Simon P. RINGERPRIMARY AFFILIATION:
Professor and Director
Electron Microscope Unit (EMU),The University of Sydney
NSW 2006, Australia
Phone: 02 9351 2351
Fax: 02 9351 7682
E-mail: s.ringer@usyd.edu.au
ACADEMIC:
1985 B.S. in Metallurgy, The University of South Australia, Australia
1991 Ph.D. in Materials Science and Engineering , The University of New South Wales, Australia
PROFESSIONAL EXPERIENCE:
1991-1993
Research Fellow, Department of Materials Engineering, Monash University, Australia
1994-1995
Research Associate, Institute for Materials Research, Tohoku University
1995-1996
Japan Society for the Promotion of Science Postdoctoral Fellow, Institute for Materials
Research, Tohoku University
1997
Acting College Head, Richardson Hall, Monash University, Australia
1996-1997
Deputy College Head, Richardson Hall, Monash University, Australia
1996-1998
Lecturer, Department of Materials Engineering, Monash University, Australia
1998-2001
Senior Lecturer, Department of Materials Engineering, Monash University, Australia
2001-2004
Associate Professor and Director, Electron Microscope Unit (EMU), The University of Sydney,
Australia
2001-present Executive Director and CEO of NANO
2004-present Director, NANO Analytical Pty Ltd (ABN 112 219 799)
CURRENT RESEARCH:
Phase Transformations, Nanomaterials, Engineering Alloys, Structure/Property Relationships,
Materials Characterisation, Al-Alloys, Magnetic Materials, Nuclear Materials, HSLA Steels,
Welding, Transmission Electron Microscopy, Energy Dispersive X-ray Analysis,
Electron Energy Loss Spectroscopy, Three Dimensional Atom Probe Field Ion Microscopy, Calorimetry,
Mechanical Testing, Programming and Software Applications and Development in the UNIX,
Mac/PC Environments.
RECOGNITION:✦Awarded ARC Linkage Industry Research Fellowship (2003)✦Elected as Fellow of the Institution of Engineers Australasia (2001)✦City of Monash Business Awards Nominee; Waverley City Council, Victoria (2000)✦Top 10 reviewer award for review services to the journal Acta Materialia (Elsevier)(1999)✦42nd International Field Emission Symposium, Madison, WI, USA, Most Outstanding
Poster Award (1995)✦Awarded Japan Society for the Promotion of Science Research Fellowship (1993)✦Alcan Bicentennial Scholarship, The University of New South Wales, Australia (1990)✦Doktorand Stipendium’, Luleå University of Technology, Sweden (1988)✦Australian Welding Research Association, Sir William Hudson Memorial Award Winner (1987)

122

Curriculum Vitae of Adjunct Professor

Akira SAKAIPRIMARY AFFILIATION:
Professor
Department of Materials Science and Engineering,
Kyoto University
Yoshida-Honmachi, Sakyo-ku,
Kyoto, 606-8501 Japan
E-mail: sakai-akira@z06.mbox.media.kyoto-u.ac.jp
ACADEMIC:
1974 B.S. in Physics, The University of Tokyo, Japan
1976 M.S. in Physics, The University of Tokyo, Japan
1981 Ph.D. Physics, The University of Tokyo, Japan
PROFESSIONAL EXPERIENCE:
1981-1987
Research Associate, Institute for Solid State Physics, The University of Tokyo, Japan
1983-1984
Resident Visitor, AT&T Bell Laboratories, Murray Hill, USA
1987-1989
Research Scientist, ULSI Research Center, TOSHIBA Corporation, Japan
1989-1994
Chief Scientist, ULSI Research Center, TOSHIBA Corporation, Japan
1992-2002
Professor, Mesoscopic Materials Research Center, Faculty of Engineering, Kyoto University,Japan
2002-2007
Professor, International Innovation Center, Kyoto University, Japan
2007
Professor, Innovative Collaboration Center, Kyoto University, Japan
2007- 2008
Professor, Graduate School of Engineering, Kyoto University, Japan
2008-present Professor, Department of Materials Science and Engineering, Kyoto University, Japan
CURRENT RESEARCH:✦Atomic and molecular contacts✦Nano-structured materials✦Surface physics

123Curriculum Vitae of Adjunct Professor

Koji KAJIMURAPRIMARY AFFILIATION:
Vice President
Japan Society for the Promotion of Machine Industry
3-5-8 Shibakoen, Minato-ku, Tokyo 105-0011, Japan
E-mail: kajimura@tri.jspmi.or.jp
ACADEMIC:
1965

B.E. in Electric Engineering, Osaka University, Japan1967

M.E. in Physics, Osaka University, Japan1972

Dr.Sci., The University of Tokyo, Japan

PROFESSIONAL EXPERIENCE:
1968-1998
Ministry of Economy, Trade and Industry, Electrochemical Laboratory, Japan
1988-1998
Chairperson of Superconductivity Promotion committee, National Institute of Advanced
Industrial Science and Technology, Ministry of Economy, Trade and Industry, Japan
1998-1999
Director of National Institute of Advanced Industrial Science and Technology, Japan
1992-1999
Professor, Tsukuba University, Japan
1999-2001
Director of Agency of Industrial Science and Technology, Ministry of International Trade andIndustry, Japan
2001-2008
Research Supervisor in Basic Research Programs, Japan Science and Technology Agency
2006-Present Member of executive board in Science Council of Japan124

Curriculum Vitae of Adjunct Professor

Masahiro IRIE
PRIMARY AFFILIATION:
Professor
Department of Chemistry,
Rikkyo University
Nish-Ikebukuro 3-34-1, Toshima-ku
Tokyo, 171-8501, Japan
E-mail: iriem@rikkyo.ne.jp
ACADEMIC:
1966

B.E., Kyoto University, Japan1968

M.E., Kyoto University, Japan1974

Ph.D., Osaka University, Japan

PROFESSIONAL EXPERIENCE:
1974-1978
Lecturer, the Institute of Scientific and Industrial Research, Osaka University, Japan
1978-1988
Associate Professor, the Institute of Scientific and Industrial Research, Osaka University, Japan
1988-1996
Professor, Institute of Advanced Material Study, Kyushu University, Japan
1996-2007
Professor, Graduate School of Engineering, Kyushu University, Japan
2007-Present Professor, Rikkyo University, Japan
RECOGNITION:✦Award of the Society of Polymer Science, Japan (1988)✦Award of the Japanese Photochemistry Association (1993)✦Vinci d’excellence “Science pour l’art” (LVMH) (1995)✦Docteur Honoris Causa of University of Bordeaux 1 (2003)✦Chemical Society of Japan Award (2004)✦Mukai Award (Tokyo Ohka Foundation for Promotion of Science and Technology) (2007)✦The Purple Ribbon Medal (2007)125

Curriculum Vitae of Adjunct Professor

Kohei UOSAKIPRIMARY AFFILIATION:
Director
Collaborative Research Center
for Molecular and System Life Sciences,
Hokkaido University
N10W8, Kita-ku, Sapporo 060, Japan
E-mail: uosaki@pcl.sci.hokudai.ac.jp
ACADEMIC:
1969

B.E. in Applied Chemistry, Osaka University, Japan1971

M.E. in Applied Chemistry, Osaka University, Japan1976

Ph.D. in Physical Sciences, The Flinders Univ. of South Australia, Australia

PROFESSIONAL EXPERIENCE:
1978-1980
Research Officer, Inorganic Chemistry Laboratory, Oxford University
1980-1981
Assistant Professor, Department of Chemistry, Hokkaido University, Japan
1981-1990
Associate Professor, Department of Chemistry, Hokkaido University, Japan
1990-1995
Professor , Department of Chemistry, Faculty of Science, Hokkaido University, Japan
1995- Present Professor, Division of Chemistry, Graduate School of Science, Hokkaido University, Japan
1999-2000
Advisor to President, Hokkaido University, Japan
2000-2002
Director, Catalysis Research Center, Hokkaido University, Japan
2000- 2002
Senate, Hokkaido University, Japan
2005-2006
Chairman, Division of Chemistry, Hokkaido University
2007-Present Concurrent Professor, College of Chemistry and Chemical Engineering, Nanjing University,
P.R. China
2007-Present Director, Collaborative Research Center for Molecular and System Life Sciences, Hokkaido
University

RECOGNITION:✦Science Award, The Electrochemical Society of Japan (1993)✦Best Paper Award, The Electrochemical Society of Japan (2000)✦Fellow, IUPAC(2002)✦Fellow, The Royal Society of Chemistry, UK (2005)✦Distinguished Alumni Award, The Flinders University of South Australia, (2006)126

Curriculum Vitae of Adjunct Associate Professor

Takanori FUKUSHIMA
PRIMARY AFFILIATION:
Laboratory Head
Functional Soft Matter Engineering Laboratory,
Advanced Science Institute, RIKEN
2-1 Hirosawa Wako, Saitama 351-0198, Japan
Phone: +81-48-462-1111 (ext. 6345) / Fax: +81-48-467-8104
E-mail: fukushima@riken.jp
ACADEMIC:
1992 B.S. in Science, Tohoku University
1994 M.S. in Science, Tohoku University
1999 Ph.D in Science, Tohoku University
PROFESSIONAL EXPERIENCE:
1995-1996 Research Fellowship for Young Scientist, Japan Society for the Promotion of Science, Japan
1996-2001 Research Assistant, Graduate School of Science, Tohoku University
2001-2003 Researcher, ERATO Nanospace Project, Japan Science and Technology Corporation (JST), Japan
2004-2007 Group Leader, ERATO Nanospace Project, Japan Science and Technology Agency (JST), Japan
2007-present Laboratory Head, Advanced Science Institute, RIKEN, Japan
2006-present Associate Professor, School of Engineering, The University of Tokyo, Japan
RECOGNITION:✦The Society of Polymer Science Japan: Wiley Award (2005)✦The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science andTechnology, Japan: The Young Scientists’ Prize (2008)

Yasushi MORITAPRIMARY AFFILIATION:
Associate Professor
Department of Chemistry,
Graduate School of Science, Osaka University
Machikaneyama 1-1, Toyonaka, Osaka, 560-0043 Japan
Phone: +81-6-6850-5393 / Fax: +81-6-6850-5395
E-mail: morita@chem.sci.osaka-u.ac.jp
ACADEMIC:
1983

B.S. in Chemistry, Nagoya University, Japan

1985

M.S. in Chemistry, Nagoya University, Japan1989

Ph.D., Nagoya University, Japan

PROFESSIONAL EXPERIENCE:
1989-1990
Post-doctoral fellowship, Harvard University, USA
1990
Research Associate, Institute for Molecular Science, Japan
1993
Assistant Professor, Osaka University, Japan
2003
Lecturer, Osaka University, Japan
2004-present Associate Professor, Osaka University, Japan
2002-2006
Researcher, “Synthesis and Control” project in Precursory Research for Embryonic Scienceand Technology (PRESTO), JST, Japan
127

WPI-IFCAMWPI-IFCAMInternational Frontier Center for Advanced Materials (IFCAM) was inaugurated in Institute forMaterials Research (IMR), Tohoku University, in October 2001 to function, simply stated, as theworld-first “materials science think-tank.” With wise steering by past directors, IFCAM has been
performing well in its mission until now by 1) bringing in many world-renown researchers to IMR
in the greater field of materials science/engineering, 2) enlightening / encouraging young scientists,
post-doctoral fellows and graduate students by organizing and supporting workshops/summer
schools, and 3) establishing and coordinating IFCAM branch offices around the world, including
those in Cambridge University, Harvard University, Stanford University, and Institute of Physics,
P.R. China.
We were also so fortunate to have had a government initial-equipment fund in 2002 to acquire
several advanced tools, such as 3-dimention atom-probe tomography (3-D AP) and low energy
electron microscope (LEEM). With untiring effort of able faculty members and their staff / graduate
students, the LEEM program of IFCAM, for instance, has quickly become one of the most active
and successful research centers in the world.
Realizing that IFCAM and newly established WPI-AIMR have essentially the same mission:
namely, further promote international collaboration and cooperation in innovative research on
advanced materials on a global bases, IFCAM was transferred from IMR to WPI-AIMR, effectiveof April 2008.
Briefly stated, WPI-IFCAM has following function and service.
. Visiting Professorship. Workshops / summer schools. Visiting Professorship
Qualified researchers who may be interested in IFCAM visiting professorship should first contact
the WPI principal investigator(s) of the related research fields. Your contact PIs will initiate thefurther process to materialize the joint research.
(1) Tenure: For a period of minimum one month to a maximum of 3 months.
(2) Financial: The salary varies, depending on the qualifications, based on the Tohoku University
regulations. Roughly speaking, “full professor” receives Y600,000 per month and “Associate
Professor” receives Y500,000 per month.
. Workshops / summer schools
WPI-IFCAM will financially support the workshops and summer schools, if the scientific aims arealong the WPI-AIMR missions. For more information, please contact WPI Administrative Office.

131

132

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WPI Activity Report of Prof. Lu-Chang Qin
April 14 – June 13, 2008
Host: Professor Mingwei Chen
My research activities during my two month stay (14 April – 13 June 2008) at the Advanced
Institute for Materials Research (WPI) on the Katahira Campus of Tohoku University, hosted byProfessor Mingwei Chen, involved two areas: (1) Mechanical properties of Fe-Cu alloys studied byin situ synchrotron x-ray diffraction under hydrostatic pressure and (2) Structural analysis of carbon
nanotubes by electron microscopy techniques.
In situ High Pressure X-Ray Diffraction of Fe-Cu Alloys:
In this study, we studied the mechanical and structural properties of two Fe-Cu alloys
produced by ball milling. The endothermic process with a positive heat of mixing of the immiscible
bcc-Fe and fcc-Cu crystals in the formation of an alloy by ball milling is of fundamental interest inmaterials science. The purpose of this study is to examine the changes of bulk modulus and thestructural characteristics of the bcc-Fe when a small amount of fcc-Cu is added to form an alloy byball milling. Using materials provided by collaborators, we have prepared three samples (Fe,
Fe0.9Cu0.1 and Fe0.8Cu0.2) for in situ investigations to measure the bulk moduli of the Fe-Cu alloys
using the dedicated synchrotron high pressure beam line at the Photon Factory in Tsukuba, Ibaraki.
During the course of this study, we examined the changes of the lattice constants of eachcomposition of the Fe-Cu alloys produced by ball milling and have collected powder x-ray
diffraction data at various values of hydrostatic pressure up to 10 GPa. Preliminary examinations of
the experimental data indicate that there is a noticeable change of the bulk modulus when theconcentration of Cu elements is increased, even by 10%. More detailed analysis of the experimental
data is underway and a manuscript summarizing the results for publication is in preparation.
Electron Microscopy Study of Carbon Nanotubes:
In the study of carbon nanotubes, it is of vital importance to know the exact atomic structure of
the nanotube under examination when the relationship between structure and properties is soughtfor both fundamental understanding and eventual industrial applications as envisaged in thenanoelectronics devices. While it is now an established method to determine the chirality via chiralindices (n,m) of carbon nanotubes using electron diffraction, the information on the handedness is
usually lostin the electron diffraction intensities. The objective of this project is to utilize the electron
holographic and electron tomographic techniques to obtain structural information on the chirality
including the absolute handedness of carbon nanotubes using the state-of-the-art 300 kV
Cs-corrected high-resolution transmission electron microscope (FEI-Titan). Unfortunately, due tounavailability of this microscope, we have not been able to collect usable experimental data as
originally planned during my stay at WPI. In collaboration with Professor Chen and Dr. Takeshi
Fujita, we will look for future opportunities to resume this experiment to tackle this problem when
the high-performance TEM becomes operational and available.
During my stay at Tohoku University, I also had the opportunity to visit Professor Katsumi
Tanigaki’s laboratory (Laboratory of Solid State Nanonetwork Materials) in the Department andPhysics on the Aobayama Campus and presented a seminar on “Determination of the Chirality of
Carbon Nanotubes by Electron Diffraction”. Potential and future collaborations with Professor
Tanigaki and his group on the studies of the iron-based layered La(O1-x Fx) FeAs superconductors
and nanowires were also discussed during my visit.
Last but not the least, I wish to thank Professor Mingwei Chen and WPI for offering me theopportunity to visit WPI and Tohoku University. The excellent support provided by theadministrative staff of WPI, and in particular, Ms. Mariko Onodera (Administrate Assistant of theChen Laboratory), has made my brief stay in Sendai a rewarding experience.

133

WPI Activity Report of Prof. T.G. Nieh
July 10 – August 17, 2008
Host: Professor Mingwei Chen
The purpose of my stay at WPI as a visiting professor was to study the mechanical properties ofnanoporous (np) metals using nanoindentation, in particular using the newly-purchased hightemperature nanoindenter at WPI. Nanoporous metals are anticipated to be used for novel MEMS
devices. These np-devices, sometimes, experience temperature spike which may cause significant
softening and even spontaneous failure. Several room temperature nanoindentation experiments
have been carried out on np-Au, however, high-temperature mechanical response of np-Au has not
yet been investigated. This is primarily attributed to the fact that samples are generally small for
conventional tension or compression experiments. Furthermore, a high temperature testing
platform is unavailable. Therefore, my study includes both room temperature and elevatedtemperatures.
In the course of our study, we encountered several technical challenges associated with using
the equipment. With the high accuracy and resolution (< nm), a tight and sustaining temperature
control is always necessary in order to minimize the thermal drift of the nanoindentation instrument,
especially during a long-time experiment, even at room temperature. The conventional hightemperature adhesive often used for mounting macroscopic specimen (~mm) is inappropriate forour miniature np-Au specimens. The texture of high-temperature adhesive is simply too coarse tohold firmly the np-samples. A mechanical/magnetic fixture is being designed to overcome thisproblem. We also modified the sample mount device because the vendor’s design blocks themoving of indenter tip toward the testing sample and this can cause major damage of the indenter
head.
Despite the above difficulties, a number of experiments have been or are being conducted andthey are briefly described as follows.
1. Professor Chen’s group has fabricated nanoporous Au (np-Au) with the smallest pore size.
Thus, nanoindentation of np-Au with different ligament (or pore) sizes was conducted at room
temperature, to look for a possible breakdown of the length scale.
2. Nanoindentation creep of np-Au (and in parallel, the microcompression of np-Au pillars
fabricated by focus ion beam method) at non-ambient temperatures are being carried out toinvestigate the thermomechanical properties at elevated temperatures.
3. Nanoindentation of nanoporous noble metals, including np-Au, Pt, and Pd, are to be conducted.
Professor Chen’s group is the only group who can fabricate these samples from bulk metallic
glasses. This study is to summarize the general behavior of fcc np-metals and to extend/modify
the scaling law of Gibson-Ashby equations.
4. There are two practical ways to measure the strain rate sensitivity of a material using thenanoindentation method. One is to apply different indentation strain rates, and the other is toemploy the load change technique during nanoindentation creep.
With the assistance of Dr. Dan, we have completed the nanoindentation creep of np-Au at room
temperature and are currently analyzing the data. Considering the nanometer-scale ligament andgrain sizes, thus a short diffusion distance, we believe the creep mechanism is diffusional, withsurface diffusion as the rate controlling mechanism. I anticipated to publishing at least three journal
articles using the experimental results obtained. This will place Tohoku U. in the leading positionin the understanding of the mechanical behavior of np-metals.
Finally, I would like to express my sincere appreciation to Professor Mingwei Chen and every
member in his group for their help, especially Dr. Deng Pan’s technical support and Ms. Mariko
Onodera’s administrative assistance.

134

WPI Activity Report of Prof. Hongwei Sheng
July 1– August 25, 2008
Host: Professor Mingwei Chen
During Prof. H.W. Sheng’s visit to WPI from July 1, 2008 trough Aug. 26, 2008, he has beenworking on topics related to the current research at WPI, in particular, the investigation of
atomic-level structure of Zr-Cu-Ag bulk metallic glass (BMG) and the deformation mechanism of
BMGs. More specifically, by using computer simulation, he has committed himself to the following
topics:1. Development of high-fidelity interatomic potentials for three multi-component BMG
forming alloy systems: Zr-Cu-Ag, Zr-Cu-Al-Ag, and Pd-Ni-P. The development ofhigh-accuracy and high-transferability semi-empirical potentials for multi-component
systems has been known notoriously difficult, evidenced from the fact that there exist few
interatomic potentials, if not none, in literature to study the many-body effect of complex
metallic systems. Following an energy-landscape fitting scheme, he first produced large
sets of reference states by performing extensive ab initio simulations. Included in the
database for potential fitting are atomic configurations that cover large phase space of thesystems. For example, for the Zr-Cu-Ag system, around 600 configurations have been
generated. The final interatomic potentials, employing the embedded atom formalism,
were developed by fitting the pre-defined energy landscape. The finalized potentials werethen verified and validated against ab initio MD data. More validations involving structure
characterization, such as high-energy XRD and EXAFS will be considered in the future. Theinteratomic potentials as developed will have many implications and great applicability;
more computational work is currently under way.
2. Molecular dynamics study of the Zr-Cu-Ag system. By using the newly developed
interatomic potentials, the glass formation of the Zr-Cu-Ag system was systematicallystudied. The atomic structure of the ZrCuAg metallic glass resulting from large-scale MD (>8,000 atoms) were characterized, atomic packing details revealed. The structural features of
the computer-generated ZrCuAg BMGs are consistent with the recent findings of Dr. Fujitathat Ag atoms tend to form lone pairs and strings in Ag-lean compositions, (e.g., Ag < 10at.%). It is also found that the spatial extension and the connectivity of Ag-Ag pairs change
as functions of cooling rates and alloy compositions. When the concentration of Ag reaches
as high as 20 at.%, atomic segregation of Ag on the nano-meter scale has been identified.
The results will be further corroborated and explored by using synchrotron X-ray scattering
to be conducted at SPRING-8. Our MD simulation on the ZrCuAg system complements theexperimental work done at WPI.
To investigate the structural origin of the greatly enhanced glass forming ability of the
ZrCuAg system, slow dynamics of the supercooled liquids has been studied. While dynamic
heterogeneity of the supercooled liquids has been identified, structural analysis of the role of
Ag in the dynamically immobile regions has yet to be performed. More computational workin this direction is expected.
3. Large-scale computer simulation of the deformation of BMGs. Deformation mechanisms
of BMG remain largely unresolved so far. One of the puzzles lies in how the sample size
determines the plasticity as well as shear-banding of BMGs. To this end, by taking
advantage of the unique supercomputing capability at WPI, Prof. Sheng has attempted thefirst ever computer experiments on the mechanical behavior of “real” BMG samples, herein,
ZrCuAg, using ~20 million atoms (corresponding to sample size of 50 nm x 50nm x 100
nm). Also studied are the mechanical behavior of small samples, where the size varies
from 5~10 nm in diameter. It has been found that those small samples (~10 nm) undergo
uniform deformation under mechanical loading. During the deformation, a newphenomenon of atomic segregation /clustering was found. For the 20 million-atom sample,
the deformation process on the supercomputer is still in progress, and no conclusive results
135can be reached yet.
Last but not least, Prof. Sheng has worked together with researchers (students and postdocs) at
WPI, familiarized them with concepts in computational materials science, and taught themcomputational techniques to deal with various problems. During several tutorials given to them, theresearchers were able to learn how to visualize and analyze computational data, how to build
semi-empirical potentials from first-principle calculations. Prof. Sheng has worked them through anumber of computational packages, varying form ab initio calculations (VASP, WIEN2k) toclassical molecular dynamics (lammps) to physical property evaluation (e.g. phonon calculations).
He has also helped them to practice on in-house structural analysis and X-ray analysis codes, which
will greatly facilitate their future work on high-energy X-ray diffraction.
In summary, Prof. Sheng has mainly worked on computer simulation of bulk metallic glasses
during his visit at WPI. While some publishable preliminary results have been obtained, he expects
to use more time to iron out the details and hopes to continue the collaboration with WPI (Prof.
M.W. Chen) after his returning to the US. Some scientific papers will be written and dissimilated totechnical journals such as APL.

136

WPI Activity Report of Prof. Feng
July 2, 2008 – August 30, 2008
Host professors: Prof. Ming-wei Chen, Prof. Sadamichi Maekawa
During my stay at IFCAM, I have collaborated with local groups, especially Prof. Min-wei
Chen’s group, on various projects, which are listed in the following.

5.

1.

Inelastic x-ray scattering (IXS) experiments on nanoporous gold film. The size effects on the
Plasmon dispersion of confined systems is one of the active subjects in the field ofplasmonics. During my stay, I conducted IXS experiments at Spring8 on nanoporous gold
film samples, which were provided by Dr. Lang in Prof. Chen’s group. The pore sizes were
5nm, 10nm, 20nm. During the experiments, we have observed the Plasmon dispersion.
Because the signal is quite weak, we decide to grow much thicker samples, and will continue
the measurements in the next beamtime.

2.

Collaboration on the newly discovered Iron based high temperature superconductors. Mygroup has succeeded in synthesizing NdO1-xFxFeAs, BaFe2As2, Ba1-xKxFe2As2 samples.
During my stay, Prof. M. W. Chen and Dr. L. Zhang at IMR has conducted XRD, Raman,
EELS, EDX, TEM experiments on these samples, and obtained interesting results. I myself
have conducted photoemission measurements on these samples at UVSOR, and HiSOR
synchrotrons in Japan. I have helped with data analysis and interpretation. We set up a
discussion session with Prof. Maekawa, Dr. Mori, and Prof. Toyama on these data. As
results of this collaboration, Prof. Chen has submitted a research proposal to JST (Prof.
Maekawa and myself as co-PI). Two manuscripts have been written and will be submitted toacademic journals soon. We will continue the collaborative research along this line in theyears to come.

3.

Collaboration on the electronic structure of BiBaKCoO. BiBaKCoO is a kind of misfit
structured system with a highly strained interface. We have conducted photoemission
measurements and found some very interesting charge transfer across the internal oxideinterface. However, since the oxygen nonstoichiometry at the interface will directly affectthe electronic structure, it is unclear the charge transfer is due to doping or strain. In order todetermine the oxygen concentration, Prof. Chen has conducted WDS measurements on
BiBaKCoO, and provided the critical data of oxygen concentration, which helped me tointerpret the measured electronic structure.

4.

Setting up collaboration on Photoemission measurements of various bulk metallic glasses(BMG). I have learnt about BMG during my visit. It is a new field to me, and I am quite
fascinated by some of the physics there, and interested to combine my specialty ofphotoemission spectroscopy with BMG. Prof. Chen, Nieh, Sheng and I had a lot of
discussion on these materials. Prof. Chen has provided me samples of several BMG’s, wewill conduct photoemission measurements soon.
Setting up more collaborations with other IMR professors. Prof Maekawa has helped to
introduce Prof. Y. Iwasa to me. Prof. Y. Iwasa and I will collaborate on measuring theelectronic structure of ZrNCl compounds synthesized by Prof. Y. Iwasa’s group.

During the period of my stay at IFCAM, I also had the opportunity to interact with Prof. Shimada at
Hiroshima university, and with visiting Professors H. Sheng, and T. G. Nieh.

137

This visit at IMR is really a fruitful one, I have enjoyed the collaboration with several groups here,
particularly Prof. Ming-wei Chen and his group.
Finally, I would like to thank WPI, IMR, Tohoku University and Prof. M. W. Chen and Prof. S.
Maekawa for giving me this opportunity. I am very grateful for their kindness and hospitality
during my stay in Sendai.

138

Announcement

Junior Faculty/Post-doctoral Positions
Tohoku University
WPI-AIMR
Effective October 1, 2007, Tohoku University created a new Research Institute, theAdvanced Institute for Materials Research (AIMR), based on an initiative of theJapanese Department of Education (MEXT) for World Premier International ResearchCenter Initiative (WPI) to bring together scientists involved in research on nano-scienceand technology.
In the 21st century, material science, broadly defined as the study of how complex/novel
properties arise in matters/materials from the interactions of individual components, willcomprise of inter-discipline collaboration.
(HTTP://WWW.WPI-AIMR.TOHOKU.AC.JP).
Over the next few years, as many as one hundred new appointments at the levels of
post-doctoral fellows and junior faculty will be available. All innovative researchers arewelcome as active promoters of basic/applied sciences in the fields of physicalmetallurgy, physics, chemistry, precision mechanical engineering and electronic /informational engineering.
We are continuously looking for excellent applicants throughout the year.
Please submit
1) a curriculum vitae,
2) research proposal (<3,000 words),
3) summary of previous research accomplishments (<2,000 words),
4) copies of 5 significant publications, and
5) 2 letters of recommendationby email to yoshi@mail.tains.tohoku.ac.jp,
sakurai@imr.tohoku.ac.jp, andwpi-office@bureau.tohoku.ac.jp.
All files must be submitted electronically in pdf or Word format.
Applications from, or nominations of, women and minority candidates are encouraged.
Tohoku University WPI-AIMR is an affirmative action / equal opportunity employer.

141

Graduate Student scholarship
In Materials Science/Engineering
WPI-AIMR
Graduate Student scholarship
Effective October 1, 2007, Tohoku University created a new Research Institute, theAdvanced Institute for Materials Research (AIMR), based on an initiative of theJapanese Department of Education (MEXT) for World Premier International ResearchCenter Initiative (WPI) to bring together scientists involved in research on nano-scienceand technology.
In the 21st century, material science, broadly defined as the study of how complex/novel
properties arise in matters/materials from the interactions of individual components, will
becomes an essential and most important research topics(HTTP://WWW.WPI-AIMR.TOHOKU.AC.JP).
TU WPI-AIMR is now looking for young motivated Ph.D. graduate student candidates
in the fields of physical metallurgy, physics, chemistry, mechanical engineering andelectronic / informational technology. All innovative M. S. students are welcome asactive promoters of basic/applied sciences in these fields.
Applications are continuously screened throughout the year.
Please submit
1) a curriculum vitae,
2) research proposal (<1,000 words),
3) 2 letters of recommendation,by email toyoshi@mail.tains.tohoku.ac.jp,
sakurai@imr.tohoku.ac.jp, andwpi-office@bureau.tohoku.ac.jp.
All files must be submitted electronically in pdf or Word format.

142

WPI-AIMR
Workshop Guideline
Tohoku University’s new Research Institute, the Advanced Institute for Materials
Research (WPI-AIMR) solicits several applications per year for International
Workshops in the field of “broadly defined Materials Science.”
Guidelines:
1) Organizers
Qualified research staff of academic institutions and public or private researchestablishments can submit the application for an international workshop to be held at
WPI-AIMR or its Satellite branches, jointly with the WPI-AIMR principal
investigator(s) whose research interest overlaps with the scope of the workshop.
2) Financial support
Under normal circumstances, WPI-IMR supports up to 2/3 of the workshop budget,
while the organizer is expected to cover the rest.
3) deadline
The application must be received at least four months in advancetoyoshi@mail.tains.tohoku.ac.jp,
sakurai@imr.tohoku.ac.jp, andwpi-office@bureau.tohoku.ac.jp.
All files must be submitted electronically in pdf or Word format.

143

Appendix

Administrative Office
TEL: +81-22-217-5922 / FAX: +81-22-217-5129

Yoshinori YAMAMOTO

Toshio SAKURAI

Institute Director
yoshi@mail.tains.tohoku.ac.jp

Director of Administrative
Office+81-22-217-5130

sakurai@imr.tohoku.ac.jp+81-22-217-5973

Hiroshi KOMATSU

Nobuo ONO

Specially Appointed Professorand Associate Editor

Deputy Director of
Administrative Office

hiroshi@wpi-aimr.tohoku.ac.jp

nob-ono@bureau.tohoku.ac.jp+81-22-217-5980

General Affairs Section TEL: +81-22-217-5922・5971・5972 / wpi-office@bureau.tohoku.ac.jp

Keiichi HASHIMOTO Asuka SAITO
Chief

Atsuko CHIGIRI

Yoko CHIBA

Nao KONOHARA

Sayaka UNOURA

Kaori SATO

Accounting Section
TEL: +81-22-217-5923
wpi-keiri@wpi-aimr.tohoku.ac.jp
Yasushi WAGATSUMA Tomohiro OKAZAKI Ippei ZENIYA Yuki KOBAYASHI
Chief

Noriko DAIGAKU

Property Management
Section
TEL: +81-22-217-5924
wpi-yodo@wpi-aimr.tohoku.ac.jp
Masahiro YOSHIDA Takashi OHMORI Hajime YOSHIDA
ChiefToshio ONO

Yumi OHTOMOInternational Academic
Affairs Section
TEL: +81-22-217-5922
wpi-kenkyo@wpi-aimr.tohoku.ac.jp
Yasukazu YANAGAWA Etsuko HAGITA

X-1
Ｘ-１

Chie CHIBA

Mariko ONODERA Ayumi OKAMOTODIRECTORY
As of September 12, 2008
Name

Phone Number (+81-22- _____)

E-mail Address

1. ADSCHIRI, Tadafumi (Prof.)

217-5629

ajiri@tagen.tohoku.ac.jp

2. HOJO, Daisuke (Assist. Prof.)

217-5631

dhojo@tagen.tohoku.ac.jp

3. MINAMI, Kimitaka (Assist. Prof.)

217-5631

nankim@tagen.tohoku.ac.jp

4. RANI, Varu (Research Assist.)

217-5630

chauhan@mail.tagen.tohoku.ac.jp

5. YOO, Jungwoo (Research Assist.)

217-5630

jw-yoo@mail.tagen.tohoku.ac.jp

6. CHEN, Mingwei (Prof.)

215-2143

mwchen@imr.tohoku.ac.jp

7. FUJITA, Takeshi (Assist. Prof.)

215-2139

tfujita@imr.tohoku.ac.jp

8. CHEN, Luyang (Research Assoc.)

215-2138

chenly@imr.tohoku.ac.jp

9. GUAN, Pengfei (Research Assoc.)

215-2138

pf.guan@imr.tohoku.ac.jp

10. ZHANG, Xuefeng (Research Assoc.)

215-2138

xfzhang@imr.tohoku.ac.jp

11. ESASHI, Masayoshi (Prof.)

795-6934

esashi@mems.mech.tohoku.ac.jp

12. AKIYAMA, Kotone (Assist. Prof.)

795-6258

akiyama@mems.mech.tohoku.ac.jp

13. MUROYAMA, Masanori (Assist. Prof.)

795-6256

muroyama@mems.mech.tohoku.ac.jp

14. YOSIHIDA, Shinya (Research Assoc.)795-6468s-yoshida@mems.mech.tohoku.ac.jp<Adschiri Group><Chen Group><Esashi Group><Gessner Group>
15. GESSNER, Thomas (Prof.)+49- 371- 531-24060

Thomas.Gessner@zfm.tu-chemnitz.de

16. LIN, Yu-Ching (Assist. Prof.)+49- 371- 531-37164

yuching.lin@enas.fraunhofer.de<Greer Group>
17. GREER, Alan Lindsay (Prof.)+44-1223-334308

18. MADGE, Shantanu (Research Assoc.)

215-2113

alg13@cam.ac.uk
S.Madge.99@cantab.net<Hashizume Group>

tomihiro.hashizume.qb@hitachi.com

19. HASHIZUME, Tomihiro (Prof.)+81-49-296-6111

20. HITOSUGI, Taro (Assoc. Prof.)

217-5944

hitosugi@wpi-aimr.tohoku.ac.jp

21. FUKUI, Nobuyuki (Research Assoc.)

217-5948

n-fukui@wpi-aimr.tohoku.ac.jp

22. SHIMIZU, Ryota (Research Assist.)

217-5948

shimizu@chem.s.u-tokyo.ac.jp

X-2

< Hemker Group>
23. HEMKER, Kevin J. (Prof.)+1- 410- 516-4489

hemker@jhu.edu<Ikuhara Group>
24. IKUHARA, Yuichi (Prof.)+81-3-5841-7688

ikuhara@sigma.t.u-tokyo.ac.jp

25. TSUKIMOTO, Susumu (Lecturer)

217-5934

tsukimoto@wpi-aimr.tohoku.ac.jp

26. SAITO, Mitsuhiro (Assist. Prof.)

217-5933

saito@wpi-aimr.tohoku.ac.jp

27. WANG, Zhongchang (Research Assoc.)

217-5933

zcwang@wpi-aimr.tohoku.ac.jp

28. INOUE, Akihisa (Prof.)

217-4800

ainoue@imr.tohoku.ac.jp

29. LOUZGUINE, Dmitri (Prof.)

215-2592

dml@imr.tohoku.ac.jp

30. NAKAYAMA, Koji S. (Assoc. Prof.)

215-2023

kojisn@imr.tohoku.ac.jp

31. TAKEUCHI, Akira (Assoc. Prof.)

215-2112

takeuchi@imr.tohoku.ac.jp

32. QIN, Chunling (Assist. Prof.)

215-3048

clqin@imr.tohoku.ac.jp

33. ITAYA, Kingo (Prof.)

795-5868

itaya@atom.che.tohoku.ac.jp

34. IKEDA, Susumu (Assist. Prof.)

795-5869

ikeda@atom.che.tohoku.ac.jp

35. KUZUME, Akiyoshi (Assist. Prof.)

795-5869

kuzume@atom.che.tohoku.ac.jp

36. KAWASAKI, Masashi (Prof.)

215-2085

kawasaki@imr.tohoku.ac.jp

37. MAKINO, Takayuki (Lecturer)

217-5600

tmakino@imr.tohoku.ac.jp

38. UENO, Kazunori (Assist. Prof.)

215-2088

uenok@imr.tohoku.ac.jp

39. HIRAGA, Hiroki (Research Assoc.)

217-5600

hiraga.hiroki@imr.tohoku.ac.jp<Inoue Group><Itaya Group><Kawasaki Group><Lagally Group>
40. LAGALLY, Max G. (Prof.)+1-608-263-2078

lagally@engr.wisc.edu<Miyazaki Group>
41. MIYAZAKI, Terunobu (Prof.)

217-6000

miyazaki@wpi-aimr.tohoku.ac.jp

42. MIZUKAMI, Shigemi (Assist. Prof.)

217-6003

mizukami@wpi-aimr.tohoku.ac.jp

43. WATANABE, Daisuke (Research Assoc.)

217-6003

watanabe@wpi-aimr.tohoku.ac.jp

44. WU, Feng (Research Assoc.)

217-6004

fengwu@wpi-aimr.tohoku.ac.jp

X-3

Name

Phone Number (+81-22- _____)

E-mail Address

217-5522

nakazawa@riec.tohoku.ac.jp

46. NISHI, Toshio (Prof.)

217-5926

nishi.toshio@wpi-aimr.tohoku.ac.jp

47. NAKAJIMA, Ken (Assoc. Prof.)

217-5927

knakaji@wpi-aimr.tohoku.ac.jp

48. FUJINAMI, So (Research Assoc.)

217-5928

fujinami@wpi-aimr.tohoku.ac.jp

49. WANG, Dong (Research Assoc.)

217-5928

wangdthu@wpi-aimr.tohoku.ac.jp795-3952

ohmi@fff.niche.tohoku.ac.jp+1-413-545-2680

russell@mail.pse.umass.edu<Nakazawa Group>
45. NAKAZAWA, Masataka (Prof.)<Nishi Group><Ohmi Group>
50. OHMI, Tadahiro (Prof.)<Russell Group>
51. RUSSELL, Thomas P. (Prof.)<Shimomura Group>
52. SHIMOMURA, Masatsugu (Prof.)

217-5329

shimo@tagen.tohoku.ac.jp

53. ISHII, Daisuke (Assist. Prof.)

217-5824

dishii@tagen.tohoku.ac.jp<Shluger Group>a.shluger@ucl.ac.uk

54. SHLUGER, Alexander (Prof.)

217-5942 / +44-171-391-1312

55. SUSHKO, Peter (Assoc. Prof.)

217-5942

p.sushko@wpi-aimr.tohoku.ac.jp

56. TAKAHASHI, Takashi (Prof.)

795-6417

t.takahashi@arpes.phys.tohoku.ac.jp

57. RICHARD, Pierre (Assist. Prof.)

795-6477

p.richard@arpes.phys.tohoku.ac.jp

58. SOUMA, Seigo (Assist. Prof.)

795-6477

s.souma@arpes.phys.tohoku.ac.jp

59. TANIGAKI, Katsumi (Prof.)

795-6469

tanigaki@sspns.phys.tohoku.ac.jp

60. JU, Jing (Assist. Prof.)

795-6468

jujing@sspns.phys.tohoku.ac.jp

61. NOUCHI, Ryo (Assist. Prof.)

795-6468

nouchi@sspns.phys.tohoku.ac.jp

62. LI, Zhaofei (Research Assoc.)795-6468

zfli@sspns.phys.tohoku.ac.jp<Takahashi Group><Tanigaki Group>

X-4

<Tokuyama Group>
63. TOKUYAMA, Michio (Prof.)

217-5327

tokuyama@fmail.ifs.tohoku.ac.jp

64. SIMDYANKIN, Sergey (Assist. Professor)

217-5282

simdyankin@athena22.ifs.tohoku.ac.jp

65. NARUMI, Takayuki (Research Assist.)

217-5282

narumi@athena22.ifs.tohoku.ac.jp<Tromp Group>
66. TROMP, Rudolf M. (Prof.)+1-914-945-1242

67. AL-MAHBOOB, Abdullah (Assist. Prof.)

215-2023

rtromp@us.ibm.com
almahb-0@imr.tohoku.ac.jp<Tsukada Group>
68. TSUKADA, Masaru (Prof.)

217-5937 / +81-3-5286-8323

69. AKAGI, Kazuto (Assoc. Prof.)

217-5940

70. TAMURA, Hiroyuki (Research Assoc.)

217-5938

71. MASAGO, Akira (Research Assoc.)

217-5939

72. ARAIDAI, Masaaki (Visiting Research Assoc.)

tsukada@wpi-aimr.tohoku.ac.jp
akagi@wpi-aimr.tohoku.ac.jp
masago@wpi-aimr.tohoku.ac.jp

217-5939<Wan Group>
73. WAN, Li-Jun (Prof.)+86-62558934

74. WEN, Rui (Research Assoc.)

795-5869

wanlijun@iccas.ac.cn
ruiwen@atom.che.tohoku.ac.jp<Weiss Group>
75. WEISS, Paul S. (Prof.)+1-814-865-3693

stm@psu.edu+86-10-62795618

qkxue@mail.tsinghua.edu.cn<Xue Group>
76. XUE, Qi-Kun (Prof.)

217-5948

liu@wpi-aimr.tohoku.ac.jp215-2035

kyamada@imr.tohoku.ac.jp

79. HORIGANE, Kazumasa (Research Assoc.) 215-2039

khorigane@imr.tohoku.ac.jp

80. IIKUBO, Satoshi (Research Assoc.)

215-2039

iikubo.satoshi@imr.tohoku.ac.jp

81. TOMIYASU, Keisuke (Research Assoc.)

215-2038

tomiyasu@imr.tohoku.ac.jp795-6812

yama@mail.pharm.tohoku.ac.jp

77. LIU, Hongwen (Assist. Prof.)<Yamada Group>
78. YAMADA, Kazuyoshi (Prof.)<Yamaguchi Group>
82. YAMAGUCHI, Masahiko (Prof.)<Yavari Group>
83. YAVARI, Alain Reza (Prof.)+ 33-(0) 4 76 82 65 16

yavari@ltpcm.inpg.fr
georgara@minatec.inpg.fr

84. GEOGARAKIS, Konstantinos (Research Assoc.)

X-5

Volume 3

WPI-AIMR NEWSN

September 12, 2008

AOMORIMORIOKAAKITAWorld Premier International Research Center
Advanced Institute for Materials Research

SENDAIYAMAGATASENDAI AIRPORT

Tohoku University

FUKUSHIMA

MITO
OARAI

Cover: Nano Materials with Regulated Endohedral Spaces by K. Tanigaki, Professor of WPI-AIMR
Thanks to the development of micro/nano-fabrication technologies, it is now possible to form various structures inTOKYOthe microscopic area, and even, when using atom manipulation technologies such as STM or AFM, to form much

NARITAAIRPORTsmaller patterns by moving atoms one after another. However, in the physical microfabrication process, emerging
SHINKANSEN(JR)

defects may become a large obstruction upon observation of solid-state properties expected in the nano region.
Moving atoms one-by-one to form a structure large enough to observe its solid-state properties requires a long

OSAKA

period. Various nano space materials formed in the nanometer range through application of self-organization
phenomenon are expected to constitute a new paradigm of material science that can provide possibilities for new
solid-state researches as well as various applications.

表紙：種々のナノ空間を有する物質群 （WPI-AIMR

谷垣勝己教授提供）

微細加工技術の進展により、現在では多様な微細領域の構造体が構築できるようになっている。また、STM や AFMなどの原子操作技術を用いれば、原子を１個ずつ動かして微細なパターンを形成することも可能である。しかし、物理的な微細加工では発生する欠陥がナノ領域で発現する物性を観測する際に大きな障害となり生じる。また、原子を１つ１つ移動させて物性を観測するために十分な大きさを有する構造体を構築するためには、膨大な時間が必要となる。自己組織化現象を適用することにより、ナノメートル領域に形成される種々のナノ空間物質は、多様な構造とともに新しい物性研究の可能性を与える物質科学のニューパラダイムとなる事が期待される。

KANSAIAIRPORT

World Premier International Research Center
Advanced Institute for Materials Research

Tohoku University

2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Phone : +81-22-217-5922
FAX : +81-22-217-5129
E-mail : wpi-oﬃce@bureau.tohoku.ac.jp
URL : http : //www.wpi-aimr.tohoku.ac.jp

Volume 3

WPI-ADVANCED INSTITUTE FOR MATERIALS RESEARCH NEWS
September 12, 2008

2-1-1 katahira, Aoba-ku, Sendai 980-8577
Japan
Phone: +81-22-217-5922
FAX: +81-22-217-5129

September 12, 2008

Volume 3

World Premier International Research Center
Advanced Institute for Materials Research
Tohoku University

WPI-AIMR NEWSWorld Premier International Research Center
Advanced Institute for Materials Research
Tohoku University