Printed with permission of The Institute of Pure and Applied Physics (IPAP)

JAPANESE JOURNAL OF APPLIED PHYSICS [Part2]

Abstracts of Express Letters
Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L457-L459
Part 2, No. 17, 25 May 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L486-L489
Part 2, No. 19, 25 May 2006
©2006 The Japan Society of Applied Physics

Room-Temperature Epitaxial Growth of GaN
on Atomically Flat MgAl2O4 Substrates byPulsed-Laser Deposition

Stress Characterization of Si by a Scanning
Near-Field Optical Raman Microscope with
Spatial Resolution and with Penetration
Depth at the Nanometer Level,using Resonant Raman Scattering

Guoqiang Li1, Jitsuo Ohta1,2, Koichiro Okamoto1, Atsushi Kobayashi1and Hiroshi Fujioka1,2,*(Received March 30, 2006; accepted April 5, 2006; published online April 21, 2006)

We have grown GaN films on MgAl2O4(111) substrates at room
temperature (RT) and investigated the structural properties of the films.
The atomically flat surfaces of MgAl2O4 with a step and terrace structure are obtained by annealing at 1000ºC in a box made of ceramic
MgAl 2O 4. It is found that GaN(0001) grows epitaxially on atomically flat MgAl2O 4(111) surfaces even at RT. The epitaxial relationship between the GaN epilayer and the MgAl2O4 substrate is GaN[11\bar20]//MgAl2O4[0\bar11]. GaN films have a clear six fold symmetry
without 30º rotational domains. The interfacial reaction between GaN
and MgAl2O4 is completely suppressed in the case of RT growth.
[DOI : 10.1143/JJAP.45.L457]
Keywords: MgAl2O4, GaN, atomically flat surface, pulsed laser
deposition
1 Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo
153-8505, Japan
2 Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu-ku,
Kawasaki 213-0012, Japan* E-mail address: hfujioka@iis.u-tokyo.ac.jp

Masanobu Yoshikawa, Masataka Murakami, Keiko Matsuda, Ryuichi
Sugie, Hideyuki Ishida and Ryosuke Shimizu1(Received April 11, 2006; accepted April 20, 2006; published online May 12, 2006)

We have developed a new tapping mode-scanning near-field optical
Raman microscope (SNORM) with a caved and pyramidical probe, using
resonant Raman scattering and measured the stress distribution ofvery-large-scale integration (VLSI) standards made of the silicon dioxide
film and Si. It has been found that compressive stresses of about 0.69
GPa/cm2 are concentrated on the corner of the area uncovered by silicon
dioxide. The SNORM we developed has at least the spatial resolution ofless than 250nm and is a useful tool to measure image of stresses in Si
devices within a short time and with a penetration depth of 5nm.
[DOI : 10.1143/JJAP.45.L486]
Keywords: near-field, Raman, resonant Raman, stress, silicon
Toray Research Center Inc., 3-3-7 Sonoyama, Otsu, Shiga 520-8567, Japan
1 PHOTON Design Corporation, 2-24-6 Kamiya, Kita-ku, Tokyo 115-0043, Japan

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L460-L462
Part 2, No. 17, 25 May 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L513-L515
Part 2, No. 20, 25 June 2006
©2006 The Japan Society of Applied Physics

Atmospheric Pressure Fluorocarbon-Particle
Plasma Chemical Vapor Deposition for
Hydrophobic Film Coating

Optical Stark Effect of Exciton in
Semiconducting Single-Walled Carbon
Nanotubes

Mikio Nagai, Osamu Takai1 and Masaru Hori*

Shinji Matsumoto, Hiroyuki Matsui, Atsushi Maeda, Taishi Takenobu1,2,
Yoshihiro Iwasa1,2, Yasumitsu Miyata3,4, Hiromichi Kataura4, Yutaka
Maniwa2,3 and Hiroshi Okamoto*(Received March 24, 2006; accepted April 4, 2006; published online April 21, 2006)

We have realized a fluorocarbon-particle plasma chemical vapor
deposition employing an atmospheric pressure plasma with continuouswave microwave excitation. Spherical fluorocarbon particles 50 – 100nm
in diameter were formed in the atmospheric pressure plasma. The gas
temperature in the plasma was controlled to be 480 K, as estimatedusing numerical calculations from N2 emission spectra. It was foundthat the gas temperature was an important factor for the synthesis of
the fluorocarbon particles. The particles were negatively charged downstream from the plasma and were transported efficiently to the substrateby an electric field. A hydrophobic coating with a contact angle of 140º
was achieved at room temperature. [DOI : 10.1143/JJAP.45.L460]
Keywords: hydrophobic, atmospheric, plasma, gas temperature,
fluorocarbon
Department of Electrical Engineering and Computer Science, Graduate School of Engineering,
Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
1 EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603,
Japan* E-mail address: hori@nuee.nagoya-u.ac.jp

16

JSAP International No.15 (January 2007)(Received April 18, 2006; accepted April 28, 2006; published online May 19, 2006)

An instantaneous blue shift of exciton absorption due to the optical
Stark effect was observed in isolated semiconducting single-walledcarbon nanotubes (SWNTs) by using a femtosecond (fs) pump-probe
spectroscopy. From the analysis of time profiles of transient absorptionchanges, the photoinduced shift and the dipole moment of the exciton
transition were evaluated as ~1.1meV for the pump fluence of 34µJ/cm2
and ~6eÅ, respectively. Such a large dipole moment as well as ultrafast
recovery of real carrier excitations suggests high potential of SWNTs foran ultrafast optical-switching material. [DOI : 10.1143/JJAP.45.L513]
Keywords: carbon nanotube, optical Stark effect, nonlinear opticalresponse, femtosecond spectroscopy, exciton
Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561,
Japan
1 Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
2 CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 322-0012, Japan
3 Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
4 Nanotechnology Research Institute, National Institute of Advanced Industrial Science andTechnology (AIST), Tsukuba, Ibaraki 305-8562, Japan* E-mail address: okamotoh@k.u-tokyo.ac.jp

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L549-L551
Part 2, No. 22, 25 June 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L611-L613
Part 2, No. 24, 25 July 2006
©2006 The Japan Society of Applied Physics

Misfit Dislocation Generation in InGaN
Epilayers on Free-Standing GaN

Characteristics of InGaN with High In
Concentrations Grown on ZnO at
Low Temperatures

Rong Liu, Jin Mei, Sridhar Srinivasan, Hiromasa Omiya, Fernando
A. Ponce*, David Cherns1, Yukio Narukawa2 and Takashi Mukai2Atsushi Kobayashi1, Jitsuo Ohta1,2 and Hiroshi Fujioka1,2,*(Received May 6, 2006; accepted May 18, 2006; published online June 2, 2006)(Received May 7, 2006; accepted May 28, 2006; published online June 16, 2006)

We have found that, in the absence of threading dislocations in
InxGa1-xN/GaN heterostructures, coherent generation of misfit dislocations occurs for x > 0.11in ~100-nm-thick epilayers. We focus thisreport on In0.17Ga0.83N grown on a low-defect-density GaN free-standing
substrate (with 1.9% lattice mismatch). A diffraction contrast analysis
carried out in the transmission electron microscope showed straightline defects with Burgers vectors 2/3 <11-20> (i.e., 2a, where a is thehexagonal plane lattice parameter), which extended many micrometers
approximately along <1-100> directions and with an average lateralspacing of 90 nm. Although these defects were complex and mostly
sessile, evidence was found that they can dissociate into glissile misfit
dislocations with Burgers vectors of 1/3 <11-20>. It is proposed thatthe defects are generated by a punch-out mechanism involving slip on
inclined prismatic planes. The properties of these defects and their role inrelieving misfit strains are discussed. [DOI : 10.1143/JJAP.45.L549]
Keywords: misfit dislocations, InGaN epilayers, epitaxy on bulk
GaN, plastic relaxation, punch-out relaxation process

We have investigated the effect of substrate temperature on the
structural properties of InGaN with high In concentrations grown on
atomically flat ZnO substrates by pulsed laser deposition using an
In0.65Ga0.35 alloy target. Although the InGaN film grown at 650ºC shows
poor crystalline quality and has a rough surface, those grown at temperatures below 420ºC have surfaces with stepped and terraced structures. We found that the epitaxial growth of InGaN at low temperatures
proceeds by the layer-by-layer mode, which is consistent with the atomically flat surfaces of InGaN. We also found that phase separation of
InGaN is suppressed by reducing the growth temperature.
[DOI : 10.1143/JJAP.45.L611]
Keywords: InGaN, ZnO, pulsed laser deposition, low temperature
growth, phase separation
1 Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo
153-8505, Japan
2 Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu-ku,
Kawasaki 213-0012, Japan* E-mail address: hfujioka@iis.u-tokyo.ac.jp

Department of Physics and Astronomy, Arizona State University, Tempe, Arizona, U.S.A.
1 H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, U.K.
2 Nichia Corporation, 491 Oka, Kaminaka, Anan, Tokushima 774-8601, Japan* E-mail address: ponce@asu.edu

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L552-L554
Part 2, No. 22, 25 June 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L638-L640
Part 2, No. 25, 25 July 2006
©2006 The Japan Society of Applied Physics

Effect of a Generalized Particle Momentum
Distribution on Plasma Nuclear Fusion Rates

Dye-Sensitized Solar Cells with Conversion
Efficiency of 11.1%

Yeong E. Kim* and Alexander L. Zubarev**

Yasuo Chiba, Ashraful Islam, Yuki Watanabe, Ryoichi Komiya, Naoki
Koide and Liyuan Han*

(Received December 19, 2005; accepted May 13, 2006; published online June 2, 2006)

We investigate the effect of a generalized particle momentum distribution derived by Galitskii and Yakimets (GY) on nuclear reaction rates
in plasma. We derive an approximate semi-analytical formula for nuclear
fusion reaction rate between nuclei in a plasma (quantum plasma nuclear
fusion; or QPNF). The QPNF formula is applied to calculate deuteron –deuteron fusion rate in a plasma, and the results are compared with theresults calculated with the conventional Maxwell – Bolzmann velocity
distribution. As an application, we investigate the deuteron – deuteron
fusion rate for mobile deuterons in a deuterated metal/alloy. The calculated deuteron – deuteron fusion rates at low energies are enormously
enhanced due to the modified tail of the GY’s generalized momentum
distribution. Our preliminary estimates indicate also that the deuteron –lithium (D+Li) fusion rate and the proton – lithium (p+Li) fusion rate in a
metal/alloy at ambient temperatures are also substantially enhanced.
[DOI : 10.1143/JJAP.45.L552]
Keywords: generalized particle momentum distribution, quantum
plasma nuclear fusion(Received June 7, 2006; accepted June 9, 2006; published online June 23, 2006)

Dye-sensitized solar cells (DSCs) using titanium dioxide ( TiO2) electrodes with different haze were investigated. It was found that the incident photon to current efficiency ( IPCE ) of DSCs increases with increasein the haze of the TiO2 electrodes, especially in the near infrared wavelength region. Conversion efficiency of 11.1%, measured by a public test
center, was achieved using high haze TiO2 electrodes. This indicates thatraising the haze of TiO2 electrodes is an effective technique for improvement of conversion efficiency. [DOI : 10.1143/JJAP.45.L638]
Keywords: dye-sensitized solar cells, haze, internal resistance, TiO2electrode, IPCE
Solar Systems Development Center, Sharp Corporation, 282-1 Hajikami, Katsuragi, Nara
639-2198, Japan* E-mail address: han.liyuan@sharp.co.jp

Purdue Nuclear and Many-Body Theory Group, Department of Physics, Purdue University, West
Lafayette, IN 47907, U.S.A.
* E-mail address: yekim@physics.purdue.edu** E-mail address: zubareva@physics.purdue.edu

JSAP International No.15 (January 2007)17

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L659-L662
Part 2, No. 26, 25 July 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L679-L682
Part 2, No. 27, 25 July 2006
©2006 The Japan Society of Applied Physics

Blue, Green, and Amber InGaN/GaN
Light-Emitting Diodes on Semipolar {11-22}
GaN Bulk Substrates

Electro-Luminescence from Ultra-Thin Silicon

Mitsuru Funato*, Masaya Ueda, Yoichi Kawakami, Yukio Narukawa1,
Takao Kosugi1, Masayoshi Takahashi1 and Takashi Mukai1(Received June 10, 2006; accepted June 17, 2006; published online June 30, 2006)

We demonstrate the fabrication of blue, green, and amber
InGaN/GaN light-emitting diodes (LEDs) on semipolar {11-22} bulk GaN
substrates. The {11-22}GaN substrates used in this study are produced by
cutting out from a c-oriented GaN bulk crystal grown by hydride vapor
epitaxy. The LEDs have a dimension of 320 × 320µm2 and are packed
in an epoxide resin. The output power and external quantum efficiency(EQE) at a driving current of 20mA are 1.76mW and 3.0%, respectively,
for the blue LED, 1.91mW and 4.1% for the green LED, and 0.54mW
and 1.3% for the amber LED. The maximum output powers obtainedwith a maximum current of 200 mA are 19.0 mW (blue), 13.4 mW(green), and 1.9 mW (amber), while the maximum EQEs are 4.0% at
140mA (blue), 4.9% at 0.2mA (green), and 1.6% at 1mA (amber). It is
confirmed that the emission light is polarized along the [1-100] direction,reflecting the low crystal symmetry of the {11-22} plane.
[DOI : 10.1143/JJAP.45.L659]
Keywords: {11-22} plane, semipolar, GaN bulk substrate, InGaN/GaN
quantum well, light-emitting diode, polarized light

Shin-ichi Saito*, Digh Hisamoto, Haruka Shimizu, Hirotaka Hamamura,
Ryuta Tsuchiya, Yuichi Matsui, Toshiyuki Mine, Tadashi Arai, Nobuyuki
Sugii, Kazuyoshi Torii, Shin’ichiro Kimura and Takahiro Onai

(Received May 31, 2006; accepted June 19, 2006; published online July 7, 2006)

Ultra-thin single crystal silicon with the (100) surface formed by
the local-oxidation-of-silicon (LOCOS) on a silicon-on-insulator (SOI)
substrate becomes a quasi-direct band-gap semiconductor due to thequantum mechanical confinement effect. The device is a simple pn diodein a planar structure. Electro-luminescence (EL) has been observed by thelateral carrier injections into the two-dimensional quantum well.
[DOI : 10.1143/JJAP.45.L679]
Keywords: quantum mechanical confinement, silicon, photoluminescence, electroluminescence, diode, quantum wellCentral Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo 185-8601, Japan* E-mail address: ssaito@crl.hitachi.co.jp

Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510, Japan
1 Nitride Semiconductor Research Laboratory, Nichia Corporation, Tokushima 774-8601,
Japan* E-mail address: funato@kuee.kyoto-u.ac.jp

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L663-L665
Part 2, No. 26, 25 July 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L683-L685
Part 2, No. 27, 25 July 2006
©2006 The Japan Society of Applied Physics

Investigation of Spin Voltaic Effect in a p – nHeterojunction

Current-Excited Magnetization Dynamics in
Narrow Ferromagnetic Wires

Tsuyoshi Kondo*, Jun-ji Hayafuji and Hiro Munekata

Yoshihiko Togawa1,*, Takashi Kimura1,2, Ken Harada1,3, Tetsuya Akashi3,4,
Tsuyoshi Matsuda1,3, Akira Tonomura1,3 and Yoshichika Otani1,2(Received May 25, 2006; accepted June 17, 2006; published online June 30, 2006)

Model calculation and experimental data of circularly-polarizedlight-dependent photocurrent in a n-GaAlAs / p-GaInAs / p-GaAs heterostructure are reported. It is found that, with appropriate heterojunction
parameters, spin voltaic effect may survive across the heterojunction
and give rise to detectable polarization-dependent photocurrent signals
which are greater than those due to the magnetic-circular-dichroism
background. [DOI : 10.1143/JJAP.45.L663]
Keywords: III – V semiconductors, heterostructure, spintronics,
g-factor, spin voltaic effect, photodiode
Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, 4259-G2-13
Nagatsuta, Midori-ku, Yokohama 226-8502, Japan* E-mail address: tkondo@isl.titech.ac.jp(Received June 2, 2006; accepted June 20, 2006; published online July 7, 2006)

We investigate the current-excited magnetization dynamics in anarrow ferromagnetic Permalloy wire by means of Lorentz microscopy,
together with the results of simultaneous transport measurements. A
detailed structural evolution of the magnetization is presented as a function of the applied current density. Local structural deformation, bidirectional displacement, and magnetization reversal are found below theCurie temperature with increasing the current density. We discuss probable mechanisms of observed features of the current-excited magnetization dynamics. [DOI : 10.1143/JJAP.45.L683]
Keywords: current-driven magnetization dynamics, magnetic
domain wall, spin torque, Permalloy wire, Lorentz
microscopy, electron holography
1 Frontier Research System, The Institute of Physical and Chemical Research (RIKEN),
Hirosawa, Wako, Saitama 351-0198, Japan
2 Institute for Solid State Physics, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba
277-8581, Japan
3 Advanced Research Laboratory, Hitachi, Ltd., Akanuma, Hatoyama, Saitama 350-0395,
Japan
4 Hitachi Instruments Service Co., Ltd., Yotsuya, Shinjuku-ku, Tokyo 160-0004, Japan* All correspondence should be addressed to ytogawa@harl.hitachi.co.jp

18

JSAP International No.15 (January 2007)

Abstracts of Express Letters

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L686-L689
Part 2, No. 27, 25 July 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L720-L722
Part 2, No. 28, 25 July 2006
©2006 The Japan Society of Applied Physics

Investigation of Current on the Conducting
Target Biased with a Large Negative Potential
in the Non-Uniform Plasma

Growth of Super Long Aligned Brush-Like
Carbon Nanotubes

1

Jae-Myung Choe, Kyoung-Jae Chung, Hui-Dong Hwang , Yong-Seok
Hwang, Kwang-Cheol Ko1 and Gon-Ho Kim*

(Received June 13, 2006; accepted June 19, 2006; published online July 7, 2006)

It was investigated the current on a biased target in the non-uniform
plasma. The argon plasma was generated at the low pressure of
0.5 – 5 mTorr and the stainless steel target was biased with 0.2 – 6 KV
negatively. The target current increases with increasing the target
voltage due to the non-uniform plasma distributed near the target,
which follows the Child law. The secondary emission current, following
the square root of target voltage, is superposed to the ion current. For
the higher pressures of larger than 1.5mTorr, the target current is larger
than the expected current of Bohm current plus the secondary emission current. The deviation increases drastically with increasing the operating pressure, which may due to the local ionization near the target.
This phenomenon is important to understand more accurately the highvoltage sheath formation in practices. [DOI : 10.1143/JJAP.45.L686]
Keywords: target current, negative bias, sheath, non-uniform
plasma, secondary electron emission

Supriya Chakrabarti, Takeshi Nagasaka1, Yuya Yoshikawa2, Lujun Pan2
and Yoshikazu Nakayama2(Received June 25, 2006; accepted June 28, 2006; published online July 14, 2006)

Efficient chemical vapor deposition (CVD) synthesis of super long(7mm) aligned carbon nanotubes (CNTs) with high-density is reported
here. Activity of catalyst nanoparticles has been achieved for very longtime periods (ca. 12h) by optimization of experimental parameters. The
relative levels of ethylene and water, as well as those of ethylene and H2,
were found to be most important for achieving extended-time activityof the catalyst. Transmission electron microscope (TEM) images revealed
that the nanotubes were mainly double-walled, but very few singlewalled and multi-walled nanotubes were also present in the sample.
[DOI : 10.1143/JJAP.45.L720]
Keywords: carbon nanotube, super long, vertically aligned, thermal
chemical vapor deposition, double-walled nanotubes
Osaka Science and Technology Center, Innovation Plaza Osaka, 3-1-10 Techno Stage, Izumi,
Osaka 594-1144, Japan
1 Taiyo Nippon Sanso Corp., Toyo Bldg., 1-3-26 Koyama, Shinagawa-ku, Tokyo 142-8558,
Japan
2 Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture
University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan

Department of Nuclear Engineering, Seoul National University, Seoul 151-744, Korea
1 Department of Electrical Engineering, Hanyang University, Seoul 133-791, Korea* Corresponding author. E-mail address: ghkim@snu.ac.kr

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L717-L719
Part 2, No. 28, 25 July 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L749-L751
Part 2, No. 29, 25 August 2006
©2006 The Japan Society of Applied Physics

Spin-Dependent Transport in C60 – Co
Nano-Composites

First-Order AlInGaN 405nm Distributed
Feedback Laser Diodes by Current Injection

Shinji Miwa, Masashi Shiraishi*, Masaki Mizuguchi, Teruya Shinjo andYoshishige Suzuki

Shingo Masui, Kazutaka Tsukayama, Tomoya Yanamoto, Tokuya Kozaki,
Shin-ichi Nagahama and Takashi Mukai(Received June 13, 2006; accepted June 30, 2006; published online July 14, 2006)(Received June 27, 2006; accepted July 4, 2006; published online July 21, 2006)

C60 – Co nano-composites, in which Co nano-particles are embedded
in C60 molecules, have been fabricated and a magnetoresistance (MR)ratio of 8% has been observed at T = 4.2 K. In addition, we havesucceeded in observing a clear MR curve even at room temperature (RT).
The MR effect is ascribed to magnetization of the Co nano-particles andspin-dependent transport in C60 molecules. This study directly indicatesthat RT operation of molecular spin devices can be realized.
[DOI : 10.1143/JJAP.45.L717]
Keywords: magnetoresistance, spin-dependent transport, fullerene,molecular spintronics

The first-oreder AlInGaN 405nm distributed feed-back (DFB) laser
diodes were grown on the c -face sapphire substrates by a metalorganic chemical vapor deposition method. The diffractive grating, which
was shaped by 108nm deep grating of an 85.7nm period with a sidewall angle 89º, was formed into a p-type waveguiding layer. As a result,
we succeeded in demonstrating the first-order AlInGaN based 405nm
DFB laser diodes by pulsed current injection. The threshold current andthe peak lasing wavelength of the DFB laser diode were 190 mA and403.7 nm under pulsed current operation at 25ºC, respectively. The
lasing spectrum was kept the single longitudinal mode emission up to an
output power of 30mW. [DOI : 10.1143/JJAP.45.L749]
Keywords: AlInGaN, laser diode, fist-order, 80nm, DFB, 405nm, EB

Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka,
Osaka 560-8531, Japan* E-mail address: shiraishi@mp.es.osaka-u.ac.jp

LD Development Department, Nichia Corporation, 491 Oka, Kaminaka, Anan, Tokushima774-8601, Japan

JSAP International No.15 (January 2007)19

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L752-L754
Part 2, No. 29, 25 August 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L843-L845
Part 2, No. 32, 25 August 2006
©2006 The Japan Society of Applied Physics

Electron Emission Tip at Extremely Low Bias
Voltage

High-Performance Short-Gate InAlN/GaN
Heterostructure Field-Effect Transistors

Faridur Rahman and Seigi Mizuno

Masataka Higashiwaki1,*, Takashi Mimura1,2 and Toshiaki Matsui1(Received June 27, 2006; accepted July 6, 2006; published online July 21, 2006)(Received July 20, 2006; accepted July 30, 2006; published online August 11, 2006)

We report the invention of a modification technique of tungsten
tip, which results modified tip apex capable of emitting electrons atextremely low bias voltage. Field-ion microscope induces the structuralswitching of the oxidized apex at room temperature, which is frozen out
at low temperature. Thus modified tips exhibit an extraordinary decrease
in applied bias needed for electron emission (typically from -300 to -3.8V).
Electron emission shows good angular confinement with an opening
angle of less than 2º. Such special tip is repeatedly reproducible andstable for several hours at low temperature. [DOI : 10.1143/JJAP.45.L752]
Keywords: field emission (FE), tungsten tip, field ion microscopy(FIM)

We fabricated 60-nm-gate InAlN/GaN heterostructure fieldeffect transistors (HFETs), which had a 6-nm-thick InAlN barrier withan Al composition of 0.86. The devices had a maximum drain current
density of 1.34 A/mm and a maximum extrinsic transconductance of
389 mS/mm. The small-signal performance of the devices showed acurrent-gain cutoff frequency of 172 GHz and a maximum oscillation
frequency of 206 GHz. These DC and RF device characteristics weresuperior to the best values reported for AlGaN (8nm)/GaN HFETs withthe same gate length. [DOI : 10.1143/JJAP.45.L843]
Keywords: InAlN, GaN, heterostructure field-effect transistor(HFET), catalytic chemical vapor deposition (Cat-CVD),
current-gain cutoff frequency (fT), maximum oscillation
frequency (fmax)

Department of Molecular and Material Sciences, Kyushu University, Kasuga, Fukuoka
816-8580, Japan

1 National Institute of Information and Communications Technology, 4-2-1 Nukui-Kitamachi,
Koganei, Tokyo 184-8795, Japan
2 Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0197, Japan* E-mail address: mhigashi@nict.go.jp

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L777-L779
Part 2, No. 30, 25 August 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L846-L848
Part 2, No. 32, 25 August 2006
©2006 The Japan Society of Applied Physics

In Situ Scanning Tunneling Microscope
Observation of InAs Wetting Layer Formation
on GaAs(001) during Molecular Beam Epitaxy
Growth at 500ºC

Continuous-Wave Diode-Pumped Yb:YAG
Laser with High Beam Quality

Tsuyoshi Honma1,2,*, Shiro Tsukamoto1,** and Yasuhiko Arakawa1

We have developed a continuous-wave diode-pumped Yb:YAG laser
with high beam quality applying only a highly doped Yb:YAG crystal thatis pumped directly into the upper lasing level. The laser produces a practically diffraction-limited Gaussian beam, whose M2 factor is 1.36.
[DOI : 10.1143/JJAP.45.L846]
Keywords: Yb:YAG, quasi-three-level laser, direct pumping, diodepumped, beam quality, highly doped, M2 factor(Received June 20, 2006; accepted July 10, 2006; published online July 28, 2006)

The evolution of InAs wetting layer growth on GaAs(001) was
observed at 500ºC using scanning tunneling microscope within a molecular beam epitaxy growth chamber. In a series of island nucleation andstep flow growth of InAs are clearly observed in the same region witheach snapshot. The step density was increased with increasing of InAs
growth due to island nucleation and recovered within one monolayer (ML)growth with coalescent with two-dimensional islands. Actual step flow
growth was stopped beyond 1ML and then InAs quantum dots (QDs)
were appeared at 1.72ML. It is found that the excess amount of 3.9×
1014cm-2 In adatom independent from chemical bonding might be participate the formation of QDs induced with drastically around 1.7ML.
[DOI : 10.1143/JJAP.45.L777]
Keywords: in situ, molecular beam epitaxy, InAs, GaAs, scanningtunneling microscope, wetting layer, quantum dots,
RHEED
1 Nanoelectronics Collaborative Research Center, IIS, University of Tokyo, 4-6-1 Komaba,
Meguro-ku, Tokyo 153-8505, Japan
2 Advanced Technology R&D Center, Mitsubishi Electric Corporation, 8-1-1
Tsukaguchihonmachi, Amagasaki, Hyogo 661-8661, Japan* Present address: Department of Materials Science and Technology, Nagaoka University ofTechnology, Nagaoka 940-2188, Japan** Corresponding author. E-mail address: tsukamot@iis.u-tokyo.ac.jp

20

JSAP International No.15 (January 2007)

Sadao Uemura and Kenji Torizuka(Received July 10, 2006; accepted July 27, 2006; published online August 11, 2006)

Photonics Research Institute, National Institute of Advanced Industrial Science and Technology(AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, JapanAbstracts of Express Letters

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L867-L870
Part 2, No. 33, 25 September 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L920-L922
Part 2, No. 35, 25 September 2006
©2006 The Japan Society of Applied Physics

Availability of Liquid Crystalline Molecules for
Polycrystalline Organic Semiconductor Thin
Films

Monolithic Implementation of Elemental
Devices for Optoelectronic Integrated Circuitin Lattice-Matched Si/III – V – N Alloy Layers

Hiroaki Iino and Jun-ichi Hanna*

Yuzo Furukawa*, Hiroo Yonezu, Yuji Morisaki, Soo-Young Moon, Seigi
Ishiji and Akihiro Wakahara(Received June 25, 2006; accepted July 31, 2006; published online August 18, 2006)

We have characterized the crystallographic features and charge
carrier transport properties of polycrystalline films of both triphenylene and terthiophene derivatives, which are representative materialsof discotic (disc-like) and calamitic (rod-like) liquid crystals, respectively.
Because of the enhanced anisotropy with the hydrocarbon chains intheir molecular structure and the pre-ordered molecular alignment in themesophase, polycrystalline films of liquid crystals, which exhibit a particular texture indicating that the molecular alignment in the liquid-crystalline phase is well preserved, suppresses the formation of grain boundaries across conduction channels and exhibit clear hole transport even inseveral-µm-thick films. The present results indicate that liquid-crystalline
molecules are good candidates for preparing quality organic polycrystalline semiconductor thin films for optoelectronic applications.
[DOI : 10.1143/JJAP.45.L867]
Keywords: organic polycrystal, discotic liquid crystal, smectic liquid
crystal, grain boundaries, mobility, time-of-flight
Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, J1-2, 4259
Nagatsuta, Midori-ku, Yokohama 226-8503, Japan* E-mail address: hanna@isl.titech.ac.jp(Received July 22, 2006; accepted August 13, 2006; published online September 1, 2006)

Light emitting diodes (LEDs) and Si-based metal oxide semiconductor
field effect transistors (MOSFETs) were monolithically merged in a single
chip which consisted of a Si layer and an InGaPN/GaPN double heterostructure layer lattice-matched to Si grown on a Si substrate by dislocation-free growth process for the first time. The developed fabrication
process was conformed to a conventional planar MOSFET process. All
LEDs and MOSFETs operated normally. Light emission from the LED wasmodulated by switching the MOSFET. The growth and fabrication technologies could be effective for realizing monolithic optoelectronic integrated circuits for massively parallel processing and optical interconnections. [DOI : 10.1143/JJAP.45.L920]
Keywords: optoelectronic integrated circuit, MOSFET, light emitting diode, Si, III – V – N alloy, lattice-matching, device
process
Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan* E-mail address: furukawa@eee.tut.ac.jp

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L894-L897
Part 2, No. 34, 25 September 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L923-L925
Part 2, No. 35, 25 September 2006
©2006 The Japan Society of Applied Physics

Optical Buffer Memory Using
Polarization-Bistable Vertical-Cavity
Surface-Emitting Lasers

Terahertz Plasma Waves in Gated Graphene
Heterostructures

Hitoshi Kawaguchi1,2,*, Takashi Mori2, Yuuki Sato2 and Yasuhiro
Yamayoshi3(Received July 28, 2006; accepted August 9, 2006; published online August 25, 2006)

A novel optical buffer memory with shift register function is
proposed. The buffer consists of a two-dimensional array of polarizationbistable vertical-cavity surface-emitting lasers (VCSELs), in which the bit
state of the optical signal, “0” or “1” is stored as a lasing linear polarization state of 0 or 90º. One-bit optical buffering which is an essential partof the memory, is experimentally demonstrated for the first time using a
980nm polarization-bistable VCSEL having a mesa structure.
[DOI : 10.1143/JJAP.45.L894]
Keywords: optical buffer, optical flip-flop, bistability, polarization,
vertical-cavity surface-emitting laser (VCSEL)
1 Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma,
Nara 630-0192, Japan
2 CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
3 Faculty of Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan* E-mail address: khitoshi@ms.naist.jp

Victor Ryzhii(Received August 9, 2006; accepted August 15, 2006; published online September 1, 2006)

Plasma waves in graphene-based heterostructures with massless (neutrino-like) two-dimensional electron gas and with a highly
conducting substrate (n+-Si) serving as a gate and an isolating gate layer(SiO2) are studied. Using the developed model, we show that the sufficiently long plasma waves exhibit a linear (sound-like) dispersion withthe wave velocity determined by the gate layer thickness and the gate
voltage. The plasma wave velocity in graphene heterostructures cansignificantly exceed the plasma wave velocity in the commonly employedsemiconductor gated heterostructures. The gated graphene heterostructures can be used in different novel voltage tunable THz devices which
utilize the plasma waves. [DOI : 10.1143/JJAP.45.L923]
Keywords: graphene, two-dimensional electron gas, plasma wave,
terahertz range
Computer Solid State Physics Laboratory, University of Aizu, Aizu-Wakamatsu, Fukushima
965-8580, Japan

JSAP International No.15 (January 2007)21

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L926-L928
Part 2, No. 35, 25 September 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L957-L959
Part 2, No. 36, 25 September 2006
©2006 The Japan Society of Applied Physics

Microanalysis of Brownian Particles andReal-Time Nanometer Vibrometry with aLaser-Diode-Pumped Self-Mixing Thin-Slice
Solid-State Laser

Ferromagnetism in Transparent Thin Films of
Fe-Doped Indium Tin Oxide

Seiichi Sudo, Yoshihiko Miyasaka1, Koji Kamikariya1, Kana Nemoto and
Kenju Otsuka1

Takahiro Ohno, Toshio Kawahara, Hidekazu Tanaka, Tomoji Kawai,
Masaoki Oku1, Koichi Okada2 and Shigemi Kohiki2(Received August 17, 2006; accepted August 24, 2006; published online September 8, 2006)

Doppler particle sizing by self-mixing laser was demonstrated byusing a laser-diode-pumped thin-slice Nd:GdVO4 laser with extreme
optical sensitivity. A substantial improvement of optical frequency shifters
led to quick and accurate sizing of Brownian particles with concentration
as low as 50 parts per billion (ppb) for 262-nm polystyren latex spheresin water. A successful real-time measurement of sub-nanometer vibrations was also demonstrated with the present self-mixing laser.
[DOI : 10.1143/JJAP.45.L926]
Keywords: laser-diode-pumped, thin-slice Nd:GdVO4 laser, selfmixing laser, particle sizing, microanalysis, real-time
vibrometry

Transparent films of Fe-doped indium tin oxide (ITO) were grownat oxygen pressures of 5, 1, 10-1, 10-2, and 10-3Pa on yttria-stabilized
zirconia (001) substrates by a pulsed-laser deposition method. We
observed X-ray diffraction peaks from (00h) planes of In2O3 crystalline
phase for the films. The films grown at 5 and 1Pa were paramagnetic
and semiconducting, that at 10-1,Pa was ferromagnetic and semiconducting, and those at 10-2 and 10-3Pa were ferromagnetic and metallic.
The Fe-ITO films grown below 10-1,Pa exhibited room-temperature (RT)ferromagnetism. Nanoscale Fe clusters in the highest oxidation state suchas γ-Fe2O3 resulted in the RT ferromagnetism.
[DOI : 10.1143/JJAP.45.L957]
Keywords: Fe-doped ITO, ITO, thin film, PLD, ferromagnetism,
Fe2O3, cluster

Department of Physics, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa 259-1292,
Japan
1 Department of Human and Information Science, Tokai University, 1117 Kitakaname,
Hiratsuka, Kanagawa 259-1292, Japan

Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
1 Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
2 Department of Materials Science, Kyushu Institute of Technology, Kitakyushu, Fukuoka
804-8550, Japan

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L929-L931
Part 2, No. 35, 25 September 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L960-L962
Part 2, No. 36, 25 September 2006
©2006 The Japan Society of Applied Physics

Quenching Mechanism of MechanicallyCompressed Green Fluorescent Protein
Studied by CASSCF/AM1

Nonlinear Optical Properties of HydrogenatedAmorphous Si Films Probed by a Novel Z-Scan
Technique(Received August 8, 2006; accepted August 17, 2006; published online September 1, 2006)

Qi Gao*, Katsuori Tagami1, Masamichi Fujihira and Masaru Tsukada1

Naoki Minamikawa and Keiji Tanaka(Received July 23, 2006; accepted August 13, 2006; published online September 1, 2006)(Received July 25, 2006; accepted August 22, 2006; published online September 8, 2006)“Atomic force microscopy (AFM) compression simulation” approach
together with “CASSCF/AM1 ONIOM” model calculation method is used
for investigating the quenching mechanism of the luminescence in green
fluorescent protein (GFP). Our results show that the electronic properties and steric conformations of the chromophore’s neighboring residues
strongly influence the photo decay behaviors in GFP.
[DOI : 10.1143/JJAP.45.L929]
Keywords: afm, gfp, quenching, CASSCF, ONIOM

Two-photon absorption coefficient β and intensity-dependent
refractive-index n2 at a wavelength of 1.06µm in hydrogenated amorphous Si films have been evaluated using an imaging-type Z-scan technique. Obtained β and n2 are 3000cm/GW and 0.006cm2/GW, which arecompared with others and discussed in light of a relation proposed by
Sheik-Bahae et al. for crystalline semiconductors. Potential of the film to
optical communication devices is pointed out.
[DOI : 10.1143/JJAP.45.L960]
Keywords: amorphous Si, nonlinear optics, Z-scan, optical device

Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226-8501, Japan
1 Department of Nanoscience, and Nanoengineering, Graduate School of Science and Engineering, Waseda University, 513 Waseda Tsurumaki-cho, Shinjuku-ku, Tokyo 162-0041,
Japan* E-mail address: caoch@cherry.bio.titech.ac.jp

22

JSAP International No.15 (January 2007)

Department of Applied Physics, Graduate School of Engineering, Hokkaido University, Kita-ku,
Sapporo 060-8628, JapanAbstracts of Express Letters

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L963-L965
Part 2, No. 36, 25 September 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L991-L994
Part 2, No. 37, 25 October 2006
©2006 The Japan Society of Applied Physics

Phonon Wavepacket Scattering Dynamics in
Defective Carbon Nanotubes

Lowering the Switching Current of ResistanceRandom Access Memory Using a Hetero
Junction Structure Consisting of Transition
Metal Oxides

Naoaki Kondo1, Takahiro Yamamoto1,2,* and Kazuyuki Watanabe1,2(Received August 11, 2006; accepted August 24, 2006; published online September 8, 2006)

Phonon wavepacket propagation in defective carbon nanotubes
has been investigated through molecular dynamics simulations. We
have demonstrated that the wavepacket scattering method enable thephonon transmission function of carbon nanotubes to be determened
with high accuracy. We have also found that the influence of phonondefect scattering increases with decreasing tube diameter, especially inthe case of high-frequency phonons. These results are in excellent agreement with those obtained by Green’s function calculations.
[DOI : 10.1143/JJAP.45.L963]
Keywords: phonon wavepacket, molecular dynamics, carbon
nanotube, phonon-defect scattering
1 Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo
162-8601, Japan
2 CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama
332-0012, Japan* E-mail address: takahiro@rs.kagu.tus.ac.jp

Kentaro Kinoshita*, Tetsuro Tamura, Masaki Aoki, Yoshihiro Sugiyama
and Hitoshi Tanaka(Received July 12, 2006; accepted August 22, 2006; published online September 15, 2006)

Both lowering the “reset” current of resistance random accessmemory (ReRAM) and raising the resistance in the low resistance state
are crucial for practical use of ReRAM. These requirements have beensatisfied by using a hetero junction structure consisting of transition
metal oxides, NiOy / TiOx / Pt, combining direct contact with the NiOy
using a W-probe. It is considered that this configuration brought about
extreme downsizing of the effective area of both the top and bottom
electrodes for NiOy and thus decreased the number of filaments formedin “forming” process. Reducing the number of filaments is essential tothese issues. [DOI : 10.1143/JJAP.45.L991]
Keywords: ReRAM, NiO, TiO2, forming, reset
Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0197, Japan* E-mail address: Kinoshita.kenta@jp.fujitsu.com

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L966-L969
Part 2, No. 36, 25 September 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L995-L997
Part 2, No. 37, 25 October 2006
©2006 The Japan Society of Applied Physics

Implantation of Perylene Molecules into Glass
Plates through a Water Layer Using a Laser
Induced Molecular Micro-Jet

Realization of Large Open-Circuit
Photovoltage in Organic Thin-Film Solar Cells
by Controlling Measurement Environment

Masahiro Goto, Yuriy Pihosh, Akira Kasahara and Masahiro Tosa

Tetsuya Taima*, Jun Sakai1, Toshihiro Yamanari and Kazuhiro Saito(Received July 25, 2006; accepted August 24, 2006; published online September 8, 2006)(Received August 21, 2006; accepted September 4, 2006; published online September 15, 2006)

Perylene molecules have been successfully implanted onto borosilicate glass plates, forming fluorescent features of 420 nm in diameter, using a method involving laser induced molecular micro-jet ejection
through a water layer. The technique utilises a polymer source film inwhich perylene molecules are dispersed, a borosilicate glass substrate asa target and a pulsed laser. The space gap between the source film andthe target is filled with liquid water. Perylene molecules dispersed in thepolymer source films are photo-excited using 4-ns laser pulses resulting
in the ejection of the molecules from the source matrix after which they
become implanted into the target after passing through the water layer.
This new advanced implantation method, using a laser induced molecular micro-jet through water, gives fine spatial control for fixing functional organic molecules in a designated region on hard dielectric materials and will have application in the fabrication of molecular devices,molecular sensors, and opto-electronics. [DOI : 10.1143/JJAP.45.L966]
Keywords: perylene, water, pulsed laser, molecular implantation,
molecular jet

To obtain large open-circuit photovoltage (Voc), we introduced ap -type semiconductor 5,6,11,12-tetraphenylnaphthacene (rubrene),
which has a highest occupied molecular orbital (HOMO) level of 5.4eV.
Owing to an adsorption of O2 and H2O into rubrene film, optical absorption peaks were markedly decreased after exposure in air. By controllingthe measurement environment to prevent the adsorption of O2 and H2O
into rubrene films, we could obtain a high-performance organic thin-film
solar cell with a large Voc of 0.91V. [DOI : 10.1143/JJAP.45.L995]
Keywords: organic thin-film solar cell, organic photovoltaic cell,organic semiconductor, open-circuit photovoltage,rubrene, C60
Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
1 Advanced Technologies Development Laboratory, Matsushita Electric Works, Ltd., 1048
Kadoma, Osaka 571-8686, Japan* Corresponding author. E-mail address: tetsuya-taima@aist.go.jp

Materials Reliability Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba,
Ibaraki 305-0047, Japan

JSAP International No.15 (January 2007)23

Abstracts of Express Letters

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L1022-L1024
Part 2, No. 38, 25 October 2006
©2006 The Japan Society of Applied Physics

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L1042-L1044
Part 2, No. 39, 25 October 2006
©2006 The Japan Society of Applied Physics

Negative Ion Transfer Model of
Low-Temperature Oxidation of Silicon Surface
by High-Density Microwave Plasma

High-Efficiency Excitonic Emission with
Deep-Ultraviolet Light from (001)-Oriented
Diamond p – i – n Junction

Isahiro Hasegawa1,2,* Takeshi Yamauchi3 and Hideo Sugai2

Toshiharu Makino1,2,*, Norio Tokuda1,2, Hiromitsu Kato1,2, Masahiko
Ogura1,2, Hideyuki Watanabe1,2, Sung-Gi Ri1,2, Satoshi Yamasaki1,2,3 andHideyo Okushi1,2(Received August 30, 2006; accepted September 8, 2006; published online September 22, 2006)

High-quality thin SiO2 layer is rapidly formed at low temperature(~400ºC) by oxidation of silicon wafer using high-density microwave
plasma in argon containing a few % O2. The oxidation rate is proportional to the square root of electron density but hardly correlates withthe measured O radical density. Secondary ion mass spectrometry (SIMS)
depth analysis of SiO2 layer with 18O as an isotope tracer suggests that
predominant mobile species in the oxide layer is not neutral oxygen
atom but oxygen negative ion, possibly O2-, as proposed by Jorgensen
and Mott. The time evolution of oxidation process calculated in a negative ion transfer model well explains the experimental observation andaccounts for the square root dependence on the electron density.
[DOI : 10.1143/JJAP.45.L1022]
Keywords: plasma oxidation, microwave plasma, radical, siliconoxidation, negative ion, Jorgensen – Mott model
1 Procurement Division, Semiconductor Company, Toshiba Corporation, 1-1-1 Shibaura,
Minato-ku, Tokyo 105-8001, Japan
2 Department of Electrical Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya
464-8603, Japan
3 Corporate Manufacturing Engineering Center, Toshiba Corporation, 33 Shin-isogo-cho,
Isogo-ku, Yokohama 235-0017, Japan* Corresponding author. E-mail address: isahiro.hasegawa@toshiba.co.jp

Jpn. J. Appl. Phys. Vol. 45 (2006) pp. L1025-L1026
Part 2, No. 38, 25 October 2006
©2006 The Japan Society of Applied Physics

High-Brightness Narrow-Bandwidth
Operation of a Broad-Area Laser Diode witha Rear External Cavity
Yujin Zheng*, Akiyoshi Watanabe, Takenori Morita and Hirofumi Kan(Received August 28, 2006; accepted September 4, 2006; published online September 22, 2006)

We demonstrate a high-brightness, narrow-bandwidth, broad-arealaser diode with a rear external cavity that consists of a micro-cylindricallens and a volume Bragg grating in the rear facet of the diode. Using
this external-cavity technique, a broad-area laser diode achieved a bandwidth’s full width at half-maximum (FWHM) of 0.22nm and a divergenceangle (FWHM) of 1.1º with an output power of 446mW.
[DOI : 10.1143/JJAP.45.L1025]
Keywords: broad-area laser diode, volume Bragg grating, external
cavity, bandwidth, divergence angle
Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamamatsu,
Shizuoka 434-8601, Japan* E-mail address: y-zheng@crl.hpk.co.jp

24

JSAP International No.15 (January 2007)(Received July 26, 2006; accepted September 8, 2006; published online September 29, 2006)

We have realized high-efficiency excitonic emission with deep-UV
light at room temperature for a (001)-oriented diamond light-emitting
diode with an intrinsic diamond layer as an active region. The borondoped p -type, non-doped intrinsic, and phosphorus-doped n -type( p – i – n ) junction diode structure was formed by applying an optimized homoepitaxial growth technique based on microwave plasmaenhanced chemical vapor deposition. High-performance p – i – n junction
characteristics were confirmed from current – voltage and capacitance –voltage properties. A strong UV light emission at around 240nm due tofree exciton recombination was observed at a forward current of over
6mA, while the broad visible light emission from deep levels was significantly suppressed compared to that of reported electroluminescence indiamond p – n junctions. [DOI : 10.1143/JJAP.45.L1042]
Keywords: diamond, chemical vapor deposition, p – i – n junction,light-emitting diode, exciton
1 Diamond Research Center, National Institute of Advanced Industrial Science and Technology(AIST), Tsukuba Center 2, Tsukuba, Ibaraki 305-8568, Japan
2 Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), c/o AIST, Tsukuba, Ibaraki 305-8568, Japan
3 Graduate School of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki
305-8577, Japan* E-mail address: toshiharu-makino@aist.go.jp