bluuebunny/crossref_metadata_2025 huggingface dataset:
Zn-Diffusion-Induced Disordering of InGaAs/AlGaInAs Multiple Quantum Well and Its Application to Long-Wavelength Laser
Authors: Goto Katsuhiko , Uesugi Fumito , Takahashi Shogo , Takiguchi Toru , Etsuji Omura Etsuji Omura , Yutaka Mihashi Yutaka Mihashi
Published: October 2002

Zn-diffusion-induced disordering of the InGaAs/AlGaInAs multiple quantum well (MQW)
is investigated as a new processing technique for long-wavelength optoelectronic devices.
Complete disordering of the MQW structure is confirmed through the observation of the
shortening of the photoluminescence peak wavelength and secondary ion mass spectroscopy
(SIMS) measurement. Lattice-matched disordering is also confirmed with X-ray diffraction.
A long-wavelength buried-MQW laser is fabricated for the first time, in which index-waveguide and
carrier confinement are obtained by disordering. The pulsed oscillation at room temperature is achieved near
1.56 µ m.
Femtosecond Erbium-Doped Fiber Laser with Nonlinear Polarization Rotation and Its Soliton Compression
Authors: Yoshida Eiji , Yasuo Kimura Yasuo Kimura , Masataka Nakazawa Masataka Nakazawa
Published: October 2002

A continuous wave suppressed, uniformly repetitive pulse train as short as
136–145 fs has been successfully generated at a wavelength of 1.55 µ m from
a new type of femtosecond erbium-doped fiber laser with nonlinear polarization rotation.
The 145 fs pulse was shortened to 52 fs by using soliton narrowing and high order
soliton compression. Soliton narrowing was achieved by amplifying the soliton pulse
with an erbium-doped fiber amplifier, and a short length of dispersion-flattened fiber
was used for further compressing the soliton.
Emission Properties of InGaAlP Visible Light-Emitting Diodes Employing a Multiquantum-Well Active Layer
Authors: Sugawara Hideto , Kazuhiko Itaya Kazuhiko Itaya , Gen-ichi Hatakoshi Gen-ichi Hatakoshi
Published: October 2002

Visible InGaAlP light-emitting diodes (LEDs) employing a multiquantum-well (MQW)
active layer have been investigated. Photo luminescence measurements showed that
growth on a GaAs substrate, with an intentional surface misorientation from the (100)
plane towards the [011] direction, resulted in a marked improvement in the quality of
the MQW compared with growth on a just (100) substrate. The emission properties of the
LED strongly depended on the various parameters of the MQW structure, in particular
the number of wells. The external quantum efficiency of a 600 nm LED with a 20-well
MQW active layer was found to be 1.6%. The emission wavelength could be further
reduced by 10 nm without any significant decrease in the external quantum efficiency.
Visible Photoluminescence in Highly Photoconductive Hydrogenated Amorphous Silicon Deposited by Glow Discharge of SiH4 Highly Diluted with He
Authors: Akiyama Koji , Akifumi Ogiwara Akifumi Ogiwara , Hisahito Ogawa Hisahito Ogawa
Published: October 2002

A wide-band-gap (> 2.0 eV) hydrogenated amorphous silicon (a-Si:H) film
showing visible photoluminescence (PL) is obtained by rf glow-discharge decomposition
of SiH4 highly diluted with He. The PL and the structural properties of the
a-Si:H are investigated. The He dilution leads to the extension of the band gap and
the increase of the SiH2 and ( SiH2)

n

configurations in the film.
The PL increases rapidly and blue-shifts consistently with the increase of the SiH2
and (SiH2)

n

configurations. By observation using transmission electron
microscopy and Raman scattering, it is found that the film consists of uniform amorphous
structure and includes no microcrystallites. The film exhibits a photoconductivity
(under AM-1 light of 100 mW/cm2) to dark conductivity ratio of over 106
in addition to a visible PL at room temperature. This new a-Si:H film has potential
for application to an optical device with characteristics of both light emission and photosensitivity.
Excitation and Radiative Efficiencies in ZnS:Mn Thin Film Electroluminescent Devices Prepared by Reactive Radio-Frequency Magnetron Sputtering
Authors: Xian Hong , Benalloul Paul , Charles Barthou Charles Barthou , Jacques Benoit Jacques Benoit
Published: October 2002

Thin film electroluminescent (EL) devices have been prepared by reactive radio-frequency
magnetron sputtering. The excitation efficiency η exc and the radiative efficiency
η rad have been studied by analyzing the light response of the devices under
short-pulse excitations. The influence of the preparation conditions on these partial
efficiencies has been examined systematically. Partial efficiency measurements not only
provide a method to characterize the quality of the active layer, but also permit us to
obtain enlightening information on the electro-optical properties of the EL devices prepared by sputtering.
Surface Structures and Photoluminescence Mechanisms of Porous Si
Authors: Suda Yoshiyuki , Ban Takuya , Koizumi Tomohiro , Koyama Hideki , Tezuka Yasuhisa , Shin Shik , Nobuyoshi Koshida Nobuyoshi Koshida
Published: October 2002

The position of the valence hand maximum, the Si 2p core level and the Si L
I
I,I
I
I
threshold of porous Si (PS) have heen simultaneously measured using a synchrotron radiation photoemission technique. The measured surface optical gap is strongly correlated to the photoluminescence (PL) peak energy, indicating that the surface atomic configuration is related to the PL origin. Freshly prepared PS exhibits a monohydride surface and contains almost no oxygen. The amount of surface oxygen does not correlate with the PL intensity. From these results, it is concluded that oxide compounds including siloxene are excluded from the candidates for the PL origin. Thus, surface oxides of PS act as secondary effects in the PL mechanisms and well-qualified surface oxidation is concluded to lead to efficient electron-hole confinement. Surface energy-band diagrams of freshly prepared PS and partially oxidized PS have been analyzed using the valence, core and total yield spectra. These band diagrams are explained well in terms of band quantization induced by quantum-sized crystallites formed in the surface region of PS.
Spectroscopic-Ellipsometry and Thermoreflectance Spectra of Sputter-Deposited InSb Films
Authors: Takayuki Miyazaki Takayuki Miyazaki , Sadao Adachi Sadao Adachi
Published: October 2002

Spectroscopic-ellipsometry (SE) and thermoreflectance (TR) spectra of InSb films
sputter-deposited on sapphire substrates are reported. Measurements are made on the
same crystal in the 1.5–5.5-eV photon energy range at room temperature. These data
are analyzed on the basis of a simplified model of the interband transitions. Results
are in satisfactory agreement with the experimental data over the entire range of photon
energies. The finding definitely links the temperature-induced change in the dielectric
function (TR) to the first derivative of the dielectric function (SE).
Radiation Properties of Silicon Metal-Oxide-Semiconductor Structures with Zinc-Doped Oxides
Authors: \.zek Tomasz Bro , Didenko Piotr I. , Kiblik Vasilij Y. , Logush Oleg I. , Litovchenko Vladimir G. , Romanova Galina F.
Published: October 2002

In this paper we present the results of investigation of radiation-induced effects in metal-oxide-semiconductor (MOS) structures with oxides doped with moderate amounts of zinc during the oxide growth. It is shown through secondary ion mass spectroscopy (SIMS) analysis that zinc, when present in the oxidation ambient, is effectively incorporated into the oxide matrix. Electrophysical parameters of the modified MOS structures are similar to those of the reference ones. On the other hand, radiation sensitivity of zinc-doped structures is significantly affected. While observing an enhanced radiation-induced positive charge buildup, we have found that the Si-SiO2 interface and the near-surface silicon region were significantly hardened in these structures. The observed effects strongly depend on the amount of zinc incorporated in the oxide. It is also shown that postirradiation low-temperature annealing can result in the improvement of the oxide and the Si-SiO2 interface characteristics. The main parameters characterizing the system, namely, the oxide charge, the density of interface states, and the minority carrier generation lifetime, are improved after the irradiation-then-annealing treatment compared to those of simply postmetallization-annealed MOS structures. A simple model to explain the observed radiation-induced ordering effect is also presented.
Ferro- and Pyroelectricity in Amorphous Polyphenylethernitrile
Authors: Tasaka Shigeru , Takatoshi Toyama Takatoshi Toyama , Norihiro Inagaki Norihiro Inagaki
Published: October 2002

Ferroelectric properties of polyphenylethernitrile were investigated in the temperature
range of 20°C to 240°C. Typical electric displacement-electric
field ( D-E) hysteresis was observed only in the quenched sample. The remanent
polarization and the coercive field at 115°C (0.1 Hz) were about 10 mC/m2
and 75 MV/m, respectively. A broader X-ray diffraction pattern from the quenched
sample suggested a typical amorphous state. This sample was found to have a large
remanent polarization (∼ 70 mC/m2) by poling near the glass transition
temperature and a large pyroelectric activity (18 µ C/m2K).
Volume Expansion and Ag Doping Amounts in the Photodoping Process in Amorphous As2S3
Authors: Lee Jaeman , Ogawa Tsutomu , Kudo Hiroshi , Arai Toshihiro
Published: October 2002

The behavior of volume expansion in the photodoping phenomenon has been studied
by using Rutherford backscattering, fringes of equal chromatic order and X-ray diffraction
methods. The quantities of volume expansion in the 1st and 2nd stages of photodoping have
been determined as 1.13 and 1.43 on average over the three methods, respectively.
The composition ratios of Ag to As2 have also been determined as 1.30 for the
1st stage of photodoping and 2.38 for the 2nd stage. These values have been discussed
in relation to the lateral diffusion and the diffusion model.
Heteroepitaxial Growth of GaAs on (100) GaAs and InP by Selective Liquid Phase Epitaxy
Authors: Dong-Keun Kim Dong-Keun Kim , Byung-Teak Lee Byung-Teak Lee
Published: October 2002

Experimental conditions to obtain heteroepitaxial (100) GaAs/InP structure were
studied using the selective liquid phase epitaxy (SLPE) technique. It was observed
that maximum epitaxial layer overgrowth (ELO) can be obtained by aligning the growth
seed along the 75° off [011] direction. The ELO width decreased as the mask width
decreased, probably due to As depletion above the oxide mask, which could be partly
compensated by convecting the melt. The ELO width was substantially increased by adding Si,
P or Se to the Ga growth melt. Se addition, in particular, prevented meltback of
substrates during the growth of GaAs on InP, resulting in a continuous specular GaAs film.
Cross-sectional transmission electron microscopy (TEM) study of the layers revealed
that propagation of the misfit dislocations at the GaAs/InP interface is effectively
suppressed by the presence of the SiO2 mask, except for some dislocations that
propagate toward the top of the mask by bending at the mask edge.
Formation of Cubic Carbon by Dynamic Shock Compression of a Diamond/Amorphous Carbon Powder Mixture
Authors: Günther Burkhard Günther Burkhard , Koji Dan Koji Dan , Yasuhiro Tanabe Yasuhiro Tanabe , Akira B. Sawaoka Akira B. Sawaoka , Kenjiro Yamada Kenjiro Yamada
Published: October 2002

A diamond/amorphous carbon powder mixture was shock-compressed by a
rod-in-cylinder method. Characterization by high-resolution electron
microscopy (HREM) revealed the formation of several carbon
modifications. Beside a large amount of graphite, two cubic phases of carbon,
turbostratic carbon and chaoite were detected in small quantities.
Different phase transition mechanisms were proposed. High temperatures and
high pressures in the powder sample resulted in the transformation of
amorphous carbon into graphite. One
cubic phase corresponded to a modification of diamond (n-diamond)
in a previous report determined by observation of the forbidden {200},
{222} and {420} reflections of cubic diamond. We related the presence of
these reflections not to cubic diamond, but to a carbon form with a
face-centered-cubic (fcc) lattice formed by local melting of the
diamond surface and subsequent rapid quenching, and via a
solid-vapor-liquid-solid (SVLS) path of phase transitions in
amorphous carbon particles. The second cubic phase originated from the
deposition of a gaseous or liquid carbon jet on diamond. The lattice
parameter was calculated to a
o = 0.432 nm.
Synthesis of BaTiO3/LaNiO3 and PbTiO3/LaNiO3 Multilayer Thin Films by Spray Combustion Flame Technique
Authors: Ichinose Hiromichi , Shiwa Yuzo , Masamitsu Nagano Masamitsu Nagano
Published: October 2002

In an attempt to utilize LaNiO3 thin film as a bottom electrode for
ferroelectric BaTiO3 and PbTiO3 thin films, PbTiO3/LaNiO3
and BaTiO3/LaNiO3 multilayer thin films were prepared on MgO(100) by
spraying an ultrasonically atomized nitrate solution into a combustion flame (spray
combustion flame technique). Highly oriented BaTiO3(100)/LaNiO3(100) and PbTiO3(001)/LaNiO3(100)
multilayer thin films were obtained on MgO(100). BaTiO3 film was pseudocubic while
PbTiO3 film was tetragonal. Curie temperature measurement of the PbTiO3
film suggested that the films were free from contamination when LaNiO3 was used as a bottom electrode.
Deposition of LaMO3 (M=Ni,Co,Cr,Al)-Oriented Films by Spray Combustion Flame Technique
Authors: Ichinose Hiromichi , Shiwa Yuzo , Masamitsu Nagano Masamitsu Nagano
Published: October 2002

LaMO3 (M=Ni,Co,Cr,Al) films were prepared on sintered alumina, sapphire
(001) and MgO(100) at 500–900°C by spraying ultrasonically atomized
aqueous solutions of nitrates into a combustion flame (spray combustion flame technique).
LaNiO3 and LaCoO3 on MgO(100) crystallized in high-temperature
phases (cubic) while LaCrO3 and LaAlO3 crystallized in room-temperature phases.
LaMO3 (M=Ni,Co,Cr,Al) films on MgO(100) were highly oriented to (100), (100),
(001) and (100), respectively, while the films on sintered alumina and sapphire were not.
The electric resistivities of the dense LaMO3 (M=Ni,Co,Cr) films were as low
as those of bulk ceramics. LaNiO3 film deposited on MgO above 700°C
showed the lowest resistivity of about 6×10-6 Ω m. It was
suggested that the reactivities of the constituent metal atoms with OH in the flame
are associated with the preferred phase and the morphology of the films.
In Situ Measurements of Drastic Change of Electrical Conductivity and Structure upon Electrochemical Lithium Intercalation in Pyrolyzed Poly(hydrazocarbonyl-1-4-phenylenecarbonyl) Film
Authors: Roh Young Bae , Kawai Tsuyoshi , Araki Hisashi , Yoshino Katsumi , Takase Masaaki , Banjyo Takashi , Miyai Kiyoshi , Tokuda Nobuyuki
Published: October 2002

Drastic changes of structure and electrical property of pyrolyzed polymers based
on poly(hydrazocarbonyl-1,4-phenylenecarbonyl) (poly(terephthalohydrazide)) film have
been investigated in an electrochemical cell with 1 M LiClO4 in a 70:30 mixture
of propylene carbonate and 1,2-dimethoxyethane as the electrolyte, by means of in situ
measurement techniques using the four-probe conductivity measurement method and X-ray
diffraction method with a beryllium window. In the first redox cycle, the highly crystallized
graphite prepared by pyrolysis at 2800°C exhibits large irreversible changes
in both apparent conductivity and the layered structure, whereas the poorly crystallized
carbon prepared by pyrolysis at 1300°C showed a good reversible change in
structure but a large decrease in conductivity compared with that of the pristine sample.
The two characteristic X-ray diffraction peaks of the distorted graphite layer observed
only in the first discharge are attributed to the decomposition reaction of electrolyte
and lithium ions in graphite layers. The passivation film formed on the surface by the
first discharge also affects the characteristics. In the film prepared by pyrolysis at
1300°C, damage of disordered carbon layer structures occurred in the first
charge process. The apparent diffusion coefficient of lithium in the disordered carbon
was larger than that in graphite, and was activated with increasing number of cycles,
while that of graphite was independent of the number of cycles.
Thermochromic Properties of Mixture Systems of Octadecylphosphonic Acid and Fluoran Dye
Authors: Tsutsui Kyoji , Sato Takehito Yamaguchi
Published: October 2002

We have examined the thermochromic behavior of thin films formed by mixing a fluoran dye
(FD: 2′-( o-chloroanilino)-6′-di- n-butylaminospiro[isobenzofuran-1(3 H),9′-[9 H]xanthene]-3-one)
and octadecylphosphonic acid (P18). The coloring and discoloring states were revealed
to be controllable by changing the rate of cooling from the colored mixture liquid
( 100°C); quenching at 0°C maintained the solidified colored state,
yet discoloring occurred after slow cooling at the rate of 4°C/min.
We confirmed by X-ray diffraction and FT-IR spectra that the solidified colored state
is produced by formation of the supramolecules, in which seven molecules of P18 and one
molecule of FD combined, whose aggregates are in a lamellar structure. In the discoloring state,
the supramolecule is decomposed to P18 and FD due to the fractional crystallization of P18.
Role of Helicon Waves on High-Density Plasma Production
Authors: Yasuyoshi Yasaka Yasuyoshi Yasaka , Yoshiaki Hara Yoshiaki Hara
Published: October 2002

Plasma production by rf fields in the helicon wave frequency range is investigated by using the rotating field antenna which can select the azimuthal mode number of the applied rf. The calculated dispersion relation shows that them= -1 mode helicon wave propagates whereas them=+1 mode helicon wave is cut off. The produced helium plasma density in the case of them= -1 mode rf application is 1 ×1013cm-3, which is more than 5 times greater than in the case of them= +1 mode rf application. The two-dimensional numerical simulation of the rf plasma production also qualitatively gives the same result as in the experiment. The plasma for them= +1 mode rf is sustained by the antenna near field, while for them= -1 mode rf, it is sustained by the power absorption from the propagating helicon wave. From both the experiment and the simulation, the helicon wave is revealed to increase the plasma density from the order of 1012cm-3to 1013cm-3by efficient power deposition to electrons.
Correlation between CH3Radical Density and Carbon Thin-Film Formation in RF Discharge CH4Plasma
Authors: Susumu Naito Susumu Naito , Nobuei Ito Nobuei Ito , Tadashi Hattori Tadashi Hattori , Toshio Goto Toshio Goto
Published: October 2002

The CH3radical density and the deposition rate of carbon thin film were measured under the same conditions in RF-discharge CH4and CH4/rare gas plasmas. The behavior of the CH3radical density showed a similar tendency as the deposition rate of carbon thin film as a function of power and CH4pressure in CH4plasma. In CH4/Xe plasma, where a selective formation mechanism increases the CH3radical density with increasing Xe dilution whereas other CHxradicals are expected to decrease, the carbon deposition rate increased with increasing Xe dilution. These results strongly suggest that the CH3radical is the dominant precursor in the film formation. The increase of film formation rate in CH4/Xe plasma was slower than that of the CH3radical density with increasing Xe dilution. This could be attributed to the sputtering of the film by heavy Xe ions. In CH4/He plasma, where the effect of sputtering is expected to be small, the film deposition rate and the CH3density varied in a much more similar manner.
New Type of End-Loss Energy Component Analyzer and Velocity Distribution Function of End-Loss Ions in Tandem Mirror
Authors: Kameo Ishii Kameo Ishii , Toshiaki Tanaka Toshiaki Tanaka , Toshitaka Nakada Toshitaka Nakada , Takehiro Katori Takehiro Katori , Akira Abe Akira Abe , Toshiki Takahashi Toshiki Takahashi , Isao Katanuma Isao Katanuma , Akiyosi Itakura Akiyosi Itakura , Kiyoshi Yatsu Kiyoshi Yatsu , Teruo Tamano Teruo Tamano
Published: October 2002

A new type of end-loss energy component analyzer (ELECA)
has been developed in order to investigate ion confinement of the
tandem mirror. The essential advantage of the use of the ELECA is the
ability to determine
distribution functions of end-loss ions every moment during plugging
in one shot.
The ELECA was carefully designed, taking account of the influence of
the fringing
electrostatic field and weak leakage magnetic field on ion trajectories
in the analyzer.
The new diagnostics has been applied to the tandem mirror GAMMA 10.
Consequently, it was verified from the viewpoint of ion distribution
in velocity space that
plug potential was created upon turning on electron cyclotron resonance
heating (ECRH) even without sloshing ions caused by neutral beam injection
(NBI), and at the same time,
the structure with double loss boundaries changed to a simple structure.
Gassensitivity of Modified Surfaces of a Surface Acoustic Wave Device by Chemical Adsorption Technique and Langmuir-Blodgett Technique
Authors: Ohnishi Michihiro , Ishibashi Tadashi , Masahiro Aoki Masahiro Aoki , Coe Ishimoto Coe Ishimoto
Published: October 2002

The gassensitivity of a surface acoustic wave (SAW) device with a surface modified
by an organic monolayer is reported. A chemical adsorption technique, as well as a
Langmuir-Blodgett (LB) technique, was used to prepare the gas-sensitive monolayer
on the SAW device. The specific sensitivity of a modified surface for organic gases
was recognized and it was elucidated that the devices could be used in a pattern
recognition system for odoriferous gases. The gas-sensitive monolayer is expected
to realize an electronic nose of ultrasmall scale at low cost.
Anisotropic Etching of Submicronic Resist Structures by Resonant Inductive Plasma Etching
Authors: Etrillard Jackie , Francou Jean-Marc , Inard Alain , Henry Daniel
Published: October 2002

The etching of submicronic resist structures in an oxygen plasma has been investigated in a helicon wave reactor. Systematic investigations have been conducted on the structure profile dependences on ion energy and on plasma pressure. For resist etching, the result of these investigations revealed the considerable heat transfer between the plasma species and the substrate. To obtain anisotropically etched resist structures, it was necessary to cool the wafer holder at low temperature ( -75°C) and reinforce the thermal conduction between the wafer and wafer holder. Comparison of an anisotropic process, obtained with conventional reactive ion etching (RIE), is made in terms of etch rate, sidewall passivation and surface pollution.
Proximity Effect on Patterning Characteristics of Hole Patterns in Synchrotron Radiation Lithography
Authors: Somemura Yoh , Kimiyoshi Deguchi Kimiyoshi Deguchi , Kazunori Miyoshi Kazunori Miyoshi
Published: October 2002

This paper reports the results of analyzing the proximity effect on the patterning
characteristics for plural neighboring hole patterns in synchrotron radiation lithography.
Fresnel diffraction simulation was used and pattern replication experiments were performed
with pattern pitch, proximity gap, and mask contrast as parameters. Even when the pattern
pitch (hole:space) is 1:1, pattern sizes down to 0.2 µ m can be replicated
with a large dose margin under a large proximity gap condition up to 40 µ m,
irrespective of the mask contrast. A low-contrast (2.5) mask has an advantage over the
conventional-contrast (7) mask in that it allows the use of a larger proximity gap
when replicating hole patterns with a size of 0.1–0.2 µ m. Moreover,
the phase-shifting mask we previously proposed improves the exposure latitude and widens
the proximity gap, so that it is possible to use a 20-µ m gap to replicate
0.1-µ m hole patterns for a pitch of 1:1 and to use a 30-µ m gap for a pitch of 1:2.
New Cryostat for Applying Uniaxial Stress
Authors: Yoshihiro Shimazu Yoshihiro Shimazu , Seiichiro Ikehata Seiichiro Ikehata
Published: October 2002

A novel pressure device for applying uniaxial stress is described, which is
used at low temperatures. The uniaxial stress is applied by a spring
immediately adjacent to the sample. The sample stress is precisely determined from the contraction of the spring and the spring constant. The main advantage of this apparatus is that the friction of the pressure-transmitting medium does not cause an uncertainty in the determination of the actual sample stress.
Optical Humidity Sensor Using Fluorescent Plastic Fiber and Its Application to Breathing-Condition Monitor
Authors: Shinzo Muto Shinzo Muto , Hiroshi Sato Hiroshi Sato , Toshiki Hosaka Toshiki Hosaka
Published: October 2002

The plastic fiber humidity sensor, the mechanism of which is based
on an ionization reaction between water vapor and the fluorescent dye-doped
polymer cladding, was studied. The conditions under which to obtain the
maximum sensitivity were derived from the theory and experimental data.
Under these conditions, the fluorescent plastic fiber could be used as an
excellent optical humidity sensor head with good linearity over the wide
humidity range. Due to its reproducibility and fast response property, its
application to a breathing-condition monitor became possible.
Improvement in Hydrogen Photoevolution Efficiency for Platinum-Deposited Indium Phosphide Electrodes by the Removal of Surface States
Authors: Kobayashi Hikaru , Fumiaki Mizuno Fumiaki Mizuno , Yoshihiro Nakato Yoshihiro Nakato
Published: October 2002

Hydrogen photoevolution has been performed using minute platinum (Pt)-island-deposited
p-InP electrodes in an HClO4 solution. The photovoltage for the as-prepared
electrodes is low, but is increased by about 0.5 V after anodic dissolution. The
electrode capacitance is decreased by sweeping the potential in the region where
the anodic dissolution occurs, while it is almost unchanged with the potential sweep
in the region where dissolution does not occur. These results indicate that the surface
states are removed by the anodic dissolution, leading to the increase in the photovoltage.
The Mott-Schottky plot is nominally changed by the anodic dissolution, unlike the
current-voltage curves. This unusual result can be explained by the presence of high- and
low-energy barrier regions in the InP surface before anodic dissolution, the former
area being much larger than the latter.
Relationships between Laser Powers and Photoacoustic Signal Intensities of Flavin Adenine Dinucleotide and β-Carotene Dissolved in Solutions
Authors: Keiichi Imakubo Keiichi Imakubo
Published: October 2002

Ar ion laser-induced photoacoustic spectroscopy has been performed on 0.01 µ M
flavin adenine dinucleotide in H2O and 0.01 µ M β-carotene in
n-hexane where the optical absorption spectroscopy is not applicable. On the basis
of the linear relationships between laser powers and photoacoustic signal intensities
up to 500 mW, it may be concluded that laser power ranging from 10 to 50 mW is
required for the successful observation of photoacoustic signals without any photochemical or photobiological effects.
Enhanced Blue-Light Emission from an Indium-Treated Porous Silicon Device
Authors: Steiner Peter , Kozlowski Frank , Wielunski Marek , Walter Lang Walter Lang
Published: October 2002

We present the technology and the performance of blue-light-emitting porous silicon devices. The devices are
fabricated using porous silicon formation with UV-light applied. Furthermore, indium is electroplated into the pores,
causing an increase of the quantum efficiency. The blue electroluminescence exhibits a peak maximum around 480 nm
and an external quantum efficiency of 0.5×10-2 %. Rutherford backscattering spectroscopy (RBS) was
employed to measure the stoichiometry and the depth profile of indium in the porous layer.
Deep Acceptor Levels in Molecular Beam Epitaxial High Purity p-Type GaAs
Authors: Stillman Seref Kalem
Published: October 2002

Deep acceptor impurities in high-purity, unintentionally p-type doped GaAs epilayers grown by molecular beam epitaxy have been investigated by variable temperature Hall effect measurements. The experimental results were analyzed in detail by using the grand partition function formalism assuming multiple acceptor levels with both single and double occupancy. It is shown that p-type conduction is originated from the presence of a residual shallow acceptor and several deep acceptor levels. For the samples having relatively high concentration of shallow acceptors, deep aeceptor states with the ionization energies of about 90 and 200 meV are determined, which are likely associated with the presence of double acceptor centers. In the high purity samples, however, deeper aceeptor levels are required to account for the data.
Low Temperature Growth of Heavily Carbon-Doped GaAs by Metalorganic Molecular Beam Epitaxy with Elemental Gallium
Authors: Nagao Keisuke , Shirakashi Jun-ichi , Takahashi Makoto Konagai
Published: October 2002

In the growth by metalorganic molecular beam epitaxy (MOMBE) of carbon (C)-doped GaAs, elemental gallium (Ga)
has been introduced in addition to conventional sources, trimethylgallium (TMG) and As4. A drastic increase of
growth rate was obtained, while a high hole concentration was maintained. A hole concentration of
4×1020 cm-3 with the growth rate of 1.1 µ m/h was achieved. Electrical and optical
properties of epilayers are comparable to those of C-doped GaAs epilayers grown with conventional sources.
Furthermore, it is found that the incorporation rate of monomethylgallium (MMG) into a growing epilayer increases
with increasing beam flux of elemental Ga. This is because the decomposition of MMG into Ga is well controlled by
the introduced elemental Ga, maintaining a chemical equilibrium of the steady-state decomposition process of TMG at
the growing surface.
Dependence of Magnetoresistance and Antiferromagnetic Coupling on Growth Orientation and Interface Roughness in Epitaxial Co/Cu Superlattices
Authors: Kingetsu Toshiki , Yoshizaki Fukio
Published: October 2002

Epitaxial Co/Cu superlattices with surface orientations of (111), (100) and (110) were grown by
ultrahigh-vacuum-based dc magnetron sputter deposition to investigate the dependence of magnetoresistance (MR) on
growth orientation. The MR and antiferromagnetic (AFM) coupling were distinctly different in the superlattices of the
three types even when prepared under the same conditions. The roughness of Co/Cu interfaces was found to be the
largest in the (111) samples and the smallest in the (110) samples. A tendency for the MR and AFM coupling to decrease
with decreasing interface roughness was observed in each of the three surface orientations. However, the order of
magnitude of the MR ratio could not be explained in terms of the interface roughness alone.
Effects of Absorption of Nonlinear Optical Crystal on Conversion Efficiency of Cerenkov-Radiation Type Second-Harmonic Generation in Crystal-Cored Fiber
Authors: Umegaki Kiyofumi Chikuma
Published: October 2002

The Cerenkov-radiation-type second-harmonic generation from the nonlinear-optical crystal-cored fiber is
analyzed, when the core crystal absorbs the second-harmonic wave. It is shown that substantial conversion efficiency
can be obtained against relatively large absorption. It is also shown that the crystal-cored fiber can be optimally
designed using only the refractive indices, even if the absorption coefficient is not known.
Frequency Doubling of Tunable Ti:sapphire Laser with KNbO3 in External Cavity
Authors: Hidemi Tsuchida Hidemi Tsuchida
Published: October 2002

Frequency doubling of a tunable Ti:sapphire laser is demonstrated using a noncritically phase-matched
KNbO3 crystal in an external enhancement cavity. A narrow linewidth Ti:sapphire laser is constructed and
its center frequency is locked to a reference interferometer. The optimum phase-matching condition is achieved by
temperature-tuning the KNbO3 crystal. Tunable blue light between 426.8 nm and 433.6 nm is successfully
generated with the highest conversion efficiency of 31% for 470 mW pump power. It is found that the optimum
phase-matching temperature depends on the pump power as well as the pump wavelength resulting from the thermal effect.
Hybrid-Type InGaAlP/GaAs Distributed Bragg Reflectors for InGaAlP Light-Emitting Diodes
Authors: Sugawara Hideto , Kazuhiko Itaya Kazuhiko Itaya , Gen-ichi Hatakoshi Gen-ichi Hatakoshi
Published: October 2002

Hybrid-type distributed Bragg reflectors (DBRs) with InAlP/GaAs and InAlP/InGaAlP multilayers grown by
metalorganic chemical vapor deposition (MOCVD) have been investigated. The structure of the DBRs was designed using
a theoretical calculations considering the absorption loss and refractive index of each stacked layer. The wide-band,
high-reflectivity characteristics were also experimentally confirmed. Good electrical conductivity through InGaAlP
light-emitting diodes (LEDs) with the hybrid-type DBRs was obtained in spite of the many interface needed for the
multiple layers of the DBRs. A luminous intensity of 0.8 cd was obtained at 565.7 nm (nearly pure green light).
Well Width Dependence of Threshold Current Density in Tensile-Strained InGaAs/InGaAsP Quantum-Well Lasers
Authors: Yamamoto Tsuyoshi , Nobuhara Hiroyuki , Tanaka Kazuhiro , Inoue Tadao , Takuya Fujii Takuya Fujii , Kiyohide Wakao Kiyohide Wakao
Published: October 2002

We investigated how the well width affected threshold current density in tensile-strained InGaAs/InGaAsP quantum
well lasers. Lasers with wider wells had lower threshold current densities, independent of the cavity length. This is
mainly caused by the reduction of the transparent current density.
Raman Scattering of FexRu1-xS2Mixed Crystals
Authors: Hwang Song-Tzer , Lee Ming-Chih , Tsay Ming-Yih , Huang Ying-Sheng
Published: October 2002

Raman scattering of mixed dichalcogenides FexRu1-xS2has been measured for the first time. Our results show not only resonant enhancements that are related to the inter-electronic-band transitions, but also mixed mode behavior with strong coupling between neighboring Raman active modes. Good interpretation is obtained by the spatial correlation model.
Electrical Properties of (Pb, La)TiO3 Thin Films Fabricated by Multiple Cathode Sputtering
Authors: Maiwa Hiroshi , Ichinose Noboru , Kiyoshi Okazaki Kiyoshi Okazaki
Published: October 2002

(Pb, La)TiO3 (PLT, La/Ti=0.17) thin films were prepared by multiple cathode rf-magnetron sputtering.
The electrical properties of these films were investigated. The PLT thin films deposited on Pt/MgO substrates
exhibited higher crystallinity and better ferroelectric properties, compared to the films deposited on
Pt/SiO2/Si substrates. The hysteresis loops of the PLT films on RuO2/Ru/SiO2/Si or
RuO2/Ru/MgO were narrow compared to that of film deposited on platinum electrodes. The dielectric constant
of PLT films deposited at 540° C decreased with decreasing film thickness. Existence of a Pb-deficient
layer near the film/substrate interface was observed by X-ray photoemission spectroscopy (XPS) analysis. By lowering
the substrate temperature to 515° C, Pb re-evaporation from the substrate decreased, and ferroelectric
properties were improved. By controlling the Pb/Ti incident ratio, thin films with different Pb contents of the
interface layer were formed. With an increase in the Pb content near the film/substrate interface, the fatigue
resistance increased.
Three-Dimensional Simulation of Multi-Domain Homeotropic Liquid Crystal Cells
Authors: Shui-Chih Alan Lien Shui-Chih Alan Lien
Published: October 2002

We have carried out simulations of the three-dimensional (3-D) liquid director structures of multi-domain
homeotropic (MDH) liquid crystal (LC) cells. Based on the calculated 3-D LC director structures, the maximum pixel
averaged optical transmissions of the MDH liquid crystal cells have also been computed. Information regarding the 3-D
LC director structures and the maximum pixel averaged optical transmissions is used to evaluate the optical
performances of various pixel electrode structure for the MDH LC cells.
Effect of Polymer Network Made of Liquid Crystalline Diacrylate on Characteristics of Liquid Crystal Display Device
Authors: Hasebe Hiroshi , Takatsu Haruyoshi , Iimura Yasufumi , Kobayashi Shunsuke
Published: October 2002

We investigated the effect of the polymer network, which is made of a liquid crystalline diacrylate in a nematic
liquid crystalline host, on the alignment and motion of liquid crystals. We found that the polymer network has strong
influence on the alignment and motion of the liquid crystals even with the low concentration of 2 wt% of the liquid
crystalline diacrylate. The polymer network prepared in an electric field gives a uniform alignment of liquid crystals
with a tilt angle to the alignment layer because of good orientation of the polymer network. Furthermore, we report
the effect of the oriented polymer network on the characteristics of a twisted nematic (TN) device.
Effect of Processing on Removal of Hydroxyl Absorption Bands in Li2O–CaO–Al2O3–GeO2 Glass
Authors: Wang Moo-Chin , Wang Jenn-Shing , Hon Min-Hsiung
Published: October 2002

The various processes for removing hydroxyl (–OH) absorption bands of
Li2O–CaO–Al2O3–GeO2 (LCAG) glass and variables such as melting time,
temperature, pressure, additive agent and heat treatment have been studied. The absorption coefficient (B
OH)
increases with increasing melting pressure, but decreases with increasing melting time and temperature. With added
CaF2, the –OH group content in the glass may be decreased to B
OH=0.068 mm-1. Since the
test specimen is heat-treated at 630° C for 24 h, the O–H bond band shifts from 2.83 µ m to
2.99 µ m and bands at 3.37 µ m form due to the Ge–O bond.
Epitaxial Growth of Highly Crystalline and Conductive Nitride Films by Pulsed Laser Deposition
Authors: Lee Myung Bok , Kawasaki Masashi , Yoshimoto Mamoru , Kumagai Masao , Koinuma Hideomi
Published: October 2002

KrF pulsed excimer laser deposition was found to produce epitaxial TiN and ZrN films on Si{100} and MgO{100}
substrates, respectively, with optimized laser fluence, substrate temperature and nitrogen ambient pressure. The
epitaxial nature of these films was confirmed by the X-ray pole figure, and the crystallinity was evaluated from the
full width at half-maximum of the X-ray ω-rocking curve and Rutherford backscattering spectroscopy. The
electrical resistivities of these epitaxial TiN and ZrN films were as low as 40 µ Ω cm. The crystal
orientation and impurity phase formation are discussed based on a thermodynamic consideration.
Electron Affinity of Single-Crystalline Chemical-Vapor-Deposited Diamond Studied by Ultraviolet Synchrotron Radiation
Authors: Eimori Nobuhiro , Mori Yusuke , Hatta Akimitsu , Toshimichi Ito Toshimichi Ito , Akio Hiraki Akio Hiraki
Published: October 2002

We have investigated the electron affinity of (111) and (100) single crystalline surfaces of chemical-vapor-deposited diamond with additional treatments. For specimens exposed to hydrogen plasma (H treatment), the
electron affinities are found to be negative from photoyield spectra using ultraviolet synchrotron radiation light,
because the threshold energies of photoyield from these specimens are located at an energy of h ?< 5.5 eV, which
is the indirect band-gap energy of diamond. The threshold energies of photoyield from surfaces annealed in oxygen
atmosphere at 500?C are higher than those from H-treated surfaces. This can be explained in terms of an increase
of work function of the oxygen-adsorbed surfaces.
Analysis of Polyethyleneterephthalate Film Surface Sputtered with Ar Neutral and Ar Ion Beams
Authors: Iijima Yoshitoki , Sato Tetsuya , Hiraoka Kenzo
Published: October 2002

Polyethyleneterephthalate (PET) film surfaces sputtered with Ar neutral and Ar ion beams were investigated with
scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). It was
observed that the surface sputtered with the Ar neutral beam was flatter than that with the ion beam. AFM observation
showed that the morphology size on the surface sputtered with Ar neutral beam was larger than that made by ion beam
sputtering. XPS analysis showed that the decomposition of chemical bonding was reduced and the formation of amorphous
carbon on the surface was suppressed when the surface was sputtered with the Ar neutral beam. The flattening mechanism
could be clarified by AFM observation and XPS analysis. The sputtering process differs between the neutral beam and
the ion beam with the same energy and dose.
Energy Distribution of Thermally Stimulated Exoelectrons from MgO after Low-Energy Electron Bombardment
Authors: Ryoitiro Huzimura Ryoitiro Huzimura , Katsuko Nakahira Katsuko Nakahira
Published: October 2002

The energy distribution of thermally stimulated exoelectrons around 150° C from MgO(001) surfaces after bombardment at room temperature with electrons at incident energies (Ep) between 75 eV and 3 keV has been measured in ultrahigh vacuum using the retarding potential difference method. The differential distribution usually shows a single peak. Depending onEpand conditions of ambient gas adsorption, the retarding voltage which presents peak shifts from about 3 to 16 V and the width from about 3 to 10 eV. The charge distribution in surface regions with such width is discussed using the charge density distribution function proposed by Kortovet al..
Ion Impact Energy Distributions and Properties of Amorphous Hydrogenated Carbon Thin Films Deposited in a Self-Biased RF Discharge
Authors: Tatsuta Toshiaki , Tachibana Kunihide , Osamu Tsuji Osamu Tsuji
Published: October 2002

In a self-biased RF discharge in CH4 we have investigated the relationships between the properties of hydrogenated amorphous carbon (a-C:H) film and ion impact energy distributions (IIEDs) measured by retarding-type
ion energy analyzer at both parallel-plate electrodes. On the RF electrode a high-energy peak (HEP) dur to the
ion beam component was observed in IIED. The height of HEP decreased with increasing pressure at a given
self-bias voltage (V
dc) and the central energy of HEP increased linearly with V
dc at a given pressure. The micro
hardness of the film increased in proportion to the total incident ion current (TIIC) and central energy of HEP. The hydrogen content decreased and the surface morphology became fine as the central energy of HEP increased.
From Raman and IR absorption spectra it turned out that there was an optimal energy of HEP to increase the
content of the sp3 bonding structure in the film.
Loss Increase of (LuNdBi)3(FeAl)5O12 Films Caused by Sputter Etching
Authors: Yokoi Hideki , Mizumoto Tetsuya , Ida Takehiro , Kazuki Kozakai Kazuki Kozakai , Yoshiyuki Naito Yoshiyuki Naito
Published: October 2002

Rib waveguides, which are made of magnetic garnet films of composition (LuNdBi)3(FeAl)5O12 (LNB),
fabricated by Ar sputter etching have large propagation loss in comparison with LNB slab waveguides. X-ray
photoelectron spectroscopy (XPS) is used to investigate chemical states of constituent elements existing in the
surface layer where a Ti mask has been deposited during the etching process. The analysis shows that Fe chemical shift
due to Ar+ ion bombardment can cause increase in the optical absorption loss, and hence the propagation loss.
It is effective for suppressing the loss increase to employ a SiO2 mask deposited onto LNB film instead of
a Ti mask.
Theoretical Study of Latent Image Formation in Chemically Amplified Resists
Authors: Nakamura Jiro , Hiroshi Ban Hiroshi Ban , Akinobu Tanaka Akinobu Tanaka
Published: October 2002

Theoretical analysis of chemically amplified resists indicates that a higher reaction order of acid-catalyzed
reaction and lower diffusion length of acid enhance image quality. We identified the relation between diffusion length
and the number of catalytic acids appropriate for inducing a given amount of acid-catalyzed reactions as a function of
the difference between the activation energies of diffusion (E
ad) and
acid-catalyzed reaction (E
ar), and the post-exposure baking (PEB) temperature. When E
ad=E
ar,
the diffusion length required for a certain amount of acid-catalyzed reaction is inversely proportional to the square
root of the amount of generated acids, regardless of PEB temperature. When E
ad≠E
ar, the required
diffusion length depends on PEB temperature. When E
ad<E
ar, the diffusion length is smaller at higher
PEB temperatures, and this will be preferable for enhancing the resist resolution.
Development of Microwave Counter of Paper Sheets
Authors: Shigeru Nakayama Shigeru Nakayama
Published: October 2002

A simple method of noncontact measurement of the number of sheets of paper in a stack is developed by using
a homodyne interference method in a microwave Doppler module. The measurement of the number of sheets
is accurate up to 18 sheets for 84-?m-thick paper with a given moisture content, even if the moisture content
contained in the paper varies.
Noncontact Evaluation of Capacitance Disk Memory with Ferroelectric/Semiconductor Structure
Authors: Sanada Kazuo , Ryoichi Yamamoto Ryoichi Yamamoto , Shizuo Umemura Shizuo Umemura
Published: October 2002

Noncontact evaluation of capacitance disk memory with ferroelectric semiconductor (FS) structure was performed in order to avoid wear of the head and medium. Head-medium spacing was actively controlled using differential capacitance between the head and medium as the active feedback signal. Using this system, head-medium spacing could be stably controlled to be as low as 30 nm, which is less than that of a magnetic hard disk. Ferroelectric film of the medium was poled, which corresponded to recording in memory application, while head-medium spacing was kept constant using the active spacing control system. Change in capacitance due to poling direction, which corresponded to the reproduction signal in memory application, could be observed at the spacing below 100 nm. As a result, we confirmed that ferroelectric/semiconductor disk memory could function without head-medium contact. The surface image was also obtained using the capacitance signal while differential capacitance was kept constant.
Dynamic Properties of Protein and Water Studied Through Effects of Water Content on Water Relaxations in Erythrocytes
Authors: Masaaki Iino Masaaki Iino
Published: October 2002

Magnetizations of water protons in human erythrocytes were measured using an off-resonance irradiation technique
by varying the irradiation frequency and water content. The frequency dependences of the magnetizations were well
expressed by the rate equations, which gave the tumbling time of hemoglobin protons and the intrinsic relaxation rates
of water and hemoglobin protons. Analysis of the data determined the amounts and the average correlation times of
bound water fractions. The average lifetime of the bound water in the interior of the protein with respect to exchange
with the bulk water was found to be 1.0±0.3 µ s. The estimation
of the surface hydration layer showed excellent agreement with the amount measured by thermodynamical methods.
Formation Mechanism and Pore Size Control of Light-Emitting Porous Silicon
Authors: Seo Young Hun , Nahm Kee Suk , An Myung Hwan , Suh Eun-Kyung , Lee Young Hee , Lee Kee Bang , Lee Hyung Jae
Published: October 2002

The mechanisms of silicon dissolution and pore formation during the formation of
porous silicon layers (PSLs) are investigated in the HF-water electrolyte solution.
As HF concentration increases in the electrolyte, the depth of pores increases while
the pore diameter decreases. It is found that hydroxide ion ( OH-) plays an apparently
significant role in the reaction with silicon. The formation of silicon oxide is observed
on the silicon surface during PSL formation. The dissolution mechanism of silicon is
presented, based on spectroscopic analyses for the porous silicon surface. The area of
initially formed silicon oxide on the silicon wafer surface determines the pore diameter.
With increasing amount of OH- ions, or equivalently decreasing HF concentration,
the thickness of the silicon walls between pores is reduced, revealing the blue shift of
photoluminescence energy due to the quantum size effect.