bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-Type Doping Limits in ZnMgSSe and ZnSSe Compound Semiconductors
Authors: Kenkichi Hirano Kenkichi Hirano , Ikuo Suemune Ikuo Suemune , Go Sato Go Sato 
Published: October 2002

The p-type doping limit in ZnMgSSe was examined using an amphoteric native defect model. The results of measurements on p-type doping in ZnMgSSe were well reproduced with the band offset localized to the valence band in ZnSe/ZnMgSSe considering the growth temperature. This result is close to the one reported recently by Shahzad et al. [Appl. Phys. Lett. 67 (1995) 659], i.e., ΔE
v≈0.9ΔE
g. The results of measurements on p-type doping in ZnSSe were also well reproduced with the known band offset in ZnSe/ZnSSe. Although the doping efficiency is reduced for a larger energy gap in both material systems, the improvement of doping efficiency by increase of the growth temperature was predicted from the model.
Measurement of Azimuthal Anchoring Energy at Liquid Crystal/Photopolymer Interface
Authors: Li Xiang Tong , Pei Dong He , Kobayashi Shunsuke , Yasufumi Iimura Yasufumi Iimura 
Published: October 2002

The photopolymer material of poly(vinyl cinnamate) (PVCi) has been used to investigate the contribution of the anisotropic van der Waals force to the azimuthal anchoring energy in a pentyl cyanobiphenyl (5CB)/PVCi system. The optical anisotropy of a PVCi film is precisely controlled by varying the exposure time of linearly polarized UV light, and the azimuthal anchoring energy in the film is estimated by measuring the width of the Néel wall. The result shows that the azimuthal anchoring energy in the 5CB/PVCi system increases exponentially with increasing optical anisotropy, indicating the existence of additional contributions to the LC alignment.
Deep-Level Luminescence in Czochralski-Grown Silicon Crystals after Long-Term Annealing at 450°C
Authors: Shigeo Ibuka Shigeo Ibuka , Michio Tajima Michio Tajima , Hiroshi Takeno Hiroshi Takeno , Masatoshi Warashina Masatoshi Warashina , Takao Abe Takao Abe , Keigo Nagasaka Keigo Nagasaka 
Published: October 2002

Isothermal annealing at 450°C for more than 100 h was performed for Czochralski-grown silicon crystals. We detected a photoluminescence (PL) band at around 0.86 eV at room temperature. Temperature dependence of PL spectra indicates that the 0.86 eV band has an origin distinct from that of the 0.885 eV line observed at liquid helium temperature. Spectral shape analysis using the curve-fitting technique indicates that at least two different electronic levels are formed by oxygen precipitation during annealing. The peak energy position and half-width of the 0.86 eV band were different from those of a similar 0.86 eV band resulting from two-step annealing at 450°C and subsequently at 650°C. The difference in the spectral shape is ascribed to the structural change of oxygen aggregates. We believe that PL at room temperature is sensitive to the morphology of these aggregates.
The New Re-writable Disc system for Digital Versatile Disc
Authors: Muramatsu Eiji , Yamaguchi Atsushi , Horikawa Kunihiko , Kato Masahiro , Taniguchi Shoji , Jinno Satoshi , Yamaguchi Masataka , Kudo Hideo , Inoue Akiyoshi 
Published: October 2002

The authors have developed a new re-writable disc system named digital versatile disc (DVD)-RW. The basic concept of this system consists of the following characteristics.
1) This system has added a re-writable feature to the DVD-R (write once system).
2) It is compatible with DVD-ROM, DVD-Video and DVD-Audio systems.
By capitalizing on the characteristics of this system as much as possible, it will be possible to produce a useful standard, meeting the users' demand for video recording application of the DVD.
Charged Particle Emission and Luminescence upon Bending Fracture of Granite
Authors: Yoshizo Kawaguchi Yoshizo Kawaguchi 
Published: October 2002

Charged particle emission and luminescence upon bending
fracture of granite were investigated in a vacuum. In
most cases, sharp peaks of charged particle emission and
luminescence were observed at the very instant of final
fracture, and continued for several seconds. However, it
sometimes happened that the bending fracture needed about
10-20 ms, and a sharp peak of charged particle emission
was also observed at the beginning of the decrease in the
applied load, suggesting that initiation and propagation
of microcrack induced the charged particle emission. In
both cases, luminescence was observed only at the instant
of final fracture. Luminescence spectra were composed of
two bands centered at about 2.1 and 3.0 eV, and each band
showed different decay profiles, suggesting the contribution
of the different defect centers.
Superconducting YBa2Cu3O7-δ-Ag Thin Films (TC( 0) = 90 K) by Pulsed Laser Deposition on Polycrystalline Ba2NdNbO6; A Novel Substrate for YBa2Cu3O7-δFilms
Authors: M. John Jose Kurian , K. Sajith Poo , Koshy Jacob , P. Pai Subash , Richard Pinto Richard Pinto 
Published: October 2002

The development and characterisation of \ba, a novel ceramic substrate material for \yb superconductor, are reported. \ba has a complex cubic perovskite structure [\bb] with lattice constanta= 8.573Å. The dielectric properties of \ba are in a range suitable for its use as a substrate for microwave applications. \ba was found to have a thermal expansion coefficient of 8.6×10-6°C-1and a thermal conductivity of 87 W·m-1·K-1. Superconducting \yb-Ag thin films have been grownin situon polycrystalline \ba by pulsed laser ablation technique and the optimum conditions have been established. The films exhibited (00l) orientation of an orthorhombic \yb phase and gave a zero resistivity superconducting transition [TC(0)] at 90 K with a transition width of ∼1.5 K andJC∼3 ×105A/cm2at 77 K.
A New Structure of an N-Channel Junction Field-Effect Transistor Embedded in a Pin Diode for an X-Ray Detector
Authors: Hideharu Matsuura Hideharu Matsuura , Katsuhiko Nishida Katsuhiko Nishida 
Published: October 2002

A new structure of an n-channel junction field-effect transistor (n-channel JFET) embedded in a pin diode for an X-ray detector is proposed. When a p/n junction, which is formed on the n- substrate (i. e., i layer) of the pin diode around the JFET, is reverse-biased, the depletion region is extended under the n channel of the JFET, because the donor density of the n- substrate is as low as 2 ×1012 cm-3. This indicates that the n channel can be electrically separated from the n- substrate, without a p region under the n channel. Since it is unnecessary to form the p region under the n channel, only one type of donor exists in the n channel of the JFET proposed here, suggesting that this n-channel JFET has the advantage of high performance due to high mobility and a low noise characteristic due to low defect densities.
Liquid Phase Chemical-Enhanced Oxidation for GaAs Operated Near Room Temperature
Authors: Hwei-Heng Wang Hwei-Heng Wang , Chien-Jung Huang Chien-Jung Huang , Yeong-Her Wang Yeong-Her Wang , Mau-Phon Houng Mau-Phon Houng 
Published: October 2002

A new chemical enhanced oxidation method for gallium arsenide (GaAs) in liquid phase near room temperature (40°C–70°C) is proposed and investigated. Featureless oxide layers with good uniformity and reliability can be grown efficiently on GaAs without any extra energy source. A relatively high oxidation rate (≃1000 Å/h), about 50 times higher than that obtained during oxidation in boiling water has been realized. Based on the results of X-ray photoelectron spectroscopy (XPS), excellent chemical stability after thermal annealing as well as good chemical stoichiometry have been realized. The oxide was determined to be composed of Ga2O3 and As2O3.
High-Mobility Two-Dimensional Electron Gas in an Undoped Heterostructure: Mobility Enhancement after Illumination
Authors: Tadashi Saku Tadashi Saku , Koji Muraki Koji Muraki , Yoshiro Hirayama Yoshiro Hirayama 
Published: October 2002

High-mobility two-dimensional electron gas (2DEG) is formed at an undoped
GaAs/AlGaAs inverted heterointerface through the field-effect using a back-gate.
Despite the structure being undoped, mobility enhancement is observed
at 1.6 K after illumination. This suggests effective reduction
of background impurity scattering by illumination. The maximum mobility
reached after illumination, 5×106cm2/V·s,
is the highest value ever reported for gated undoped
heterostructures,
including both normal- and inverted-type structures.
This mobility is also the
highest ever
reported for inverted GaAs/AlGaAs heterostructures.
Enhanced Emission from Europium Complex Utilizing Quantum-Well Structure in Organic Electroluminescent Device
Authors: Hamada Yutaka Ohmori , Katsumi Yoshino Katsumi Yoshino 
Published: October 2002

Enhanced electroluminescence from europium (Eu) complex has been observed utilizing single, or multiple quantum–well structures consisting of a Eu complex well layer sandwiched between azomethin–zinc complex layers. Sharp emission at 614 nm has been observed from the Eu complex in the quantum-well structure. The thinner the well layer of the Eu complex, the stronger the emission intensity from it, under the same injection current. The mechanism of enhanced emission from the quantum-well structure has been discussed.
Preparation of Self-Assembled Mercaptoalkanoic Acid Multilayers on GaAs (110) Surfaces
Authors: Akio Nagahara Hirotaka Ohno , Wataru Mizutani Wataru Mizutani , Junkou Takagi Junkou Takagi , Hiroshi Tokumoto Hiroshi Tokumoto 
Published: October 2002

Mono- and double layer films have been formed by the self-assembly of
16-mercapto-hexadecanoic acid, (MHDA), HS(CH2)15COOH, via selective
ionic interaction. To understand the formation process in the nanometer length scale,
atomic force microscopy (AFM) studies have been conducted in combination with micro
X-ray photoelectron spectroscopy (µ-XPS), Auger electron spectroscopy (AES)
and micro-fourier transform infrared spectroscopy with the attenuated total
reflection method (µ-FTIR ATR). After the formation of a self-assembled
monolayer (SAM) was completed, the surface treated
with copper ions was immersed in a solution of MHDA. By this method,
an atomically
smooth double layer was successfully formed on cleaved GaAs (110) surfaces. The
formation speed of the second layer was faster than that of the SAM, indicating
stronger interaction of thiol functional groups with Cu2+ ions than with GaAs
surfaces.
Nonelectrical Poling in Ferroelectric Polycyanophenylenesulfides
Authors: Ide Junya , Tasaka Shigeru , Inagaki Norihiro 
Published: October 2002

A new poling method utilizing the cooperativity of cyanophenyl groups
was proposed in ferroelectric polycyanophenylenesulfides (PCPS). The method
called “surface energy poling” takes advantage of the energy difference in
the top and bottom surfaces of a polar aggregate to form a remanent
polarization. The PCPS film sandwiched between a metal with higher surface
energy and polytetrafluoroethylene with lower surface energy was heated to
T
cp [1.2×T
g (glass transition temperature)] and cooled slowly to room
temperature. The remanent polarization that gives a pyroelectric constant of
10 µC/m2 K and an electrooptic coefficient (r
33) of 80 pm/V in the
resulting film was realized.
Diamond Deposition and Behavior of Atomic Carbon Species in a Low-Pressure Inductively Coupled Plasma
Authors: Teii Haruhiko Ito , Masayuki Ishikawa Masayuki Ishikawa , Masafumi Ito Masafumi Ito , Masaru Hori Masaru Hori , Takashi Takeo Takashi Takeo , Terumasa Kato Terumasa Kato , Toshio Goto Toshio Goto 
Published: October 2002

Diamond was successfully synthesized by using
H2-rich CH4/CO/H2 and H2-rich CH4/H2
inductively coupled plasmas at a pressure of 11 Pa.
The ratio of particle size to deposition time, as a criterion
of the diamond growth rate, in
H2-rich CH4/CO/H2 mixture gas plasmas was higher than that in
H2-rich CH4/H2 mixture gas plasmas.
The deposits in H2-rich CH4/H2 and
H2-rich CH4/CO/H2
mixture gas plasmas were found to contain nondiamond phases,
as confirmed by Raman spectroscopy.
In order to investigate the mechanism involved in diamond
formation, C-atom densities in the plasmas were measured
by vacuum ultraviolet absorption spectroscopy
with a carbon hollow cathode lamp.
In addition, CH, OH and H-atom
emission intensities were measured by optical emission
spectroscopy.
As a result, it was found that
the C-atom densities increased considerably with
increasing mixture ratio of CO to CH4.
On the basis of the correlation between the quality
of deposits and the C-atom densities,
C-atoms were determined to probably contribute to the formation of
nondiamond phases in the deposits.
Enhanced THz Radiation from Femtosecond Laser Pulse Irradiated InAs Clean Surface
Authors: Hideyuki Ohtake Hideyuki Ohtake , Shingo Ono Shingo Ono , Zhenlin Liu Zhenlin Liu , Nobuhiko Sarukura Nobuhiko Sarukura , Michiharu Ohta Michiharu Ohta , Kazuya Watanabe Kazuya Watanabe , Yoshiyasu Matsumoto Yoshiyasu Matsumoto 
Published: October 2002

A significant enhancement of THz radiation from an InAs clean (100) surface is observed with irradiation of femtosecond laser pulses at 50 K. Due to the surface cleaning and cooling temperature, the THz-radiation intensity from the InAs clean (100) surface at 50 K becomes to 10 times larger than that from an uncleaned surface at room temperature.
Intense-Heavy-Ion-Beam Transport through an Insulator Beam Guide
Authors: Takashi Kikuchi Takashi Kikuchi , Shigeo Kawata Shigeo Kawata , Shigeru Kato Shigeru Kato , Susumu Hanamori Susumu Hanamori , Masaru Yazawa Masaru Yazawa 
Published: October 2002

In this study, we investigate an intense-heavy-ion-beam transport through an insulator beam guide by numerical simulation. In our previous papers [Jpn. J. Appl. Phys. 35 (1996) L1127, Jpn. J. Appl. Phys. 37 (1998) L471], we proposed a new system for electron and proton beam transport using an insulator beam guide. We apply this system to a singly charged cesium (Cs+) ion beam transport. An intense Cs+ ion beam generates a plasma on the insulator surface. Electrons are extracted from the plasma, and the beam charge is effectively neutralized by the electrons. Electron extraction is self-regulated by the net space charge of the beam. Consequently, an intense Cs+ ion beam can be efficiently transported by the proposed system.
Efficient CW Operation of TEM00 Mode from a Diffusive Reflector-Type Diode-Side Pumped Nd:YAG Laser
Authors: Jongmin Lee Jongmin Lee , Hee-Jong Moon Hee-Jong Moon , Jonghoon Yi Jonghoon Yi , Byungheon Cha Byungheon Cha 
Published: October 2002

We fabricated a diode side-pumped Nd:YAG laser by using a diffusive
reflector.
In the reflector, 3-fold narrow rectangular slits were made in order to
transfer diode pump power directly
into the diffusive cavity. In a linear short cavity, 190 W multimode
output power
was obtained with the optical efficiency of 43%.
We investigated the characteristics of low mode operation with a linear
dynamically stable resonator.
60 W CW TEM00 output power was obtained when the pump power was
300 W, which corresponds to
the optical efficiency of 20%.
A Digital-to-Analog Converter of Displacement by an Integrated Micromechanism
Authors: Hiroshi Toshiyoshi Hiroshi Toshiyoshi , Dai Kobayashi Dai Kobayashi , Makoto Mita Makoto Mita , Gen Hashiguchi Gen Hashiguchi , Hiroyuki Fujita Hiroyuki Fujita , Junji Endo Junji Endo , Yasuo Wada Yasuo Wada 
Published: October 2002

We have newly invented a micromechanism for precise position
control, which is equivalent to that of an electrical
digital-to-analog converter(DAC) of the R-2R resistor network.
The micromechanical C-2C compliance suspension network has been
fabricated on a silicon-on-insulator wafer by a micromachining
technique. When N-bit digital driving voltages are applied to
the micromechanism, cascaded electrostatic microactuators produce
a set of displacements of ±1 µm. These displacements
accumulate in the suspension network with binary weights to
synthesize DAC-like displacement output. A traveling displacement
of 6 µm is obtained while the positioning resolution is
0.38 µm in the case of 4 bit input. Resolution can be
improved further by increasing the addressing size of the input.
Photostimulated Luminescence of CuCl Quantum Dots in NaCl Crystals
Authors: Yasuaki Masumoto Yasuaki Masumoto , Seitaro Ogasawara Seitaro Ogasawara 
Published: October 2002

Photostimulated luminescence (PSL) was observed in CuCl quantum dots embedded in NaCl crystals at low temperatures of up to 120 K. This observation demonstrates that the quantum dot system is a new class of PSL materials. The thermal quenching, spontaneous decay and excitation-fluence dependence of the PSL are almost the same as those of persistent spectral hole burning (PSHB), indicating that the photoionization of quantum dots and the subsequent carrier capture at the traps near the quantum dots bring forth both PSL and PSHB. The traps form a Gaussian band and are considered to arise from Cu+ in NaCl. The requirement for the new class of PSL materials is the presence of quantum dots and nearby carrier traps in the host materials.
Photoluminescence and Electroluminescence from Polymer-Like Organic Thin Films Deposited by Plasma-Enhanced Chemical Vapor Deposition Using Para-Xylene as Precursor
Authors: Woo Park Donggeun Jung , Yongkeun Son Yongkeun Son 
Published: October 2002

Photoluminescence (PL) and electroluminescence (EL) were observed from the polymer-like organic
thin films (POTFs) deposited by plasma-enhanced chemical vapor deposition (PECVD) using p-xylene as
the precursor. Absorption and PL spectra suggested that the film includes visible-light-luminescing species.
The PL spectrum had a peak around 460 nm. Current-voltage (I-V) and luminescence-voltage (L-V) were
measured from the aluminum/POTF/indium-tin-oxide light-emitting diode (LED). L-V curve follows the I-V curve
showing a turn-on voltage of ∼ 2.5 V. The EL spectrum from the LED was similar to the PL spectrum.
Low-resistance InGa(Al)As Tunnel Junctions for Long Wavelength Vertical-cavity Surface-emitting Lasers
Authors: Markus Ortsiefer Markus Ortsiefer , Robert Shau Robert Shau , Gerhard Böhm Gerhard Böhm , Fabian Köhler Fabian Köhler , Gerhard Abstreiter Gerhard Abstreiter , Markus-Christian Amann Markus-Christian Amann 
Published: October 2002

A new method is proposed for a significant reduction of series resistance and device heating in long wavelength vertical-cavity surface-emitting lasers (VCSELs) based on InP. Our technique involves a twofold epitaxial growth with a buried low-resistance (3×10-6 Ωcm2) tunnel junction. The substitution of high-resistive p-type confining layers by low-resistive n-type material results in total resistances smaller 100 Ω even for the case of non-conducting dielectric mirrors. With the application of buried tunnel junctions in a VCSEL-structure, we could demonstrate small electrical series resistance (U < 1 V at 3 kAcm-2) and effective current confinement simultaneously. Furthermore, because of the laterally varying cavity length, an effective lateral waveguiding effect occurs.
Stranski-Krastanov Growth of Al on Ag Layers during Molecular Beam Epitaxy of (111) Al/Ag Superlattices
Authors: Toshiki Kingetsu Toshiki Kingetsu , Yasuhiro Kamada Yasuhiro Kamada , Masahiko Yamamoto Masahiko Yamamoto 
Published: October 2002

We studied the growth behavior of (111) Al/Ag superlattices during molecular beam epitaxy, using in situ reflection high-energy electron and ex situ X-ray diffractions. Epitaxial growth proceeded with an orientational relationship of Al(111)[110] ∥Ag(111)[110]. Although the first Al layer with 3-monolayer (ML) thickness grown on a Ag buffer layer did not show island growth, the second and succeeding (111) Al layers with 3-ML thickness were found to grow on Ag underlayers in the Stranski-Krastanov mode, in contrast to the layer growth of (001) Al/Ag superlattices reported previously. The critical Stranski-Krastanov thickness was seemingly 2 ML, and three-dimensional islands emerged upon further growth. Thus, superlattices with 3-ML-thick Al layers showed rough Al/Ag interfaces due to the presence of Al islands, while superlattices with 2-ML-thick Al layers exhibited rather flat interfaces. The strain relief of Al upon the formation of islands was detected. We discussed the possible cause of the difference in growth behavior between the (111) and (001) superlattices.
Electrochemical Formation of Uniform and Straight Nano-Pore Arrays on (001) InP Surfaces and Their Photoluminescence Characterizations
Authors: Fujikura Hajime , Liu Aimin , Hamamatsu Akihito , Sato Taketomo , Hasegawa Hideki 
Published: October 2002

Recently, <001>-oriented nanometer-sized pores (nano-pores) without side branches, unlike porous Si, have been realized by our group on (001) n-InP surfaces by means of electrochemical anodization in 1M HCl solution. However, they exhibit large structural nonuniformity including the presence of an irregular top layer, random pore positioning and wavy pore walls. In this study, attempts have been made to improve pore uniformity and to clarify their optical properties. Anodization in 1 M HCl+HNO3 solution realized highly uniform nano-pore arrays consisting of square-shaped straight pores defined by four crystalline (011) facets. This improvement is explained in terms of preferential etching along the vertical <001>-direction at the pore tip due to the slow etching rate along the lateral <011>-direction as well as the uniform supply of reactant species to pore tips realized by the removal of the irregular top layer during the anodization process. The nano-pore arrays show strong blue- and red-shifted photoluminescence emissions at high and low temperatures, respectively. These are assigned as emissions due to the transition between electron and hole quantum states inside the pore walls and that involving a broad surface state continuum at pore wall surfaces, respectively.
Molecular Beam Time of Flight Analysis of the Reaction Dynamics of Alkane Molecules Interacting with a Pt(111) Surface
Authors: Hiraoka Tomomi , Yagyu Sinjiro , Kondo Takahiro , Ikeuchi Toshiyuki , Yamamoto Shigehiko 
Published: October 2002

Molecular beam time-of-flight analysis has been applied to investigate the
reaction dynamics of hyperthermal alkane molecules such as methane and ethane
interacting with a Pt(111) surface. Below the threshold incident kinetic energy and
surface temperature, where direct inelastic collision is dominant, the velocity
distributions of scattered methane and ethane molecules qualitatively agree with the
prediction based on the classical cube model [R. M. Logan and R. E. Stickney:
J. Chem. Phys. 44 (1966) 195.]. Rotational mode excitation is found to be
much more significant in the case of ethane molecules than methane molecules. Once
dissociation occurs, however, reaction products roughen the surface and reduce the
effective mass of the surface, which makes the model no longer applicable. The
deviation from the prediction can be understood as a result of increased tangential
energy transfer and the multiple collision of incident molecules at the interacting
surface.
Surface Tension Variation of Molten Silicon Measured by Ring Tensiometry Technique and Related Temperature and Impurity Dependence
Authors: Hideo Nakanishi Hideo Nakanishi , Kenichi Nakazato Kenichi Nakazato , Kazutaka Terashima Kazutaka Terashima 
Published: October 2002

The surface tension of non doped, gallium-doped and boron-doped silicon melts has been measured as a function of temperature in purified argon atmosphere (oxygen partial pressure was less than 10-8 MPa) using the ring tensiometry technique. In all cases, the surface tension decreases linearly with increasing temperature. The surface tensions of γ={763-0.219×(T-T
m)}×10-3 N/m in the non doped silicon melt, γ={777-0.243×(T-T
m)}×10-3 N/m in the gallium-doped silicon melt and γ={721-0.098×(T-T
m)}×10-3 N/m in the boron-doped silicon melt were obtained. We have found that the surface tension of the silicon melt depends on the species of impurity. However, the surface tension anomaly near the solidification point previously reported by Sasaki et al. [1] was not observed under any experimental conditions.