bluuebunny/crossref_metadata_2025 huggingface dataset:
Narrow-Linewidth InGaAsP/InP Metal-Clad Ridge-Waveguide Distributed Feedback Lasers
Authors: Wolf T. , Borchert B. , K. Drögemüller K. Drögemüller , M.-C. Amann M.-C. Amann
Published: February 2005

InGaAsP/InP metal-clad ridge-waveguide distributed feedback lasers with an improved device structure were made by single-step liquid-phase epitaxy. With -20 nm detuned Bragg wavelength, χL around 1-2 and 0.08-0.1 µm active layer thickness the linewidth of 400-800 µm long as-cleaved lasers is as small as 2 MHz at 10-15 mW optical power.
Perception of 3-D Illusory Surface with Binocular Viewing
Authors: Masanori Idesawa Masanori Idesawa
Published: February 2005

A new discovery was made concerning the illusion of 3-D surface perception in binocular fusion. From the visual stimuli of disparity given only partially along the contour of an object, the human visual system can perceive the 3-D surface (not only planar but also curved) where there are no visual stimuli to provide any depth information. There are several new findings concerning this illusion: the interaction between several illusory surfaces can be observed; an edge line can be perceived as an intersection of two illusory surfaces; the occluding effect between two illusory surfaces can be recognized; the transparent effect of the illusory surface can be seen with an adequate visual stimulus. These newly found illusory phenomena have close relations with the visual functions of 3-D space perception.
Asymmetric Distribution of Oxygen Precipitates in Czochralski Silicon Wafers Covered on the Backside with Polycrystalline Silicon Films
Authors: Hideki Yamanaka Hideki Yamanaka , Yoshihira Aoki Yoshihira Aoki
Published: February 2005

Preannealing in an oxidizing atmosphere only for 10 min and the existence of backside-polycrystalline silicon films during this preannealing are necessary and sufficient to form an asymmetric distribution of oxygen precipitates in the wafer interior. More silicon self-interstitials due to the oxidation migrate into a wafer interior from a front surface than from a back surface, because the backside film prevents silicon self-interstitials from migrating into the wafer interior. Correspondingly, more precipitation nuclei shrink near the front surface than near the back surface.
Very-Low-Temperature Preparation of Poly-Si Films by Plasma Chemical Vapor Deposition Using SiF4/SiH4/H2 Gases
Authors: Mohri Mikio , Kakinuma Hiroaki , Masaaki Sakamoto Masaaki Sakamoto , Hideo Sawai Hideo Sawai
Published: February 2005

Polycrystalline-Si (poly-Si) films have been prepared on glass substrates (Corning 7059) at a very low temperature (300°C) by conventional plasma chemical vapor deposition (plasma CVD) using SiF4/SiH4/H2 gases. The crystallinity was characterized by X-ray diffraction, reflection high-energy electron diffraction (RHEED), transmission electron microscopy (TEM) and Raman spectroscopy measurements. The effect of the SiH4 flow rate on crystallization proved to be large. The films indicated a strong <110>-preferred orientation. The crystalline fraction was estimated to be more than 80%. The average and maximum grain sizes were estimated to be 60 nm and 130 nm, respectively.
Superconducting YBa2Cu3O7-δ Particles Prepared from Freeze-Dried Nitrates
Authors: Kimura Yoshitaka , Ito Toshimichi , Hiroaki Yoshikawa Hiroaki Yoshikawa , Akio Hiraki Akio Hiraki
Published: February 2005

Homogeneous Y-Ba-Cu nitrate powders have been successfully fabricated by a freeze-drying method. Thermal decomposition of them resulted in fine superconducting YBa2Cu3O7-δ powders which were characterized by thermal analysis, SEM observation, X-ray diffraction and dc-magnetization. Results show that a rapid heating of the nitrate powders is required to obtain superconducting material of a good quality without segregation during their transitional liquid phases. In the process used, spherical YBa2Cu3O7-δ with diameters of 20-30 µm can be obtained. These results are compared to results in the case of carbonate.
Synthesis of Y-Ba-Cu-O Ultrafine Powders by Spray Drying and Subsequent Calcination under Low Pressure
Authors: Awano Masanobu , Kani Keiko , Yasumasa Takao Yasumasa Takao , Hiroyoshi Takagi Hiroyoshi Takagi
Published: February 2005

The calcination of homogeneous precursor powder of a Y-Ba-Cu-O superconductor derived from a spray drying and low-pressure calcining method led us to obtain fine homogeneous particles with a particle size of about 0.08 µm. The factors of minimization of the particle size were uniformity of the precursor powder and avoidance of increasing BaCO3. Sintered bodies obtained by sintering at relatively lower temperatures showed the texture with sub-micron size.
Synthesis, Crystal Structure and Magnetic Properties of Ba2Cu2WYO8.5-δ
Authors: Kitahama Katsuki , Hori Yoichi , Tomoji Kawai Tomoji Kawai , Shichio Kawai Shichio Kawai
Published: February 2005

Polycrystalline Ba2Cu2WYO8.5-δ has been synthesized by calcination at 1160°C. It crystallizes in the cubic system with the space group F43̄m, a=8.345 Å and Z=8/3. The structure consists of a superstructure of the perovskite type, whose three main axes are doubled. Thus, the structure is well illustrated if the formula is written as [ACuO3-ε][A(W2/3Cu1/3)O3-ε] with A=Ba or (Y2/3Ba1/3) and 1/6<ε<1/2. The existence of Cu+ was confirmed from the measurement of magnetic susceptibility. Unlike YBa2Cu3O6.5+δ, the substance exhibits no superconductive behavior even after 12 hours of heat treatment in O2 at 450°C.
Preparation of Ca-Substituted Y-Ba-Cu-O “124” Phase Thin Films by Magnetron Sputtering and Their Thermal Stability
Authors: Terashima Yoshiaki , Masayuki Sagoi Masayuki Sagoi , Tadao Miura Tadao Miura
Published: February 2005

Calcium-substituted Y-Ba-Cu-O “124” nearly single-phase thin films were prepared by sputtering at 550°C and annealing in oxygen at 750°C for 50 hours. T
c(on) and T
c(zero) values were 87 K and 65 K, respectively. At higher deposition temperatures, the as-grown “123” phase was not completely transformed into the “124” phase. The Ca-substituted “124” phase thin films were stable, and T
c(on) did not change below 600°C, even in pure nitrogen. However, at over 600°C, in nitrogen the films changed to the “123” phase and oxygen defects in the resultant “123” phase increased, and the T
c value dropped.
A Simple Method for the Preparation of YBa2Cu3Ox Superconducting Wires and Tapes Using Common Polymers
Authors: Bose Keya , Som Kamal K. , Pradip K. Dey Pradip K. Dey , Bijay K. Chaudhuri Bijay K. Chaudhuri
Published: February 2005

Wires and tapes of YBa2Cu3O
x
(Y-123) type high temperature superconducting oxides (HITSO) have been prepared by annealing the (Y-123)-polymer (polyethylene or polymethyl methacrylate) composites at (500-800°C) for eight hours. The (HITSO) wires and tapes of different porosity thus obtained are characterized from the studies of electrical and magnetic properties. Increase of porosity has little effect on the superconducting transition temperature. Importance of these composites for making non-porous (HITSO) wires or tapes has also been discussed.
Formation of the High-Tc Phase in Pb-Free Bi-Sr-Ca-Cu-O Thin Film
Authors: Nagai Satoshi , Fujimura Norifumi , Shiraishi Taichiro Ito
Published: February 2005

Amorphous films were annealed for 2 hours at 865°C to produce the high-T
c phase in a Pb-free Bi-Sr-Ca-Cu-O system, and the quality of the superconducting film was evaluated with X-ray diffraction. The amount of the high-T
c phase was large in the films deposited without heating as compared with the film deposited on a substrate heated at 300°C. The amount in the film deposited at 300°C increased by irradiation with 200 keV neon-ion to 1×1013 cm-2 before the annealing. The high-T
c phase could not be observed in the sample containing a low-T
c phase before the final annealing. The results indicated that the high-T
c phase formed directly from substantially amorphous films.
High Resolution Electron Microscopic Observation of Ferromagnetic Amorphous Ferrites in CaO-Bi2O3-Fe2O3 and Li2O-Bi2O3-Fe2O3 Systems
Authors: Nakamura Shin , Hirotsu Yoshihiko , Ichinose Noboru
Published: February 2005

High resolution electron microscopic (HREM) observation was carried out for the ferromagnetic amorphous ferrites in the CaO-Bi2O3-Fe2O3 and Li2O-Bi2O3-Fe2O3 systems. Although diffuse halo patterns were taken in electron diffraction, the HREM images revealed that microcrystalline domains extending to several nanometers were densely formed in these specimens. The result is consistent with our previous studies by static magnetic measurements and 57Fe Mössbauer spectra analysis. “Magnetic two phase model” that consists of a disordered speromagnetic phase and a microcrystalline ferrimagnetic phase is proposed for the ferromagnetic amorphous ferrites.
Nanometer-Sized Crystals Formed by the Mechanical Alloying in the Ag-Fe System
Authors: Kuyama Junji , Inui Haruyuki , Imaoka Susumu , Nasu Saburo , Keiichi N. Ishihara Keiichi N. Ishihara , Paul Hideo Shingu Paul Hideo Shingu
Published: February 2005

Mechanical alloying of a mixture of Ag and Fe powders, with initial grain size of about 100 µm, has been performed. Metallography in atomic scale, by the use of a high resolution electron microscopy, reveals the nanometer-sized crystalline structure in a Ag-50 at%Fe alloy. The 57Fe Mössbauer spectroscopy confirms the formation of small mutual solid solution in Ag and Fe phases.
Effects of Crystallinity of Hole Transport Layers on Organic Electroluminescent Device Performance
Authors: Hisashi Masui Hisashi Masui , Manabu Takeuchi Manabu Takeuchi
Published: February 2005

The electrical and light-emitting behavior of organic electroluminescent (EL) cells consisting of an 8-hydroxyquinoline aluminum light-emitting layer and a copper phthalocyanine hole transport layer has been studied. Both layers were prepared by vacuum deposition. When the indium-tin-oxide (ITO) glass substrate was cooled to near the liquid N2 temperature during the vacuum deposition of copper phthalocyanine, an amorphous layer was obtained, and the brightness of the cell was increased. It was confirmed that the light emission from the cell with an amorphous copper phthalocyanine layer was more uniform.
New MOS-Type Glucose Sensor Using Sputtered LaF3 Film
Authors: Katsube Teruaki , Kubota Tomoki , Shimizu Masaaki , Matayoshi Naoko , Miura Norio , Yamazoe Noboru
Published: February 2005

A MOS-type micro glucose sensor using a sputtered LaF3 (solid electrolyte) film was newly developed. The sensor, having a structure of GOD (glucose oxidase) immobilized film/Pt/LaF3/SiO2/Si/Al multiple layers, needs no external reference electrode. A stable response was obtained in the glucose concentration range from 2×10-4 to 2×10-2 M in a phosphate buffer solution of (pH 6.9), with a 90% response time of ca. 1 min. This MOS-type sensor was found to also respond to H2O2 in the buffer.
Observation of a Hole Trap in Liquid-Phase Epitaxial GaAsby Intentional Doping and Space-Charge-Limited Current Analysis
Authors: Ohsawa Jun , Lee Phang-Zong , Wieder Harry H. , Masatoshi Migitaka Masatoshi Migitaka
Published: February 2005

The hole trap at E
t-E
v=0.4 eV, typical of liquid phase epitaxial materials, has been detected by combining intentional doping of iron with the analysis of space-charge-limited current (SCLC) in the resulting high-resistivity GaAs. Diffusion of iron from a liquid spin-on source is employed to render undoped n--type liquid phase epitaxy (LPE) layers π-type, shifting its Fermi energy just above the E
t. The depth and density of the trap agree well with the reported values of a deep level transient spectroscopy (DLTS) measurement. Temperature dependence of the trap depth has also been obtained.
Spontaneous Emission and the Concept of Effective Area in a Very Short Optical Cavity with Plane-Parallel Dielectric Mirrors
Authors: Kikuo Ujihara Kikuo Ujihara
Published: February 2005

Spontaneous emission in a model cavity with very short length and with plane-parallel dielectric mirrors is calculated quantum-mechanically under perturbation approximation. Outgoing modes as well as guided modes are considered. Results on the directivity and the rate of emission into outer space are compared with the estimate by Purcell's method. This leads to the concept of “effective area” of the “cavity mode”, which has a simpie physical interpretation.
Electron Detachment from Negative Ions of SF6 in Xenon and Methane
Authors: Hartmut Hilmert Hartmut Hilmert , Werner F. Schmidt Werner F. Schmidt
Published: February 2005

The coefficient for electron detachment from negative SF6 ions in xenon and methane was measured as a function of E/N. Photo electrons were injected into mixtures of Xe/1%SF6 and CH4/1%SF6 where attachment led to the formation of negative ions. A novel field impulse method was employed for the detection and measurement of the detachment process.
Method to Generate a Large Number of Slow Positrons with a Modular Photon-Positron Converter
Authors: Mohri Akihiro , Michishita Toshinori , Tetsumori Yuyama Tetsumori Yuyama , Hitoshi Tanaka Hitoshi Tanaka
Published: February 2005

A simple method of producing an intense beam of slow positrons is proposed. X-rays radiating forward from a high Z target at the bombardment of pulsed e-beams penetrate many thin tungsten foil strips which are aligned parallel and assembled into a stack of modules with grids on one side. Stepwise electric potentials applied between the neighbouring modules produce the grid focussing field for collecting slow positrons emerging from the strip surfaces. The total wide surface area and the effective collection realize a high production rate of slow positrons above 1014 s-1 during the pulse of a 35 MeV, 0.5 A LINAC.
Exciton-Transition Energies and Band Structure of (GaP)n(GaAs)n/GaAs Atomic-Layer Superlattices
Authors: Tsugunori Takanohashi Tsugunori Takanohashi , Masashi Ozeki Masashi Ozeki
Published: February 2005

We studied exciton transitions and the band structure of (GaP)
n
(GaAs)
n
/GaAs [001] superlattices for n=1-4, using reflectance and photoluminescence spectral measurements. The exciton-transition energy showed a prominent drop for n=1 by 90 meV for n=2-4. This was attributable to the intensified delocalization of Γ electrons in the GaAs well by tunneling through the extremely thin GaP barrier layers. The transition was defined as direct for n=1, but indirect for n=2-4 by comparing the energies of exciton absorption and photoluminescence emission from the lowest excited state.
Direct Observation of 18O Tracer Diffusion in a YBa2Cu3Oy Single Crystal by Secondary Ion Mass Spectrometry
Authors: Tsukui Shigeki , Yamamoto Takao , Adachi Motoaki , Shono Yoshihiko , Kawabata Keisuke , Fukuoka Nobuo , Nakanishi Shigemitsu , Yanase Akira , Yoshioka Yoshiaki
Published: February 2005

Direct observation of 18O tracer diffusion by secondary ion mass spectrometry (SIMS) was made on a single crystal of YBa2Cu3O
y
with an array of steps on the stairlike surface. The unique distribution of the diffused 18O in the ab-plane and in the c-axis direction was shown visually as a mapped image, which revealed some fundamental processes on the oxygen penetration through the surface and diffusion in the inner crystal. It was found that at 530°C, the diffusion coefficient in an ab-plane is larger than that in a c-axis direction by more than five orders of magnitude.
Crystal Structure and Madelung Potential in R2-xCexCuO4-δ (R=Pr, Nd, Sm, Eu and Gd) System
Authors: Uzumaki Takuya , Nobuo Kamehara Nobuo Kamehara , Koichi Niwa Koichi Niwa
Published: February 2005

Powder X-ray diffraction measurements were taken in the R2-x
Ce
x
CuO4-δ (R=Pr, Nd, Sm, Eu and Gd) system. Rietveld refinement of these structures was performed assuming that the space group was 14/mmm. The lattice constant and rare earth metal location were determined to study the electrostatic effects of T'-phase materials. We found that the difference in the Madelung site potential, ΔV (V
R-V
Cu), as well as T
c has a peak for the Cu-O bond length. These data suggest that the carrier concentration is not constant in T'-phase materials and that changes in the carrier concentration influence T
c in these materials.
Anisotropic Conductivity and Its Anomalies in La8-xSrxCu8O20 Single Crystals
Authors: Takao Watanabe Takao Watanabe , Azusa Matsuda Azusa Matsuda
Published: February 2005

Single crystals of La8-x
Sr
x
Cu8O20 (1.0≤x≤1.8) are grown using the CuO flux method in a flowing O2 atmosphere. Resistivities parallel to the c-axis, ρ//c
, and perpendicular to the c-axis, ρ⊥c
, each show an anomaly around 140 K. The anisotropy ρ⊥c
/ρ//c
increases from 5∼10 at room temperature to 8∼20 at 5 K. These La8-x
Sr
x
Cu8O20 crystals can be considered quasi-one-dimensional conductors. Magnetic susceptibilities for both H//c and H⊥c show a cusplike anomaly around 140 K, suggesting the occurrence of a magnetic phase transition.
Properties of Bi-Pb-Sr-Ca-Cu-O Glass-Ceramic Fibers Formed by Glass-Drawing Method
Authors: Onishi Masashi , Michihisa Kyoto Michihisa Kyoto , Minoru Watanabe Minoru Watanabe
Published: February 2005

Flexible Bi-Pb-Sr-Ca-Cu-O glass fibers were prepared by the glass-drawing method. They showed superconducting properties after crystallization by heat treatment. The T
c and J
c values of the fibers were very sensitive to starting compositions and heat treatment conditions. The fiber with the starting composition of Bi2.1Pb0.9Sr2Ca2Cu3O
y
showed superconductivity with a J
c=1480 A/cm2 (77 K, zero magnetic field).
Kinetics of Laser-Assisted Chemical Vapor Deposition of Tungsten Microstructures
Authors: Auvert Geoffroy , Pauleau Yves , Tonneau Didier
Published: February 2005

Tungsten microstructures (dots, strips and films) have been deposited via H2 reduction of WF6 on polycrystalline silicon-coated quartz substrates irradiated with a focused cw argon laser beam. The deposition rate of W dots, deduced from α-step measurements of the height of dots, was investigated as a function of irradiation time, composition of H2-WF6 gas mixtures and laser-induced surface temperature. At a laser-induced surface temperature ranging from 340° to 670°C with an H2 partial pressure varying from 50 to 700 Torr, the reaction order with respect to H2 was equal to one-half, whereas at higher temperatures (750°-950°C) and lower H2 partial pressures (20-80 Torr), the reaction order with respect to H2 was found to be one. The reaction mechanism of the H2 reduction of WF6 on substrates irradiated with the argon laser beam is discussed.
Enlargement of Kinetic Inductance of NbN Superconducting Thin Films for Device Applications
Authors: Hossain Mohammad Sajjad , Yoshida Keiji , Kudo Keisuke , Keiji Enpuku Keiji Enpuku , Kaoru Yamafuji Kaoru Yamafuji
Published: February 2005

Experimental studies to enlarge kinetic inductance of NbN thin films using the effects of quality and thickness of the film are made by measuring Fiske current steps in the current-voltage (I-V) characteristics of NbN/Pb-In Josephson junctions. Experiments demonstrate that the specific kinetic inductance L
K can be enlarged over a wide range by changing stoichiometry of the film, as well as by making the film thickness thin, and that this enlargement becomes larger by both effects when the film thickness is in an ultra thin regime. This inductance is shown to be well fitted to L
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Three-Dimensional Analysis of Locally Implanted Atoms by MeV Helium Ion Microprobe
Authors: Kinomura Atsushi , Takai Mikio , Chayahara Akiyoshi , Fujii Kanenaga , Satou Mamoru , Susumu Namba Susumu Namba
Published: February 2005

Three-dimensional analysis by microprobe Rutherford backscattering (RBS) was used to nondestructively investigate inner-layer distributions of locally implanted atoms. Nickel-implanted silicon at 180 keV to a dose of 2×1017 cm-2 for the study of buried silicide synthesis was analyzed by a 1 MeV helium ion microprobe with a spot size of 4 µm. RBS-mapping and RBS-tomography images successfully indicated lateral and cross-sectional nickel distributions at the surface and the projected range without etching or cleaving. A micro-RBS spectrum revealed that a small amount of nickel scattered off the mask edges during implantation exists within a masked region.
Charge Storage Phenomena and I-V Characteristics Observed in Ultrathin Polyimide Langmuir-Blodgett Films
Authors: Mitsumasa Iwamoto Mitsumasa Iwamoto , Atsushi Fukuda Atsushi Fukuda
Published: February 2005

We fabricated Au/PI/Al junctions and then examined the charge storage phenomena in polyimide (PI) layers. We also examined the current-voltage (I-V) characteristics of the junctions in connection with charge storage phenomena. It was found that numerous excess charges were injected into PI multilayers from electrodes by the application of biasing voltages. Therefore, the space charge field formed in as-deposited PI layers was distorted by the excess charges injected. It was also found that asymmetric I-V characteristics observed for Au/PI/Al junctions depended on the biasing voltages, because the space charge field formed in PI layers influenced the I-V characteristics.
Electrically Induced Ferroelectric Phase Transition of Copolymers of Vinylidene Fluoride and Trifluoroethylene
Authors: Ikeda Susumu , Hideshige Suzuki Hideshige Suzuki , Shinji Nagami Shinji Nagami
Published: February 2005

The ferroelectric phase transition of copolymers of vinylidene fluoride and trifluoroethylene was studied by means of measurements of dielectric constants under a bias electric field. Phase transition temperatures for unpoled samples initially shifted to lower temperatures with the bias field in the region of the small electric field, but to higher temperatures under large bias field. Thermodynamical analysis of the phase transition in poled samples in terms of Clausius-Clapeyron and Ehrenfest equations determined the thermodynamical order of the phase transition.
Epitaxial Growth of CuGaS2 by Halogen Transport Method
Authors: Osamu Igarashi Osamu Igarashi
Published: February 2005

CuGaS2 was epitaxially grown on (001) GaP and (110) GaAs by the halogen transport method. Orientation relationships in these cases were (a) [001]CuGaS
2//[001]sub and [100]CuGaS
2//[100]sub, and (b) [001]CuGaS
2//[001]sub and [110]CuGaS
2//[110]sub, respectively. Results of the growth on the other faces of the substrates (involving sapphire) were as follows. (1) On (001) GaAs, although the growth occurred with the relationship of (a) (or (c) [001]CuGaS
2//[010]sub and [100]CuGaS
2//[001]sub), twinning about [221] and [2̄2̄1] (or [22̄1] and [221̄]) was observed. (2) The growth on (11̄02) Al2O3 was essentially the same as (1). (3) On (110) GaP, the coexistence of two relationships, (c) and (d) [001]CuGaS
2//[100]sub and [010]CuGaS
2//[001]sub, was observed. (4) The CuGaS2 deposited on (0001) Al2O3 was composed of six sets of (112)-orientated crystallites which were rotated every 60° about the normal of the substrate surface. (5) On (111)B GaP, in addition to the result of (4), twinning about [2̄21] was observed.
Thickness Control of Multilayer Films in Laser-Induced Chemical Vapor Deposition
Authors: Mutoh Katsuhiko , Yamada Yuka , Takashi Iwabuchi Takashi Iwabuchi , Takeo Miyata Takeo Miyata
Published: February 2005

The authors propose a sequence-control method for layer thicknesses by changing deposition time in the chemical vapor deposition with nonconstant deposition rates due to films deposited onto the laser-beam transmitting window. The method is applied to tungsten-carbon multilayer depositions using an ArF excimer laser.
Influence of Contamination in Repeated Depositions on the Properties of Diamond Films
Authors: Watanabe Ichiro , Takashi Yamashita Takashi Yamashita , Masato Sugimoto Masato Sugimoto
Published: February 2005

Carbon contamination attached to a reaction system during the growth of diamond films by microwave plasma chemical vapor deposition elicits a decrease in the growth rate of the films, but it does not result in appreciable change in the quality of the films. Good reproducibility in the growth rate is attained by plasma etching of the contamination by carbon tetrafluoride with a small amount of oxygen.
Nonequilibrium Rotational Energy Distribution in NH3 Supersonic Molecular Beam
Authors: Tanaka Yoshihito , Tachikawa Maki , Matsushima Fusakazu , Yoshihiko Uematsu Yoshihiko Uematsu , Tadao Shimizu Tadao Shimizu
Published: February 2005

The energy distribution among rotational levels of NH3 molecules in a supersonic beam is measured at a position distant from the nozzle by the highly sensitive infrared laser Stark spectroscopic method. A nonequilibrium energy distribution is observed within the rotational degree of freedom. In particular, population inversion is observed on some rotational levels. Computer simulation based on a novel rate-equation model, in which the dipole-dipole interaction, detailed balance, and hard-sphere collisions are assumed, reproduces the observed results well. This model is able to characterize the internal energy distribution of a supersonic beam under various experimental conditions by means of a scaling parameter.
A New Type of Ultralight Flexible a-Si Solar Cell
Authors: Kishi Yasuo , Inoue Hiroshi , Murata Kenji , Kouzuma Shinichi , Morizane Masashi , Shibuya Hisashi , Hidenori Nishiwaki Hidenori Nishiwaki , Yukinori Kuwano Yukinori Kuwano
Published: February 2005

A new type of ultralight flexible a-Si solar cell fabricated on a transparent polyimide film substrate, has been developed. High photoconductivity (σph) of 2×10-5 Ω-1 cm-1 and high photosensitivity (σph/σd) of 1×106 were obtained with a-Si films deposited by H2-dilution of SiH4 on a transparent polyimide film substrate at 180°C. Prebaking the transparent polyimide film substrate effectively reduced the impurity content of the a-Si film. A maximum output power of 550 mW and a power-to-weight ratio of 275 mW/g were obtained for an integrated-type a-Si solar cell with a size of 110×115 mm.
Brewster and Pseudo-Brewster Angle Technique for Determination of Optical Constants
Authors: Makio Akimoto Makio Akimoto , Yasuo Gekka Yasuo Gekka
Published: February 2005

The analytic solution of the pseudo-Brewster angle, for the case of electromagnetic waves incident from a transparent optical material onto an absorbing material, has been obtained. We have developed a unique measurement method, called the pseudo-Brewster angle method, for obtaining the optical constants of thin films. By this method, the reflected intensity is measured at any angle of incidence. The optical constants are calculated from the pseudo-Brewster angle at the minimum value of the reflection coefficient. As a result, the pseudo-Brewster angle method is very useful for measuring the optical constants of a thin film.
Preparation of CoxFe3-xO4 Films in Aqueous Solution at 120-200°C by “Hydrothermal Ferrite Plating”
Authors: Itoh Tomoyuki , Zhang Qun , Tamaura Masanori Abe
Published: February 2005

By a hydrothermal ferrite plating method, we synthesized Fe3-x
Co
x
O4 (x=0∼1.3) films at temperatures of 90∼180°C and pressures of 15∼40 kg/cm2. The solubility limit of Co increases as temperature increases, from x=∼0.6 at 90°C to x=1.3 at 180°C. All of the films are polycrystalline with no preferential orientation, and the magnetization lies in the film plane. The magnitudes of the saturation magnetization of the films are smaller than those expected for bulk samples, probably because 1) Co2+ ions are oxidized to Co3+ in a nonmagnetic low spin state, and the concentration of Co3+ in the film is higher than that in bulk samples owing to strong oxidizing activity, or 2) nonmagnetic impurity phases exist in the film. The highest value of the coercive force is obtained for films of Fe1.7Co1.3O4 synthesized at 180°C, and reaches ∼1300 Oe.
Shot-Noise Limited Low-Frequency Intensity Noise of a Nd:YAG Laser
Authors: Kimio Tsubono Kimio Tsubono , Shigenori Moriwaki Shigenori Moriwaki
Published: February 2005

We have reduced the intensity fluctuation of a laser-diode-pumped Nd:YAG laser to the shot-noise level by controlling the diode current. The obtained relative-intensity noise is less than 10-7 in Hz-1/2 within the 100 Hz to 10 kHz range.
Time- and Space-Focusing Detector System for Real-Time Electron Beam Testing
Authors: Nakamae Koji , Ura Hiromu Fujioka
Published: February 2005

A new real-time detector system which enables time resolution in the picosecond region is proposed. The system combines the principle of time- and space-focusing actions and the operating principle of the streak tube. Secondary electrons extracted by high voltage are focused in time onto the center of a sweeping deflector and are focused in space onto the screen. Two models are designed in the first-order approximation. One model utilizes an electrostatic toroidal sector field which has simultaneous time- and space-focusing properties. The other model uses a retarding field for time focusing and electrostatic lenses for space focusing. The analyzed results in both models show that the time resolution of about 5 ps can be realized. The collection efficiency of emitted secondary electrons is in the order of 10-2.
Partial Melting of Yttrium-Excess YBa2Cu3OySuperconductors
Authors: Lee Eun-Hong , Seok Hyun Oh Seok Hyun Oh , Seok-Yeol Yoon Seok-Yeol Yoon
Published: February 2005

Yttrium-excess YxBa2Cu3Oy(1.00≤x≤1.25) superconductors have been fabricated by a combination process of ordinary solid-state reaction and partial melting. Sintering the yttrium-excess YxBa2Cu3Oyresults in extremely small grains, which in turn produce uniformly distributed fine Y2BaCuO5during partial melting. Y2BaCuO5acts as the nucleation site for peritectic reaction. The unreacted Y2BaCuO5seems to act as a flux pinning center. Due to this flux pinning force, the yttrium-excess YxBa2Cu3Oysuperconductors have very high critical current densities of about 22,000 A/cm2(at 77 K, 1 T).
YBa2SnO5.5: A New Phase in YBa2Cu3O7-SnO2System
Authors: Paulose K. V. , Murugaraj P. , J. Koshy J. Koshy , A. D. Damodaran A. D. Damodaran
Published: February 2005

A new compound, YBa2SnO5.5was found forming in YBa2Cu3O7-x-SnO2system. Preparation of YBa2SnO5.5as a single phase compound by solid state reaction method is reported for the first time. This new compound has a cubic structure with a lattice parametera=8.42 Å. Kinetics of sintering and its dielectric properties are briefly discussed. No chemical reaction between YBa2Cu3O7-xand YBa2SnO5.5was observed even at an elevated temperatue of 950°C. Sintered YBa2SnO5.5is proposed as a new substrate material for the preparation of superconducting YBa2Cu3O7-xthin films.
Reduction of Defects in the Single-Crystalline Bi-Sr-Ca-Cu-O Superconductor
Authors: Yasuda Takashi , Naoko Nonaka Naoko Nonaka , Shuzo Takano Shuzo Takano
Published: February 2005

Growth conditions in the KCl-flux method were refined to reduce defects in the platelike crystals of Bi2Sr2CaCu2O8+y
. Crystals were grown from high-temperature solutions by slow-cooling and subsequent isothermal processes in a horizontal temperature gradient. As a result, we succeeded in excluding defects that had been observed as etch pits in our previous study.
High Coercivity Maghemite Films by Spray-Pyrolysis
Authors: Chang Wei-Der , Deng Ming-Cheng , Tsepin Tsai Tsepin Tsai , Tsung-Shune Chin Tsung-Shune Chin
Published: February 2005

Maghemite films with coercivity of 1200-1300 Oe, saturation magnetization of around 5000 G, and squareness ratio of 0.63-0.66 have been routinely prepared by spray-pyrolysis onto heated substrates of alumina, MgO(100) and Corning 7059 glass from aqueous nitrate solutions containing Fe, Co, and Mn. Composition and reduction-oxidation treatments were found to dominate coercivity. Glancing angle X-ray diffraction showed a single phase maghemite structure. Transmission electron microscope (TEM) studies on detached film material showed that ultrafine equiaxed particles of 40 to 90 nm contribute to high coercivity. Post-annealing was found to enhance coercivity substantially. These films are potential candidates for magnetic recording media.
Plasma Etching of RuO2 Thin Films
Authors: Kuramasu Shinji Saito
Published: February 2005

Plasma etching of RuO2 thin films was studied. It was shown that reactive ion etching employing CF4 or O2 plasma is effective in delineating RuO2 fine patterns. The etching rate was 2∼5 times higher than that for sputter etching. A higher etching rate and good selectivity were achieved using O2 plasma. This result can be explained by the difference in volatility of the respective reaction species.
Efficient Second-Harmonic Generation with a Slab Waveguide Composed of Periodically Corona-Poled Organic Copolymer
Authors: Azumai Yuji , Kishimoto Manabu , Heihachi Sato Heihachi Sato
Published: February 2005

Using the slab waveguide composed of spin-coated vinylidene cyanide/vinyl acetate (VDCN/VAc) organic copolymer having the square-shaped corrugation of nonlinear optical susceptibility χ(2) with corona discharge in the guiding layer, and taking quasi-phase matching between the dominant modes of both fundamental and second-harmonic waves, enhancement of second-harmonic generation (SHG) has been demonstrated at Nd:YAG 1.06 µm and Er:YAG 2.94 µm laser lines. The SHG power with this χ(2) corrugated slab guide is theoretically evaluated, together with its enhancement factor (E.F.) to a bulk scheme. The E.F. of 500 to 800 obtained in the experiments is consistent with the theoretical estimates.
High-Dose Implantation of MeV Carbon Ion into Silicon
Authors: Chayahara Akiyoshi , Kiuchi Masato , Horino Yuji , Kanenaga Fujii Kanenaga Fujii , Mamoru Satou Mamoru Satou
Published: February 2005

The formation of SiC in silicon wafer by 1.5 MeV C+ implantation to doses of 1.5×1018 ions/cm2 followed by annealing is demonstrated using infrared absorption spectra and Rutherford backscattering (RBS). From the results of He+ backscattering under the channeling condition, the surface layer of Si is observed to remain crystalline even before annealing.
Model Calculation of Morphological Parameters of Membrane Protein-Detergent Complex
Authors: Hamanaka Takeshi Kawaguchi
Published: February 2005

A procedure of model calculation of the morphological parameters (volume, average electron density, radius of gyration of outer shape, first and second moments of electron density distribution, and square average of the electron density distribution) is described for several symmetric and asymmetric models proposed for the membrane protein-detergent complex. The parameters calculated with the procedure can be compared with the observed ones. The coincidence of the two values is necessary to determine the model parameters in addition to the best fitting of intensity curves.
Thermal Annealing Studies of Boron-Implanted HgCdTe by Electrolyte Electroreflectance
Authors: Chao Shi-Chen , Hsu Kuo-Tung , Jan Gwo-Jen , Juang Feng-Yuh , Chang Tin-Fung , Wu Jia-Song
Published: February 2005

The thermal annealing properties of B+ implantation in HgCdTe are investigated by the electrolyte electroreflectance technique. The various thermal annealing conditions, such as temperature, time, and presence or absence of ZnS encapsulated passivation, are used as parameters to study the surface properties of HgCdTe and are characterized by electrolyte electroreflectance spectroscopy. We found that Hg accumulates near the surface region of an encapsulated sample, and Hg is lost at a depth of 1600 Å. The quality of the crystal is much improved when the sample is annealed at 200°C for a duration of over 30 minutes.
Measurement of Electron Energy Distribution Function in a Low-Pressure rf Discharge Plasma
Authors: Yagura Shinya , Okuno Yoshihiro , Yasunori Ohtsu Yasunori Ohtsu , Hiroharu Fujita Hiroharu Fujita
Published: February 2005

Electron energy distribution functions in a low-pressure rf discharge (<1 mTorr) were measured with an electrostatic energy analyzer facing the powered electrode and the bulk plasma. Electrons with high energy were observed in the former case, whereas the distribution of electrons was almost Maxwellian in the latter case.
Development of Microwave Caliper for Sheet Materials
Authors: Shigeru Nakayama Shigeru Nakayama
Published: February 2005

A microwave caliper used for performing noncontact measurements of the thickness of dry sheet materials is developed using a microwave coaxial cavity resonator. Since the coaxial cavity is open-ended on one side, even a thick sheet material can be measured. High resolution of thickness is obtained due to a strong electric field on the open circuit plane of the cavity. The fringing electric field distribution of the open-ended coaxial cavity, which has been difficult to observe, is monitored as a thermal distribution by a thermography. The frequency shift of a resonance peak is found to be closely related to the dielectric constant.
Energy Dependence of Sensitivity and Its Control by Electrode Design in a-Si:H/c-Si Heterojunction Gamma-Ray Detectors for Dosimeters
Authors: Sato Noritada , Okamoto Eisuke , Suzuki Toshikazu , Yasukazu Seki Yasukazu Seki
Published: February 2005

In conventional semiconductor high-energy photon detectors, photon-counting sensitivity decreases with increasing photon energy. To use semiconductor detectors for dosimeters, we need to reduce this energy dependence of the sensitivity to within ±20% variation in the photon energy range of 60 keV to 6 MeV. This can be realized by detecting secondary electrons generated by high-energy photons in the undepleted region around the depleted region. In studies on the design of an efficient pattern and size for such electrodes based on this principle, we found that, for an a-Si:H/c-Si heterojunction detector, an asterisk-patterned electrode composed of a 1-mm-dia. circle with 4 to 6 projections can satisfy the required energy dependence of the sensitivity.
Au Wire Bonding to Cu Pad Using Ti Thin Film
Authors: Hiroshi Ueno Hiroshi Ueno
Published: February 2005

An improved multilayer structure of a metal pad is developed for Au wire bonding to a monolithic IC. The proposed structure of the pad is Ti(2.5 nm)/Cu(800 nm)/Ti(70 nm)/Al(130 nm) on SiO2/Si substrates. Thermosonic Au wire bonding to the pad shows good bondability after heating at 473 K for the storage time of 3.6 ks in air. During heat treatment at 473 K after bonding, the bond between the Au wire and the pad is not degraded.
Radar Cross-Sectional Spectra of Rotating Multiple Skew-Plated Metal Fan Blades by Physical Optics/Physical Theory of Diffraction, Equivalent Currents Approximation
Authors: Bor Sheau-Shong , Tai-Lin Yang Tai-Lin Yang , Shui-Yuan Yang Shui-Yuan Yang
Published: February 2005

The monostatic radar cross-sectional spectra of rotating multiple skew-plated metal fan blades are investigated. The theoretical treatment of such a slowly rotating and electrically large scatterer is based on the quasi-stationary method together with physical optics/physical theory of diffraction (PO/PTD) equivalent current techniques. Only the θθ polarization case is considered here, but the φφ polarization case can be treated in the same way. This solution is applicable to any observation angle, and is represented by such a general form as one which enables us to treat a similar scatterer with multiple blades and with different skew angles. Three rotating skew-plated blades are taken as an example, and the agreements between the theoretical and experimental results are satisfactory.
Characteristics of Bipolar Transistors with Various Depths of n+ Buried Layers Formed by High-Energy Ion Implantation
Authors: Tamba Akihiro , Kobayashi Yutaka , Suzuki Tadashi , Natsuaki Nobuyoshi
Published: February 2005

Bipolar transistors having n+ buried layers of various depths formed by high-energy ion implantation are investigated in order to obtain bipolar transistor of various performances in a single chip. The breakdown voltage between the emitter and the collector (B
V
CEO) values are controlled and decreased with increasing oxide thickness with high-energy ion implantation in Si dioxide films of varying thicknesses. The maximum B
V
CEO value obtained is 7.8 V. Base-collector leakage currents are very small when secondary defects are contained within the n+ buried layer. This method should be very effective for designing both BiCMOS and multifunction LSIs.
Transmission and Reflection at Butt Joints between Isotropic and Anisotropic Single-Mode Slab Waveguides
Authors: Geshiro Masahiro , Hotta Masashi , Sawa Haruo Kanetake
Published: February 2005

Transmission and reflection properties are studied for a butt joint between an isotropic slab waveguide and an anisotropic one consisting of uniaxial crystalline material which has the optical axis in the plane defined by the propagation axis and the normal of the waveguide surface. The effects of axial displacement and angular misalignment are discussed on the basis of numerical results obtained from two different formulas: one is derived from the boundary condition together with the modal orthogonality and the other is based on the simple overlap integral of modal profiles. It is confirmed that the simple formula in terms of the overlap integral is applicable to the characterization of butt joints involving anisotropic waveguides.
Analysis of Arbitrary Cross-Section Core and Arbitrary Index Profile Weakly Guided Dielectric Waveguides
Authors: Hao Ding Hao Ding , Xinzhi Chen Xinzhi Chen
Published: February 2005

The iterated moment method (IMM) is improved in this paper to make it suitable for the analysis of step-index or graded index arbitrary cross-section core and/or arbitrary index profile weakly guided dielectric waveguides. The advantages of IMM, such as the simplicity and the rapidity are still preserved. For all types of waveguide analyzed in this paper, a third order approximation is sufficient to give a reasonable precision.
Coupling Efficiency between Domed Structure LEDs and Gradient Index Fibers
Authors: Oikawa Eva Acosta
Published: February 2005

A model of the coupling of a laser emitting diode (LED) with domed structure and a multimode gradient-index fiber using high numerical aperture (NA) planar microlenses (PML) is analyzed by means of geometrical optics. The relative positions of LED, PML and fiber for maximizing efficiency are determined.
Modal Coupling Analysis for the Design of Nonburied and Buried Integrated Optical Components
Authors: Jesús Liñares Jesús Liñares
Published: February 2005

The transverse coupling efficiency between planar waveguides and optical planar components is studied by the scalar variational principle. Several refractive-index profiles are analyzed, describing ionic and proton exchanges in glass and lithium niobate, for fabricating nonburied, buried or partially buried graded-index waveguides. The transverse coupling efficiency's influence on the design of integrated optical components is stressed.
Design of an Aberration-Free Spherical Micro Lens with a Diffractive Relief Grating Film on a Refractive Spherical Glass Substrate
Authors: Mori Kenya Goto
Published: February 2005

A combined micro-objective lens for optical disc use has been developed. The lens consists of a thin relief diffraction grating film and a planoconvex glass substrate. The combined lens, which is called the spherical grating lens (SGL), is inherently a spherical lens, but has some interesting features such as high numerical aperture and “spherical aberration”-free. The aberration in the refractive substrate is canceled by a thin diffraction grating film. This paper shows the ray tracing design of the SGL and the calculation results, and finally, the experimental results show that the SGL can he used as a low-cost objective lens in the optical disc head if it is appropriately designed.
Axially Controlled Solid-Phase Crystallization of Amorphous Silicon
Authors: Hasegawa Seiichi , Takuya Nakamura Takuya Nakamura , Yoshihiro Kurata Yoshihiro Kurata
Published: February 2005

The crystallization behavior of a-Si films has been investigated as a function of the annealing temperature T
a (530-1100°C) and time (0-72 h) by means of X-ray diffraction, transmission electron microscopy (TEM) and Raman scattering. The a-Si films were deposited by low-pressure chemical vapor deposition (LPCVD) onto poly-Si films with a strong <110> texture prepared by plasma-enhanced CVD (PECVD) [poly-Si(P)], and onto fused quartz substrates [poly-Si(Q)]. Poly-Si(P) films were crystallized maintaining the same strong <110> texture as the PECVD poly-Si substrate, over the entire T
a range. However, poly-Si(Q) films exhibited a weak <111> texture. The final grain size estimated by TEM for poly-Si(P) films was independent of T
a, but became 7-8 times larger than that for the poly-Si substrate. The crystallization mechanism of poly-Si(P) films was discussed in comparison with that of poly-Si(Q) films.
Design and Fabrication of Silica-Based Waveguide-Type (3×3) Directional Couplers with Two Identical Outer Waveguides
Authors: Takagi Akihiro , Kaname Jinguji Kaname Jinguji , Masao Kawachi Masao Kawachi
Published: February 2005

We analytically and experimentally demonstrate the design and fabrication of silica-based waveguide-type (3×3) directional couplers with emphasis on the wavelength-flattened responses of the couplers when the center guide is excited. Complete optical power transfer from the center guide to the two outer guides, which corresponds to a 0.5:0:0.5 splitting ratio (3 dB coupler), is attained with slightly wider outer guides. Wavelength-flattened splitting ratios of 0.33:0.34:0.33 (5 dB coupler) or 0.1:0.8:0.1 (10 dB coupler) over a wide range from 1.3 µm to 1.55 µm are obtained with larger differences between the widths of the center and two outer guides. When the light is launched into one of the outer guides, complete power transfer is always obtained for the outer-to-outer path but not for the outer-to-center path, reflecting the waveguide symmetry of (3×3) structures. These experimental results are in good agreement with results calculated using the beam propagation method (BPM).
Integration of Free-Space Interconnects Using Selfoc Lenses: Image Transmission Properties
Authors: Kenjiro Hamanaka Kenjiro Hamanaka
Published: February 2005

A novel optical interconnection system which consists of cascade arrays of Selfoc lenses, has been proposed. An alignment-free optical mother board which has many comjugate image planes and the Fourier planes composed by the lenses is available for integrating many kinds of free-space optical systems. The system has the advantages of easy assembly and high reliability, in addition to a large space-bandwidth product and flexibility. Its concept, optical designs and image transmission properties evaluated through basic experiments and ray tracing estimations, are discussed.
Two-Dimensional Optical Buses for Massively Parallel Processing
Authors: Mizoguchi Shigeru Kawai
Published: February 2005

Optical interconnections using two-dimensional waveguides are presented. Light beams whose incident angles are greater than the critical angle of a waveguide can propagate within that waveguide, which behaves as an optical bus. Such optical buses are suitable for massively parallel processing because they have a large number fan-outs and no skew. Estimated propagation distance in the waveguides is roughly 500 mm. One to several hundred interconnections may be achieved. Glass plates with concave lenses are used to demonstrate bus operations.