bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Resolution Electron Microscopic Study of Oxides Formed by Coalescence of Smoke Particles of Bi2O3 and WO3
Authors: Kaito Chihiro , Fujita Kazuo , Shiojiri Makoto
Published: November 2005

The structure of particles in a mixture of Bi2O3 smoke and WO3 smoke prepared by gas evaporation have been investigated using crystal lattice images obtained by high-resolution electron microscopy. The particles consist of Bi2O3·WO3, 7Bi2O3·WO3 and 7Bi2O3·2WO3, as well as Bi2O3 and WO3 and peritectic mixtures and eutectic mixtures formed by these oxides. The peritectic oxides are precipitated in two parts–one phase rich in the center and the other phase on the surface layer. The eutectic oxices are segregated into two phases in lamella form, with definite mutual lattice orientations. The crystals are formed by coalescence of Bi2O3 and WO3 particles above 400°C, and result in low-temperature phases presented in the phase diagram.
Superconducting Properties and X-Ray Analysis of Nb3Si Produced by Shock Synthesis
Authors: Ohshima Shigetoshi , Wakiyama Tokuo , Goto Tsuneaki , Syono Yasuhiko
Published: November 2005

Shock loading experiments were carried out on arc-melted Nb3Si over the pressure range 50–110 GPa using a two-stage light gas gun. T
c for the superconducting phase observed in specimens subjected to shock was 18 K and -(dH
c2/dT) was 1.23 tesla/K. The observed high-T
c phase is most probably A-15 Nb3Si transformed from the tetragonal Nb3Si (Ti3P type) phase during shock loading.
8.5% Efficient Screen-Printed CdS/CdTe Solar Cell Produced on a 5×10 cm2 Glass Substrate
Authors: Matsumoto Hitoshi , Nakano Akihiko , Komatsu Yasumasa , Uda Hiroshi , Kuribayashi Kiyoshi , Ikegami Seiji
Published: November 2005

The preparation conditions of CdS sintered film for 5×10 cm2 screen-printed CdS/CdTe solar cells were investigated. Increasing the belt speed of the belt furnace increased the residual amount of Cl ions in the CdS sintered film and lowered the efficiency of the cell. The optimum belt speed was 2 cm/min, corresponding to a sintering time of 90 min. The thickness of the CdS film was changed by changing the screen thickness. Increasing the thickness of the CdS film lowered its surface resistivity and improved the fill factor of a cell. A solar cell of 8.5% intrinsic efficiency was obtained from CdS film printed by an 80 mesh screen and sintered at 690°C at a belt speed of 2 cm/min.
Observation of Luminescent Lines Related to Pseudodirect Gap in ZnSiP2 Crystals
Authors: Nishida Hideki , Shirakawa Tsuguru , Konishi Masaya , Nakai Junkichi
Published: November 2005

The photoluminescence of ZnSiP2 crystals has been measured at 4.2 K. New sharp emission lines were observed at about 1.980 eV in a sample annealed at 400°C in vacuum. The intensity of these lines is greatly enhanced by excitation at the exciton absorption peak associated with the pseudodirect gap. This indicates that these emission lines are due to the bound excitons associated with the pseudodirect gap, in contrast to the results of previous photoluminescence measurements suggesting that this crystal is an indirect-gap semiconductor.
DLTS Study of RIE-Induced Deep Levels in Si Using p+n Diode Arrays
Authors: Watanabe Miyoko Oku , Taguchi Minoru , Kanzaki Koichi , Zohta Yasuhito
Published: November 2005

Deep levels in Si induced by reactive ion etching (RIE) of SiO2 film have been studied by DLTS. In order to detect the RIE-induced damage existing near the surface region, special device structures consisting of p+n diode arrays are used. It is found that the dominant deep levels produced by RIE are four hole traps. One level at E
v+0.40 eV exhibits the Poole-Frenkel effect, from which it is identified as an acceptor. Another level at E
v+0.46 eV is deduced to be an interstitial iron level from the emission rate. There is a strong decrease in the deep level concentrations upon annealing above 500°C. However, the deep levels do not completely disappear upon annealing at high temperatures. The deep level concentrations correlate well with the current-voltage characteristics of the devices.
Coupling Properties of Phased Waveguides in LHRF Heating Experiment in JFT-2 Tokamak
Authors: Fujii Tuneyuki , Imai Tsuyoshi , Uehara Kazuya , Nagashima Takashi
Published: November 2005

A phased array of four waveguides was used as the wave launching system in an LHRF heating experiment in the JFT-2 tokamak. The coupling properties, particularly the reflection coefficient were investigated up to a power of 250 kW. The lack of dependence of the reflection on the phase difference Δφ at the high power of 70 kW obtained in an early experiment with an aluminium launcher is well explained by a theory in which the dissipation due to discharge is taken into account. After the launcher was improved in order to suppress the discharge, the reflection depended on Δφ even at a high power of 100 kW. Also, the reflection depended on the power density up to 16 MW/m2. This result agrees with these obtained from a linear theory in which a small modification due to ponderomotive force is incorporated.
Application of Fission Chamber to Uranium Microanalysis
Authors: Yamada Kimio , Izumi Shigeru , Otsuka Hisao , Matsumoto Tetsuo
Published: November 2005

The possibility of using a fission chamber for quantitative analysis of uranium impurity in dynamic memory materials was studied. The fission chamber had two pairs of parallel disk electrodes. One electrode of each pair was used as a collector and was made of Teflon with a pure aluminum coating, while the other electrode was the material to be measured. Carbon dioxide was used as the ionization gas.
Uranium in the materials was irradiated with neutrons and the number of fissions was counted to give the impurity content. Uranium contents in aluminum (99.8%) and Teflon were calculated, and measured values showed a fairly good reproducibility. The detection limit, determined by background fluctuations, for uranium impurity contained in the aluminum coated Teflon electrode was 4.0 ppb.
Time-Dependent T-T Absorption in Anthracene Derivatives Deduced from Reabsorption Effect
Authors: Shimura Hiroshi
Published: November 2005

The fluorescence decay time for anthracene derivatives in solution is measured, and the time variation of the reabsorption effect is calculated by applying the Stern-Volmer type equation to the decay time. The time variation of T-T absorption is then deduced from this. The derivatives examined here can be classified into three groups according to the features of the T-T absorption. Group A, represented by 9,10-diphenylanthracene, shows little T-T absorption; group B, represented by 9-methylanthracene, shows an increase in T-T absorption with time; and group C represented by anthracene, has an anomalous characteristic. Our classification corresponds to Ferguson's, which is concerned with quantum efficiency.
A 6-Meter Neutron Small-Angle Scattering Spectrometer at KUR
Authors: Komura Shigehiro , Takeda Takayoshi , Fujii Hironobu , Toyoshima Yoshinori , Osamura Kozo , Mochiki Koichi , Hasegawa Ken'ichi
Published: November 2005

A 6-meter neutron small-angle scattering spectrometer has been constructed at Kyoto University Reactor (KUR) and has been used successfully for various fields of application in these three years. This paper describes overall design principles and the characteristics of the various parts of the spectrometers which can be assembled and disassembled easily at KUR. Some examples of scattering measurements are presented to show the performance of the spectrometer.
A Stable In-Laboratory EXAFS Measurement System
Authors: Ito Masahisa , Iwasaki Hitoshi
Published: November 2005

An EXAFS measurement system with two proportional counters has been constructed. One of the counters is for monitoring the incident X-ray intensity, and the other is for measuring the intensity after the X-rays have passed through the specimen, and has an adjustable length. As the intensities before and after the specimen are measured simultaneously, the system is free from fluctuations of the incident X-ray intensity. By adjusting the length of the latter counter, error caused by the counting loss effect at the energy of the characteristic X-rays of impurities contained in the X-ray tube target has been removed. The EXAFS spectrum of Zn sites in amorphous Mg70Zn30 alloy is measured with this system.
Influence of Radial Diffusion Loss of Electrons on Ionization Waves Produced by Spatial Resonance
Authors: Miura Kosuke , Yamazaki Tsutomu , Imazu Shingo
Published: November 2005

The spatial resonance which produces non-hydrodynamic ionization waves is investigated theoretically, with the radial potential distribution of φ(r)=φw(r/R)land the radial diffusion loss of electrons being taken into account. It is found that the radial diffusion loss of electrons disturbs the spatial resonance. Since the radial diffusion loss is suppressed markedly by increasing the axial magnetic field, spatial resonance is likely to occur in the magnetic field if the energy loss due to elastic collisions is small. Other effects of the axial magnetic field on facilitating or suppressing the spatial resonance are also disscussed.
Motions of Individual Dislocations in White Tin Single Crystals Deformed in Tension
Authors: Ojima Kozo , Hirokawa Tomoo
Published: November 2005

The motions of individual dislocations and dislocation arrangements in white tin single crystals deformed in tension were closely investigated using the etch hillock technique. When dislocations of the slip system (010) [100] move, they form bands (A-bands) which contain a high density of dislocations and run nearly perpendicular to the direction of motion of the dislocations. Such bands are formed from two groups of dislocations which approach each other from opposite sides. The motions of dislocations during and after unloading were also investigated.
The A-band has some dislocation-vacant areas which are frequently surrounded by dislocation arrays aligned in a direction inclined by about 45° to the direction of motion of the dislocations.
Discharge Production of S(1S) and the Effect of He as a Buffer Gas in Its Quenching Rate
Authors: Takatsu Norihiko , Hara Hideo , Kano Satoru S. , Takuma Hiroshi
Published: November 2005

It was demonstrated that the 1S state of sulfer atoms could be produced by discharge dissociation of OCS; the 1S state atoms were identified by observing the 772.5 nm auroral line fluorescence emitted from the afterglow of short pusle discharge of He gas containing 0.1% to 1.2% of OCS. The yield increased linearly with E/p up to 300 V cm-1 Torr-1. The fluorescence showed a single exponential decay. The decay rate constant was measured as a function of the buffer gas pressure and no evidence of quencher formation during the discharge was found.
Spectroscopic Laser Scanning Analysis of Photo-Induced Current on a-Si Solar Cells
Authors: Takakura Hideyuki , Fujimoto Koha , Okuda Koji , Coluzza Carlo , Hamakawa Yoshihiro
Published: November 2005

Spectroscopic analysis of the laser beam induced current (LBIC) has been carried out as a powerful tool for characterizations of spacial homogeneity and surface and junction interfaces in amorphous silicon (a-Si) solar cells. We have found the photocurrent inhomogeneity of a-Si solar cells and analyzed the origins of the fluctuation using the spectroscopic LBIC measurement. There are three kinds of fluctuation patterns, i.e., spikes based on the dust and scratch of the film, aligned sinusoidal fluctuation with short period upon the glass substrate thickness inhomogeneity, and relatively long period oscillation based on the a-Si junction interface situation.
It has also been revealed that a spectroscopic technique varing the wavelength of probe light makes it possible to know the in-depth profile of opto-electronic properties as well as optical properties of semiconductor devices.
Study on Young's Modulus and Internal Friction of Wood in Relation to the Evaluation of Wood for Musical Instruments
Authors: Ono Teruaki , Norimoto Misato
Published: November 2005

Young's modulus E and internal friction Q
-1 in longitudinal (L) direction and specific gravity γ were measured for numerous specimens of 25 softwood species. There was a high correlation between Q
-1/(E/γ) and E/γ, and the suitability of wood for musical instruments can be evaluated by using the value of E/γ. Furthermore, effects of grain angle in the longitudinal-radial plane on Young's modulus and internal friction of wood were investigated. From these results, it is concluded that the value of internal friction as well as Young's modulus of wood is determined in large part by microfibril angle in the S2 layer of tracheid against the L direction.
A Waveform Reproduction Study of Time Domain Reflectometry. I. Reflections from a Diffuse Interface between Two Miscible Layers
Authors: Hayashi Shigeo , Aihara Ariyuki
Published: November 2005

An iterative waveform-fitting procedure is presented that enables one to analyze TDR waveforms reflected from a wider class of samples than hitherto taken up. In the procedure one calculates the inversion of the Laplace transform, r(s)θ(s)/s, where r(s) is the reflection coefficient and θ(s) accounts for the characteristics of the particular setup employed. To confirm the reliability of the calculations involved, the procedure is applied to multiple reflections from water, tetrahydrofuran, and cyclohexane-water layers, resulting in good agreement with experimental waveforms. Subsequently it is applied to a system consisting of tetrahydrofuran and water layers in which a diffuse interface exists between the layers, producing the concentration distribution of the substances along the axis successfully.
Feasibility of the LPE Growth of AlxGayIn1-x-yP on GaAs Substrates
Authors: Kazumura Masaru , Ohta Issey , Teramoto Iwao
Published: November 2005

The maximum direct bandgap energy of Al
x
Ga
y
In1-x-y
P lattice-matched to GaAs is found to be 2.17 eV at x=0.21 and y=0.34. This is the largest value among the III-V compounds with the zinc-blende structure. The phase diagram is calculated of the quaternary system Al–Ga–In–P. It is predicted that the LPE growth of Al
x
Ga
y
In1-x-y
P will encounter serious difficulties resulting from the extremely large segregation coefficient of aluminum. In fact, experiments have shown that aluminum is not incorporated into the crystals grown from the quaternary solutions because of the instant depletion of aluminum at the very early stage of the cooling process.
Deep Levels in InP Grown by MOCVD
Authors: Ogura Mototsugu , Mizuta Masashi , Hase Nobuyasu , Kukimoto Hiroshi
Published: November 2005

Deep levels in the undoped InP grown by MOCVD have been investigated by deep level transient spectroscopy (DLTS). Three electron traps MOE1, MOE2, MOE3 have been observed with activation energies of 0.37 eV, 0.53 eV and 0.60 eV, respectively, in the temperature range between 160 K and 380 K. The trap concentrations of these levels were from 1013 cm-13 to 1015 cm-3 for samples with carrier concentrations of (1-6)×10-16 cm-3. The electron capture cross sections (σn) have been directly determined to be 3.1×10-18 cm2 (at 206 K) for MOE1 and 8.8×10-19 cm2 (at 344 K) for MOE3. For the level MOE2, it has been found that the capture cross section is strongly dependent on temperature, i.e., temperature dependence of this cross section is experimentally well-characterized by the relation σn=4.2×10-12 (cm2) exp
(-0.38 (eV)/k
T), which indicates the multiphonon emission process occurring during an electron capture event. Two deep levels have also been found in the LEC InP substrate material, which are identical to the defects observed in the epitaxial layer.
Immiscibility in Type A1-xBxC1-yDy Strictly Regular Quaternary Solid Solutions. I. Unstable Regions
Authors: Onabe Kentaro
Published: November 2005

A generalized thermodynamic analysis is given on the unstable region behavior for type A1-x
B
x
C1-y
D
y
strictly regular quaternary solid solutions with positive pseudobinary interaction parameters as found in III-V quaternary solid solutions. An expression is derived for the spinodal curves. It is known that possible unstable region behaviors can be classified into three major categories, depending on the relative magnitudes of pseudobinary and quaternary interaction parameters. This fact is demonstrated by an extensive numerical calculation on the temperature dependence of unstable region extent. An approximate expression for quaternary critical temperature for a simple case is also shown.
Growth of Zinc Sulfo-Selenide Single Crystals and Their Near Band-Edge Photoluminescence
Authors: Huang Shi-Min , Satoh Shiro , Mochizuki Katsumi , Igaki Kenzo
Published: November 2005

High-purity ZnS
x
Se1-x
(0\leqslantx\leqslant0.15) single crystals have been grown by the sublimation method. Sharp emission due to free-exciton (Ex) has been observed for the first time in ZnS
x
Se1-x
. The bound-exciton (I2 and I1
deep) line and the LO-phonon replicas of I1
deep line have also been observed. Energies of their peaks shift towards higher energy with the increase of composition parameter x (0\leqslantx\leqslant0.15). With increasing x, the I1
deep emission line becomes broader and approaches a Gaussian shape. The intensity of I1
deep line decreases with increasing x and becomes hardly observable for x above 0.12.
Kinetic Study of LixWO3 Electrochromism
Authors: Nagai Junichi , Kamimori Tadatoshi
Published: November 2005

Coloring/bleaching processes of Li
x
WO3 electrochromism were examined in terms of emf, chronoamperometry, voltammetry and ac impedance measurements. The current-potential relation was found to be ohmic in the short time region and expressed by i=(E
app-emf (x))/R. Satisfactory fittings were obtained for chronoamperometry and voltammetry measurements on the basis of the assumption of diffusion-limited process with above i-E relation. Diffusion coefficient was estimated to be about 5×10-10 cm2/sec. It was elucidated from the detailed analysis of impedance that R was given by the summation of the resistances of solution, electrode, charge transfer and material transfer. Since it was found that the WO3 film was regarded as a large condenser with a serially connected resistor, color/bleach processes were understood as charging/discharging processes of WO3 film.
Time Structure Monitoring of the Electron Beam in a Linear Accelerator
Authors: Owaki Shigehiro
Published: November 2005

Together with the completion at Osaka University of an L-band linear accelerator which can produce single-bunch pulses, a time structure monitoring system to insure its stable operation was developed, and it has worked well for several years now. Electron pulses from the accelerator are injected into a gas filled radiator and are thereby converted to Cherenkov light which reflects the fast-time structure. After a flight path of 15 m, light pulses are analyzed by a streak camera with a time resolution of 9.6±1.0 ps. A minimum single-bunch width of electrons was estimated to be 27.6±7.2 ps. With this system, other parameters of electron pulses can also be evaluated.
Experimental Studies on Laser-Produced-Plasma-Initiated Reflex-Triode-Type Pulsed Ion-Beam Generator
Authors: Ogasawara Munehiro , Higuchi Yukishige , Sekiguchi Tadashi
Published: November 2005

Preliminary experimental results are shown on pulsed ion-beam generation by a reflex-triode scheme with a laser-produced anode plasma. An aluminum ion-beam maximum ion energy of about 3 MeV and peak ion-beam current of 100–200 A has been extracted mainly to the virtual-cathode side, by irradiating a Nd-glass laser with relatively low output energy (3–5 J) onto the virtual-cathode side of aluminum-foil anode surface. In addition, employing a mesh-anode, the existence of an optimum delay-time from laser-irradiation to the rise of anode voltage (∼220 ns in the present experiments) has been demonstrated.
Experimental Study on the Ionization of Argon behind Reflected Shock Waves
Authors: Terao Kunio , Hozaka Masato , Kaitoh Hiroaki
Published: November 2005

The electron temperature and density along with the ion temperature in argon gas behind reflected shock waves were measured by laser light scattering, while the spectroscopic temperature was measured from the ArI line emissions. The values of these three temperatures are different from each other for a few hundred microseconds after arrival of the reflected shock front. Both the electron and ion temperatures are much higher than the theoretical gasdynamic temperature, while the spectroscopic temperature is lower than the theoretical one. The degree of ionization is much higher than that in the equilibrium state. The stochastic character of the ArI line emissions was observed, indicating that the gas is inhomogeneous. These phenomena are explained as follows: initially, the gas behind the reflected shock wave is inhomogeneous, and an associative ionization is initiated at some points. The gas becomes homogeneous mainly through diffusion.
Experimental Study of the Dependence of Extracted Beams on Source Parameters in Magnetron H- Ion Source
Authors: Okamura Hideo , Kuroda Tsutomu , Miyahara Akira
Published: November 2005

Experimental results are given for the relations between the H- ion current and the magnetic field, gas feed rate and cathode temperature in a pulsed magnetron source with stainless steel cathode. Results are discussed on the basis of surface production model, showing importance of cathode surface temperature for H- generation and gas thickness for H- destruction. The influence of extraction gap distance on parasitic electron current and beam divergence is examined and the current flow of extracted charged particles is given schematically.
Conceptual Design of Proton Computed Tomography with Magnetic Spectrometer
Authors: Akisada Masayoshi , Ohashi Junichi , Kondo Kunitaka , Kurihara Daiki , Miyashita Shigeyuki , Tachikawa Akira , Takada Yoshihisa , Takikawa Koji
Published: November 2005

A new and unique method of proton computed tomography is proposed. Integrated electron-density distributions along a few tens of parallel paths are obtained at once by precisely measuring the energies of incident and outgoing protons. The energy of the outgoing proton is measured by a magnetic spectrometer. With this method, a proton CT with high density resolution, high spatial resolution, and with lower dose can be realized in a short scanning time.
Magnetoelastic Wave Excitation Properties of Amorphous Iron-Boron Films Prepared by RF-High Rate Sputtering
Authors: Fujii Toshitaka , Kumura Tatsuo , Miyama Tomohiro , Inoue Mitsuteru
Published: November 2005

We investigated the magneto-acoustic excitation properties of amorphous iron-boron films prepared by rf-high rate sputtering by observing magnetoelastic wave resonance in linear samples. The longitudinal complex susceptibility was measured as a function of the external applied field. Films about 10 µm thick were deposited onto aluminum foil substrates. The observed magnetoelastic wave was a standing wave of the lowest mode. The controllable change in the velocity of sound by the application of an external field ΔC/C was about 4.7% for films with substrates. This value increased to 17% when films were removed from the substrate, the new value being comparable to that obtained in rapid-quenched Fe80B20 ribbons. The experimental results are explained very well by the one-dimensional string model, from which important magneto-acoustic quantities are derived.
Electronic Properties of Vapor-Grown Heteroepitaxial ZnO Film on Sapphire
Authors: Kasuga Masanobu , Ogawa Shinzi
Published: November 2005

Hall coefficient and resistivity measurements have been made on single-crystal ZnO films prepared by chemical vapor deposition on sapphire substrates from 4.2 K to 300 K. Successive reduction of the film thickness from the surface and the rear (interface to substrate) revealed that there are two regions–a bulk region and an interfacial region adjacent to the substrate. At the interfacial region, the carrier density is assumed to be very high and impurity-band conduction takes place. The dependence of the mean resistivity and the mean carrier density on the film thickness and temperature are described well by the two-layer and two-band model.
Effect of Deposition Rate and Substrate Temperature on Properties of CdTe Film
Authors: Kawai Yoshiji , Ema Yoshinori , Hayashi Toshiya
Published: November 2005

The effects of the deposition rate and the substrate temperature on the structure and the electrical and optical properties of CdTe film evaporated on an Au-coated glass substrate were investigated, and the film quality is discussed here. It is shown that the crystalline size decreased with the deposition rate and increased with the substrate temperature, and that the stoichiometry of the film was best at the deposition rate of 17 Å sec-1 at room temperature. At a lower deposition rate, the film became Cd-rich and n-type, while it became Te-rich and p-type at a higher deposition rate. The Cd content increased with the substrate temperature. The films deposited at lower rates were polycrystalline and those deposited at higher rates were amorphous. The film deposited at a rate of 17 Å sec-1 –19 Å sec-1 and a substrate temperature of 100°C showed the highest quality of all the films.
Overturning of Molecules in Built-Up Iron Stearate MML Examined by 55Fe-Tracer Technique
Authors: Mizuno Morishige , Mori Chizuo , Noguchi Hiroshi , Watanabe Tamaki
Published: November 2005

Langmuir-Blodgett iron stearate layer was deposited from aqueous surface onto a substrate only on down-journey. On up-journey the substrate was withdrawn through a clean area. The condition of aqueous surface was the same as for the preparation of Y-type layer. 55Fe-tracer technique was developed for the examination of the direction of molecules. With this technique one can determine the distance from surface to 55Fe atoms combined with carboxyl groups of stearate, and obtain the information on the direction of molecules in the deposited layer with respect to the substrate. The change of direction was observed owing to overturning of molecules. The present overturning is different from that reported previously for the occurrence in the built-up layers other than X-type.
Computer Simulations of Quench Properties of the 3 mφ×5 m CDF Solenoid with Quench-Back Effects
Authors: Mori Shigeki , Noguchi Masaharu
Published: November 2005

Quench properties of the 3 mφ×5 m (1.5 Tesla) CDF superconducting solenoid with a stored magnetic energy of 30×106 J were studied by computer simulations using the one-dimensional approximation. The quench-back effect induced with magnetic coupling between the coil and the support cylinder is included in the calculations. Maximum voltages and temperatures are substantially reduced with the quench-back compared with those calculated in the previous analysis in which the quench-back effect was not included.
Mechanical Anisotropy in Oriented Nylon 12
Authors: Hiramatsu Nobuyasu , Hirakawa Susumu
Published: November 2005

To investigate the mechanical anisotropy in oriented nylon 12, the direction of the hydrogen bond in thea-cplane of the α form was determined by wide-angle X-ray diffraction measurements under various pressures. The hydrogen bond of the α form is nearly parallel to the rolled plane, unlike in the γ form. The mechanical properties of unoriented and doubly-oriented samples were investigated by viscoelastic measurements. In all doubly-oriented samples, the temperature dependence of the storage moduli at 0° and 90° to the chain direction in the rolled plane exhibited a cross-over, which is interpreted in terms of the manner of connection between crystalline and amorphous regions. The storage modulus of the α-form sample in the 90° direction was higher than that of the γ form because of the difference in the direction of the hydrogen bond.
Transport Properties of Amorphous Silicon Films on Quartz Substrate
Authors: Chakrabarti B. , Chaudhuri S. , Pal A. K.
Published: November 2005

Electrical conductivity and thermoelectric power of vacuum evaporated a-Si films deposited onto quartz substrate were measured in-situ at a system pressure ∼10-6 Torr. Data were analysed with the well known Mott's relations and it was observed that conduction is governed by variable range hopping in the lower temperature region and by carriers excited into the localised states at the band edges at high temperatures.
Asymmetrical Lamb Dip in a High-Gain 3.5 µm Xenon Laser. II. Analysis of Experimental Results
Authors: Asami Shigeo , Gamo Hideya , Tako Toshiharu
Published: November 2005

An expression for the output power tuning curve of a single-mode gas laser is derived, considering the radial distribution of the gain of the laser medium, the partially-homogeneous broadening and the frequency shift due to atomic collisions. According to the analysis, the asymmetrical Lamb dip can be caused by dispersion focusing and also by the asymmetric atomic line shape function due to the collision effect. In a high-gain medium, the dispersion focusing effect is shown to be predominant over the collision effect in producing the asymmetry in the tuning curve. By applying a curve-fitting method to the output power tuning curve and ignoring the asymmetry of the atomic line shape function the Lorentz linewidth of the xenon 3.5 µm transition is obtained as a function of the discharge current and the xenon pressure. The natural linewidth (full width at half-maximum, f.w.h.m.) in the limit of vanishing pressure effect, ΔνL, is 4.17 MHz and the rate of increase of pressure broadening (f.w.h.m.), ∂(ΔνL)/∂p, is 1.57 MHz/Pa.
Ferroelectric Domain Structure of PbHPO4
Authors: Nakatani Noriyuki
Published: November 2005

Etching methods to delineate the ferroelectric domain structure of PbHPO4are presented. Geometrical configuration of antiparallel domains bounded by 180° walls were investigated by these methods. The cross sections of domains are generally lenticular or lamellar and stretched along thea-cplane. The direction of spontaneous polarization, which lies in thea-cplane, was accurately determined by the domain structure revealed by successive etching. It makes an angle of (9.9±0.8)° with thea-axis and is almost parallel to thea*-axis.
Conditioning Effect of Dielectric Breakdown in Liquid Helium
Authors: Kim Sanhyon , Terauchi Masaharu , Yoshino Katsumi , Inuishi Yoshio
Published: November 2005

In a non-uniform field with a needle-plane electrode system, the breakdown voltage V
b of a positive needle decreases as the number of breakdown events N increases, but that of a negative needle increases slightly with N. In a uniform field, the breakdown voltage decreases with increasing N. However, when the polarity of the voltage pulse is reversed after many breakdown events, V
b increases suddenly and then again decreases slightly with increasing N, tending to saturate.
These conditioning effects can be explained by the increase of the electron injection from the cathode due to the formation of a rough surface by the previous breakdown events.
Spectroscopic Measurements of Plasma Ion Density by Neutral Beam Probing
Authors: Ito Yoshifumi , Fukumoto Shintaro , Goto Seiichi , Ishimura Tsutomu
Published: November 2005

A method of determining plasma ion density by spectroscopic measurement of line emission from a probing neutral beam, attenuated by resonance charge transfer interaction with plasma ions, is proposed and tested. A hydrogen plasma produced by an R.F. discharge was used as the subject of the test. The parameters of the hydrogen probing beam in the region of observation were ∼400 eV average energy, ∼3×1012 cm-3 peak density and ∼2 µs pulse width. The beam was produced by a z-pinch-gun, a neutral beam source. From the attenuation rate of Hβ emission and the known cross-section of the interaction, the ion density was determined when it was in the range from 2×1014 cm-3 to 5×1014 cm-3. The value determined agreed well with the electron density measured with an He–Ne laser interferometer.
A Non-Destructive Method for Measuring Lifetimes for Minority Carriers in Semiconductor Wafers Using Frequency-Dependent ac Photovoltages
Authors: Munakata Chusuke , Honma Noriaki , Itoh Haruo
Published: November 2005

A chopped photon beam, whose wavelength was 1.15 µm, irradiated a Si p-n junction (solar cell) through a transparent electrode and a mylar sheet. The chopping frequency was varied from 2 Hz through 200 kHz. Ac photovoltages were capacitively measured while changing the frequency. On a logarithmic scale, there appeared two bending points on the photovoltage vs frequency curve. Using the frequency at the second bending point, the lifetime for minority carriers in the substrate wafer was obtained. The observed value of 5.1 µs agreed well with that of 5.5 µs obtained by the conventional wavelength-dependent photocurrent method.
Improvement of Sensitivity of Electron Energy Loss Spectroscopy
Authors: Koma Atsushi , Yoshimura Kazuki
Published: November 2005

A new method has been developed to drastically increase the sensitivity of the low-energy electron energy loss spectroscopy. This method uses a pulse counting technique to detect a small number of analysed electrons and a difference formula to obtain the second-derivative spectrum. A personal-computer-controlled system has been developed for this purpose and the usefulness of the present method is demonstrated.
Ohmic Contact Properties of Magnesium Evaporated onto Undoped and P-doped a-Si: H
Authors: Matsuura Hideharu , Okuno Tetsuhiro , Okushi Hideyo , Yamasaki Satoshi , Matsuda Akihisa , Hata Nobuhiro , Oheda Hidetoshi , Tanaka Kazunobu
Published: November 2005

We have investigated the current-voltage characteristics of metal/undoped a-Si: H/n
+ (or p
+) c-Si structures using Mg, Au, Pt and Al. It has been indicated that the energy band of undoped a-Si: H shows a downward bending against Mg, being analogous to n
+
a-Si: H/undoped a-Si: H contact, while the band shows an upward bending against Au, Pt and Al. Mg/undoped a-Si: H contact is found to allow injection of electrons into the conduction band of a-Si: H, providing us a good ohmic contact property. This contact does not exhibit the thermal-degradation at least up to 100°C.
Resolution of Cu Atoms in a GP[1] Zone in Al–Cu by FIM and Determination of the GP[1] Structure
Authors: Mori Tsutomu , Wada Minoru , Kita Hideki , Uemori Ryuji , Horie Shiro , Sato Akikazu , Nishikawa Osamu
Published: November 2005

By FIM the atomic arrangement of a GP[1] zone in an aged Al–Cu alloy is resolved into isolated spots on the {024} planes. These resolved spots are identified as the images produced by individual Cu atoms of the GP[1] zone protruding on the {024} surfaces. By observing the position and shape formed by the spots corresponding to the Cu atoms during the successive field evaporation, it is concluded that a GP[1] zone consists of a single layer of Cu atoms on the {002} planes.
Parallel Electron Transport and Field Effects of Electron Distributions in Selectively-Doped GaAs/n-AlGaAs
Authors: Inoue Masataka , Inayama Minoru , Hiyamizu Satoshi , Inuishi Yoshio
Published: November 2005

It is demonstrated that a high electric field has large effects on the electron distribution and mobility in selectively doped GaAs/n-GaAs heterostructures. An increase of electron density in the AlGaAs layer has been found in the analysis of pulsed Hall effect and SdH oscillations at 4.2 K. At high fields, the mobility of two dimensional (2D) electrons has become slightly higher than the average mobility obtained by the pulsed Hall measurement. The velocity of 2D electrons reaches 3.8×107 cm/s at 4.2 K.
Breakdown in Vacuum by a Microwave Field Superposed with d.c. Voltage
Authors: Hayashi Yoji , Ikezawa Shunjiro , Takeda Susumu
Published: November 2005

The microwave breakdown and its suppression by superposing d.c. voltage was investigated at the frequency of 2.45 GHz with regard to the high power microwave techniques for heating fusion plasmas. An increase of about 60% in r.f. breakdown voltage was realized by superposing d.c. voltage of 1000 volts in the cavity, whose height was 2 cm, at the pressure of 1×10-4 Torr.
Continuum Spectrum Generation in a Multimode Fiber Using Two Pump Beams at 1.3 µm Wavelength Region
Authors: Nakazawa Masataka , Tokuda Masamitsu
Published: November 2005

Using two pump beams with wavelengths of 1.32 µm and 1.34 µm, a continuum spectrum in a multimode fiber is newly generated with relatively low pump power of 1.5 kW for each wavelength. The continuum spectrum is attributable to the superposition of sequential stimulated Raman scatterings and forced four-photon mixing processes.
Magnetostatic Surface Waves in a Slab with Nonuniform Fields by Partially Magnetic Shielding
Authors: Ikuzawa Yoshiaki , Chang Nion Sock , Matsuo Yukito
Published: November 2005

Resonance experiments of magnetostatic surface waves (MSSW's) controlled by field gradients in a YIG slab partially shielded in its center with an iron ring are reported. In the configuration, the field profile is bowl-shaped with a minimum at the center of a slab in the propagation direction of MSSW's. The results indicate that MSSW's can propagate in such a geometry with increasing the wavenumbers. In the presence of the field gradients, new mode resonance has also been observed in the transmission spectrum below the bottom field of ordinary MSSW resonance.
Effects of Platinum Diffusion on MOS System
Authors: Mori Seiichi , Kato Hideo , Kuwano Hiroshi
Published: November 2005

The properties of platinum-diffused MOS structures were experimentally investigated. It is pointed out that the amount of charge at the Si–SiO2 interface introduced by platinum diffusion is strongly dependent on a sort of diffusion ambient and crystal orientation of the wafers.
A 100 kV Maskless Ion-Implantation System with an Au–Si–Be Liquid Metal Ion Source for III-V Compound Semiconductors
Authors: Miyauchi Eizo , Arimoto Hiroshi , Hashimoto Hisao , Furuya Tsuneo , Utsumi Takao
Published: November 2005

A newly developed Au–Si–Be liquid metal ion source has been incorporated to a 100 kV focused ion beam system. Among several ion species emitted from the single ion emitter, doubly ionized Si and Be have been selected by the crossed electric and magnetic field (E×B) mass separator and have been formed into a finely focused beam. This new system was found capable of focusing those ions down to a diameter of about 0.1 µm. It has also been found that, using the fine focusing for n- and p-doping, desired ion species (Si++ and Be++) can be exchanged simply by adjusting the electric field of the E×B mass separator.
Surface-Induced Helix-Unwinding Process in Thin Homogeneous Ferroelectric Smectic Cells of DOBAMBC
Authors: Kondo Katsumi , Takezoe Hideo , Fukuda Atsuo , Kuze Eiichi , Flatischler Kurt , Skarp Kent
Published: November 2005

Under conditions where molecules are forced parallel to the cell surfaces but do not orient themselves along a particular direction, we have observed the unwinding process. The cell thickness dependence of the transition temperature from Sm A to distorted Sm C* or Sm C, T
c(d), has been obtained. The apparent tilt angle, θ', has also been obtained as a function of d and T-T
c(d) from two directions giving the darkest view between crossed Nicols. For the 1.6 µm cell, θ' is almost equal to the true tilt angle, θ, at low temperatures but shows a jump from 0° to 9° at T
c. We have qualitatively explained these results in terms of the distortion in the azimuthal angle ϕ of the director, pointing out the importance of its spatial and temporal fluctuations.
Sub-10 ps Logic Operations in Josephson Four-Junction Logic (4JL) Gates
Authors: Nakagawa Hiroshi , Odake Takeshi , Sogawa Eiichi , Takada Susumu , Hayakawa Hisao
Published: November 2005

Sub-10 ps logic delays have been obtained in a Josephson four junction logic (4JL) gate. An experimental circuit including a logic chain of ten 4JL gates whose minimum junction size is 2.5 µm square has been fabricated using a Pb-alloy integration technology. The shortest switching delay has been measured to be 7 ps/gate for the fanout of 1 with a power dissipation of 4 µW/gate.
Superconducting Critical Current Densities of Sputter-Deposited Nb3Ge Films
Authors: Suzuki Mitsumasa , Ōuchi Hiroyuki , Anayama Takeshi
Published: November 2005

Critical current densities J
c of sputter-deposited Nb3Ge films with thicknesses of less than 1 µm have been measured in applied fields either parallel or normal to the film plane. Current densities in the 105 A/cm2 range are obtained in a parallel field of 15 T. A film with the highest J
c consists of regular fine grains of ∼1000 Å in columnar diameter. J
c's of thicker films where A-15 grains with different sizes are observed are relatively low.
Formation of Gallium Nitride at the Interface between Silicon Nitride Encapsulant and Ion Implanted GaAs
Authors: Morita Etsuo , Kawado Seiji
Published: November 2005

GaAs substrates implanted selectively with 100 keV Zn ions to a dose of 5×1014 ions/cm2 were annealed at 700–850°C with an encapsulant of plasma CVD silicon nitride. Transmission electron microscopy revealed that gallium nitride is formed at the interface between the substrate and the encapsulant, and tends to grow epitaxially on (001) (GaAs in the process of 850°C annealing. Gallium nitride was observed in the implanted GaAs area, but not in the unimplanted area. Its formation may be attributable to the presence of the amorphous surface layer produced by ion implantation.
Sn Ion Doping during GaAs MBE with Field Ion Gun
Authors: Bamba Yasuo , Miyauchi Eizo , Kuramoto Kazuo , Takamori Akira , Furuya Tsuneo
Published: November 2005

Low energy Sn ion doping of growing MBE-GaAs at 550°C was made using a liquid metal field ion gun. From Raman measurements, no disordered structures were detected in the grown films. However, the films showed high resistivity and the activation of Sn differed from that of Zn for p-type ion doping previously reported. A broad and weak emission at around 1.28 eV was observed in a photoluminescence spectrum taken at 4.2 K. These suggest that radiation damage caused by Sn ion irradiation remains in the films.
Deep Electron Traps in Undoped Semi-Insulating GaAs Grown by the Liquid Encapsulated Czochralski Method
Authors: Imamura Yoshihiro , Osaka Jiro
Published: November 2005

Semi-insulating undoped GaAs grown by the liquid encapsulated Czochralski (LEC) method has been studied on deep traps using the photocurrent method, Hall effect measurements and thermally stimulated current method. Obvious differences in the photocurrent spectra and the thermal activation energy for carrier density have been observed between crystals grown from Ga rich melt and As rich melt, in spite of either high resistivity or n-type properties. The reason is conceived to be the existence of two kinds of deep trap: approximate levels from the conduction band are 0.72 eV for Ga rich melt, and 0.86 eV for As rich melt.
DLTS Determination of the Mo Acceptor Level in Mo-GaAs0.6P0.4 Schottky Diodes
Authors: Lou J. C. , Lin M. S. , Wan C. P.
Published: November 2005

The results of deep level transient spectroscopy (DLTS) and Auger electron spectroscopy (AES) have shown the correlation between the trap levels, existing in the metal-semiconductor interface or in the bulk of these thermally degraded Mo-GaAs0.6P0.4 Schottky diodes, and the metal-semiconductor interdiffusion. These trap levels will enhance the generation-recombination effect and degrade the diode performance. From the experimental results, it reveals that the Mo-indifiusion induced hole trap Ev+(0.83±0.01) eV plays a major role in Mo–GaAs0.6P0.4 Schottky diode degradation.
Wavelength Demultiplexing Photodiode with Very High Isolation Ratio
Authors: Sakai Shiro , Umeno Masayoshi
Published: November 2005

A new wavelength demultiplexing photodiode that utilizes Bragg reflector composed of multi-thin crystal is proposed and its quantum efficiency and optical cross talk are calculated. It is shown that significant improvement in crosstalk can be obtained by the proposed structure without lowering the quantum efficiencies at the signal wavelengths.
Oxygen-Related Defects in Irradiated Germanium
Authors: Fukuoka Noboru , Saito Haruo , Kambe Yoshiyuki
Published: November 2005

Oxygen-related defects produced in oxygen-doped germanium by 1.5 MeV electron irradiation were studied by DLTS technique. Three electron trapping levels attributable to this type of defect were found.
The E
c-0.25 eV level is deduced to be introduced by two kinds of defects, namely, the germanium A-center (oxygen-vacancy complex) and the defect associated with the 715 cm-1 infrared absorption band reported by Whan. The E
c-0.29 eV level and the E
c- 0.13 eV level are attributable to the defects associated with the 819 cm-1 and the 731 cm-1 infrared absorption bands in her paper.
Pair and Quasiparticle Tunnelings in Arrays of SIS Junctions Observed by Radio Frequency Noise
Authors: Hayashi Yoshikazu , Kobayashi Masayoshi , Sakai Kiyomi , Noguchi Takashi
Published: November 2005

The influence of 35 GHz microwave radiation on the radio frequency (10 MHz∼500 MHz) noise in arrays of superconductor-insulator-superconductor (SIS) junction is investigated. Intensities of noise outputs show structures with voltage scales of 2hν/e for two junction arrays, and 10hν/2e for ten junction arrays which indicate that both the quasiparticle and the pair electron tunnelings occur in these arrays.
Transmission Electron Microscopy of Monatomic Surface Layers
Authors: Takayanagi Kunio
Published: November 2005

Surfaces of (111)Ag platelets prepared by vacuum deposition in situ in an ultra-high-vacuum electron microscope are investigated. Monatomic high terraces, which nucleate and grow one after another by Ag deposition, show distinct contrast between them in the dark field images of the (01,1)hex reflection of 1∼1.5. Imaging of monatomic surface layers by surface reflection is discussed in comparison with that by bulk forbidden reflection.
Study of Two Different Deep Levels in Undoped LEC SI–GaAs by Photoluminescence Spectroscopy
Authors: Kikuta Toshio , Terashima Kazutaka , Ishida Koichi
Published: November 2005

Undoped LEC SI–GaAs crystals can be classified into two groups with respect to the deep PL emission band. One group dominantly exhibits emission peak energy at 0.8 eV, and the other at 0.65 eV. The profile along the growth direction and the wafer diameter for resistivity was similar to that for the 0.8 eV PL peak intensity in the 0.8 eV dominant crystals, while it was opposite to that for the 0.65 eV PL peak intensity in the 0.65 eV dominant crystals. The presence of these emission bands was found to depend on the growth conditions. Results suggest that two deep levels related to different origins are present in undoped LEC SI–GaAs.
Reentrant Distorted Sm C* Observed under Electric Field in Ferroelectric Smectic Liquid Crystals, nOBAMBC
Authors: Kondo Katsumi , Takezoe Hideo , Fukuda Atsuo , Kuze Eiichi
Published: November 2005

By using a partially degraded cell possessing T
c gradient, we have visualized in a micrograph reentrant distorted Sm C* under an electric field; the fringe disappears in the middle where T
c-T∼0.25°C but can remain near the T
c position. The E-T diagram thus obtained is different from that predicted by Michelson et al. and is explained by the effect of the tilt angle fluctuation. We have also found that, when the cell quality is not high, there appears a blue color in the vicinity of T
c, though we could not clarify the cause of its appearance.
A Study of the Anomalous Transmission (Borrmann Effect) for Obliquely Incident Light in an Absorbing Single-Domain Cholesterie Liquid Crystal
Authors: Endo Shyunsuke , Kuribara Tadashi , Akahane Tadashi
Published: November 2005

The Borrmann effect for obliquely incident light is qualitatively explained using the Optical Eigen Modes. Transmission spectra from an absorbing single-domain cholesteric liquid crystal are measured for obliquely incident light. The Borrmann effect is still found to be in exitence at a small angle of incidence. The transmission spectra at a large angle of incidence, however, show that the Borrmann effect has disappeared. Transmission spectra are numerically calculated by the 4×4 matrix method and are in good agreement with the experiments.