bluuebunny/crossref_metadata_2025 huggingface dataset:
Wave-Optical Property of Undulator Radiation and Its Effect on Grating Monochromators
Authors: Miyahara Tsuneaki
Published: November 2005

The wave-optical description of undulator radiation is presented based on a virtual grating model. It is shown that the optical emittance of the coherent part of the radiation is roughly equal to the minimum emittance defined by the uncertainty principle of light. Some discussion is presented about the emittance matching between undulator radiation and grating monochromators.
Influence of molecular Gases on the Output characteristics of a Copper Vapor Laser
Authors: Huang Zhen-Guo , Namba Kazumi , Shimizu Fujio
Published: November 2005

The effect of molecular gas impurities in the Ne buffer gas on the output characteristics of a copper-vapor laser has been investigated. Molecules with hydrogen atoms are found to increase the laser output power and improve the intensity distribution over the cross section of the beam. Hydrogen improves the average output power by as much as 50% and the efficiency by 60%. A maximum average power of 27 W is obtained using the plasma tube with a 32 mmφ×70 cm active volume.
Measurement of Particle Size Using the Dual-Beam Laser Interferometer with the Receiving Optics Composed of the Array of Fiber-Bundles
Authors: Takeo Takashi , Hattori Hajime
Published: November 2005

How to apply an array of fiber-bundles to the receiving optics of a dual-beam laser interferometer was investigated regarding the measurement of particle size. An aperture construction with fiber-bundles enabled us to apply the interferometer to particle-sizing in narrow spaces owing to the flexibility and the fineness of optical fibers. It was also possible to adjust the “measurable range” of the visibility curve to the desired range of particle size by selecting the appropriate fiber-bundle or bundles from the array. Signal visibility was calculated by ray-tracing and measurement errors caused by oscillating components in visibility curves are discussed. Measured results for glass beads are also presented in order to confirm the analyses. Close agreements between the calculated and measured results were obtained.
Microwave Simulation of Reflection and Scattering by Pits on Optical Disks
Authors: Horita Motoshi , Miyazaki Yasumitsu
Published: November 2005

The Simulation of scattered far-field patterns by three-dimensional models of pits on brass plates were carried out using a microwave beam with a frequency of 50 GHz. The dependence of the scattered field patterns on the pit form, depth and size were examined. They were almost independent of the pit aperture forms (for example, circular, square and rectangular) with the same area. The power level of the main lobe corresponding to specular reflection became a minimum at a pit depth of h\fallingdotseq0.3 λ, where λ is the microwave wavelength, and an aperture size of a\fallingdotseq0.8 σ, where σ is the beam width. Simultaneously, the levels of the side lobes were at a maximum. The measured fields of the main lobe were in good agreement with those calculated using the Kirchhoff approximation.
Forced Rayleigh Scattering in nCB's (n=5-9) with Methyl Red and Binary Mass Diffusion Constants
Authors: Hara Masahiko , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

Binary mass diffusion constants of methyl red in nCB's (n=5-9) were measured by forced Rayleigh scattering. It was found that the diffusion constants in nCB's with odd carbon atoms in the alkyl chain are larger than those with even ones. This odd-even effect could be explained by the molecular structural anisotropy, which is mainly governed by the alkyl chain length. The origin of the transient grating in liquid crystalline phases is attributed to the periodic structure of an order parameter. An anomalous increase in the diffraction efficiency was observed as the phase-transition temperature was approached. This phenomenon could be interpreted as a photostimulated change in the phase transition temperature proposed by Odulov et al.
Structure of the Natural Oxide of Amorphous Silicon
Authors: Ohsaki Hisashi , Miura Kouji , Tatsumi Yukichi , Ino Tadashi
Published: November 2005

The structure of the natural oxide, which is produced in air at room temperature, of amorphous silicon has been investigated using high-energy electron diffraction. From a least-sequares analysis of the reduced radial distribution functions, three atomic distances of the oxide were found to be 1.63, 2.85 and 3.2 Å besides Si-Si bond length of 2.37 Å. The structure of the oxide can not be the SiO4-tetrahedron, since the first and second distances cannot be explained by a tetrahedron arrangement. As the first and second distances can be considered the Si-O bond and O-O atomic distances, respectively, the average O-Si-O angle is about 122°, larger than that of the SiO4-tetrahedron.
Ellipsometric Study of Nb-Al-AlOx Layered Structure for All-Refractory Josephson Junctions
Authors: Tanabe Keiichi , Asano Hidefumi , Michikami Osamu
Published: November 2005

The deposition of an ultra-thin Al overlayer on Nb thin films and its thermal oxidation were observed by in-situ ellipsometry. All-Nb tunnel junctions were fabricated using these Nb-Al bilayers and their tunneling characteristics were compared with the ellipsometric results. The ellipsometric parameters of the bilayers are sensitive to Al diffusion into the Nb grain boundaries, and show that the extent of the diffusion largely depends on the cooling interval between the Nb and Al depositions, that is, the substrate surface temperature. The wide range of parameters and the changes in the junction tunnel characteristics observed are systematically explained assuming a trilayer (the base Nb film, the Al-diffused layer and the residual Al layer) model. The thicknesses of the latter two layers can also be semiquantitatively determined from the calculations based on this model.
Direct Writing of Silicon Lines by Pyrolytic Argon Laser CVD
Authors: Ishizu Akira , Inoue Yasuo , Nishimura Tadashi , Akasaka Yoichi , Miki Hidejiro
Published: November 2005

A novel laser-induced CVD apparatus with a direct pattern writing ability by a pyrolytic decomposition of SiH4 has been developed. With this equipment, a CW argon laser with an output power of 20 W was used. The argon laser beam, which provides localized heating of the substrate, was utilized to decompose gas-phase molecules, resulting in film deposition. By using this equipment, direct pattern writing of polycrystalline silicon with a smooth surface on silicon substrate covered with SiO2 layer has been realized with a high deposition rate as well as good controllability and crystallinity.
Determination of Lattice Distortion in (GaAs)28(AlAs)24 Superlattice Layers by X-Ray Diffraction
Authors: Kashihara Yasuharu , Kase Tomohiro , Harada Jimpei
Published: November 2005

The structure of a (GaAs)28(AlAs)24 superlattice grown by MBE has been characterized in detail by X-ray diffraction. By applying a new method of Fourier analysis (Harada et al.: Jpn. J. Appl. Phys. 24 (1985) L62), both the concentration and lattice distortion modulations existing in the multilayer were determined on the basis of the integrated intensities of the satellite reflections around the (400) fundamental Bragg reflection. Both modulations were found to be like a step function. It is pointed out that the width of the boundary between the two regions should be narrow and less than two intermolecular layers. The spacings between successive cation layers were 2.827 and 2.835 Å in the regions of GaAs and AlAl, respectively, along the (001) direction. This is in good agreement with the values calculated from the Poisson expansion model.
Annealing Behavior of Amorphous C:H Films Prepared by Glow Discharge Decomposition of CH4 and H2
Authors: Watanabe Ichiro , Okumura Toshiyuki
Published: November 2005

Hydrogenated amorphous carbon films with high contents of sp3 bonds have been prepared by a glow-discharge-decomposition of CH4 and H2 mixture. The film thickness and the optical gap of the films were gradually reduce up to annealing at 350°C by the densification of the film; they rapidly reduce above 350°C. The hydrogen density in the films, however, was almost constant. From the variation of mass spectra with annealing, the decomposition of the films was found to begin at 350°C, accompanied by a volatilization of various forms of hydrocarbon such as CH
n
, C2H
n
and C3H
n
.
Thermal Stability of Hg1-xCdxTe Crystals Covered with the Anodic Oxide Films
Authors: Takita Kôki , Ippōshi Takashi , Murakami Kouichi , Masuda Kohzoh , Kudo Hiroshi , Seki Seiji
Published: November 2005

Hg loss from the near-surface region of Hg1-x
Cd
x
Te with and without anodic oxide caps by a 60-min heat-treatment has been estimated for x≃0.2 and x≃0.3 from 40-MeV-O5+ backscattering spectra. The Hg loss rate for various heat-treatment temperatures T was compared with the T-dependence of the Hg content of the oxide films. For x≃0.2, the Hg loss of a sample with 1000 Å oxide film exceeded 1×1017 Hg/cm2 at T>300°C, while that of the uncapped sample reached the same level around T=250°C. For x≃0.3, the Hg loss was not appreciable up to 320°C, even for an uncapped sample; however, it exceeded 1×1017 Hg/cm2 around T=340°C, even for a capped sample. Furthermore, the Hg content of anodic oxide films rapidly decreased in the temperature range 250∼290°C for both x≃0.2 and x≃0.3. These behaviours suggest that protective effect of the oxide cap against Hg loss decreases with decreasing Hg-content of the films.
Decrease in Electrical Resistivity of W Films on GaAs Substrates after High-Temperature Annealing
Authors: Ohfuji Shin-ichi , Kuriyama Youichi , Nagano Jin
Published: November 2005

A specific decrease in the electrical resistivity of W films on GaAs substrates was found after annealing above 800°C in Ar. A decrease in the concentration of oxygen in sputter-deposited W films (0.2 µm thick) with a diffusion of Ga and As atoms from GaAs substrates into the films was also observed after annealing using AES and SIMS measurements. The decrease in the resistivity could be explained by a remarkable W grain growth by applying the Mayadas and Shatzkes grain boundary scattering theory. The grain growth was accompanied by the release of oxygen from the films. Depth-distribution profiles of Ga, As, and O in W/GaAs structures suggest two processes for the release. One is a pile-up of the oxygen which forms Ga-oxide on a W film surface. The other is the evaporation of oxygen from the surface in the form of As-oxide.
Binding Energies of Wannier Excitons in Ga1-xAlxAs Quantum-Well Wires
Authors: Kodama Takeshi , Osaka Yukio
Published: November 2005

Binding energies of Wannier excitons in a quantum-well wire consisting of a single wire of GaAs embedded in Ga1-x
Al
x
As were calculated using a variational approach. The variations of the binding energies of the heavy and light hole excitons as a function of the width of the GaAs quantum-well wires for various values of the heights of the potential barrier were calculated and their behavior is discussed.
Some Considerations Regarding the Performance of High-Pressure Vapor Discharge Lamps
Authors: Takahashi Kunihiko
Published: November 2005

Considerations were made concerning the starting voltage (V
s) and the temperature-vapor pressure characteristics for high-pressure vapor discharge lamps, e.g. high-pressure sodium lamps or metal halide lamps. It was found that this V
s corresponds to the wave function in quantum mechanics, and that there is an optimum pressure at which the luminous efficacy of the lamp assumes a maximum value.
Laser Patterning Method for Integrated Type a-Si Solar Cell Submodules
Authors: Nakano Shoichi , Matsuoka Tsugufumi , Kiyama Seiichi , Kawata Hiroshi , Nakamura Noboru , Nakashima Yukio , Tsuda Shinya , Nishiwaki Hidenori , Ohnishi Michitoshi , Nagaoka Isao , Kuwano Yukinori
Published: November 2005

A laser patterning method was investigated as a fabrication method for integrated-type amorphous-silicon (a-Si) solar cell submodules. A three-dimensional thermal analysis of a multilayer structure was performed to determine the selective scribing conditions for each layer of an a-Si solar cell. The optimum laser power densities calculated from a three-dimensional thermal analysis were confirmed by the experiments. It was found that not only transparent conductive oxide and a-Si films, but also the metal electrodes of the integrated-type a-Si solar cell submodule were selectively scribed.
The total output power of an a-Si solar cell submodule patterned by optimum laser-power densities was 9% higher than that achieved by a conventional patterning method.
Excimer Laser Photochemical Directional Etching of Phosphorous Doped Poly-Crystalline Silicon
Authors: Sekine Makoto , Okano Haruo , Horiike Yasuhiro
Published: November 2005

Photochemical anisotropic etching of a gate material for MOS devices (n
+ poly-Si) has been investigated, based on the Reactive Ion Etching (RIE) mechanism. By adding deposition gas to the etching gas (chlorine), a thin organic film can be formed for preventing chlorine atoms from reacting on the sidewalls of fine patterns. Simultaneously, a normally irradiated laser beam removes the film at the bottom surface and promotes an etching reaction. Thus, directional etched features can be achieved. Also, radiation damage can be evaluated in comparison with RIE. The photochemical etching technique is one of most suitable processes for future MOS devices without radiation damage.
GaAlAs/GaAs TJS Lasers on Si Substrates Operating at Room Temperature Fabricated by MOCVD
Authors: Sakai Shiro , Hu Xiong Wei , Soga Tetsuo , Umeno Masayoshi
Published: November 2005

GaAlAs/GaAs TJS (transverse junction stripe) laser diodes were fabricated on p-Si substrates using strained super lattice intermediate layers. The diodes have lased at room temperature (27°C) pulsed conditions. The lowest threshold current is 379 mA.
Space-Charge-Limited Currents in Insulators with Nonuniform Spatial Distribution of Shallow Traps
Authors: Koda Norio
Published: November 2005

Current-voltage (J-V) characteristics in insulators with a nonuniform spatial distribution of traps are derived using the regional approximation method. The J-V curves are shown to possess asymmetry (rectification). The cause of this effect is explained as resulting from the difference in the voltage distribution in an insulator according to the bias conditions.
Method of Analysis of a Single-Peak DLTS spectrum with Two Overlapping Deep-Trap Responses
Authors: Nakashima Hiroshi , Miyagawa Tsuyoshi , Sugitani Suehiro , Hashimoto Kimio
Published: November 2005

In the usual DLTS technique, the trap activation energy is obtained from Arrhenius plots of the inverse of time constants set up experimentally vs the inverse peak temperatures of the DLTS signals. Considerable error, however, may appear in the activation energy when DLTS singals with a hump or shoulder are observed. In a special case, a single-peak DLTS is obtained when the signals due to two or more individual traps overlap. However, it is possible in this case to separate each deep-trap response from the overlapping DLTS signal by observing the injection pulse width dependence of the transient capacitance, and to determine the trap parameters such as the activation energy correctly. This paper presents a method for determining the trap parameters from the injection pulse width dependence of the DLTS spectrum.
Low-Threshold InGaAsP-InP Metal-Clad Ridge-Waveguide (MCRW) Lasers for 1.3 µm Wavelength
Authors: Amann Markus-Christian , Stegmüller Bernhard
Published: November 2005

Metal-clad ridge-waveguide (MCRW) lasers have been prepared in InGaAsP-InP for 1.3 µm wavelength by liquid-phase epitaxy. CW threshold currents as low as 28 mA and efficiencies above 0.25 mW/mA per facet are achieved. Lasers with 2-3 µm wide stripes show stable operation in the fundamental lateral mode and linear light-current characteristics up to more than 10 mW. The maximum temperature for CW operation of upside-down mounted devices is 75°C.
Optical and Thermal Ionization of Iron-Related Defects in Silicon
Authors: Nakashima Kenshiro , Chijiiwa Masahiro
Published: November 2005

The optical and thermal ionization energies of several Fe-related defects in Fe-diffused Si are determined simultaneously using the photostimulated capacitance transient method together with deep-level transient spectroscopy. Two defect states with thermal electron-ionization energies of 0.36 and 0.56 eV to the conduction band, respectively, are confirmed to originate from the Fe-related defects, in addition to the donor level due to interstitial Fe. The origins of these defects are discussed on the basis of their behaviors in n- and p-type Si.
Smoothing of Nonuniformity by X-ray Radiation in Cannonball Target
Authors: Murakami Masakatsu , Nishihara Katsunobu
Published: November 2005

The geometrical smoothing effect of X-ray radiation propagating through a cavity between the tamper and the pusher in a cannonball target was investigated as a function of the pusher radius, and the maximum pusher radius required to obtain a density compression rate of 1000 was estimated. The reduction of the growth of Rayleigh-Taylor instability by the smoothing effect is discussed. The results are applied to the GEKKO XII and GEKKO MII laser systems.
Nanosecond Calibration Light Source Using LED for Ruby-Laser Thomson Scattering Device
Authors: Yamauchi Toshihiko , Yanagisawa Ichiro
Published: November 2005

A nanosecond LED ligh pulse similar to the ruby laser light was used to calibrate a ruby laser Thomson scattering device.
The continuous spectral region between 5500Å and 7000 Å was obtained using two different kinds of LED element. The calibration data was obtained within 1-2% fluctuation in the repeated experiments, and the uncertainty in the relative sensitivity calibration constant was below 2%. The following results were obtained using the nanosecond light source: The width of the light pulse was scarcely changed during the pulse's passage through the optics and electronics. The transmission time from entering the fiber optic system to entring the data acquisition system was determined in order to minimize the gate duration.
Calculation of High-Resolution Electron Microscopic Images of Crystalline Embryos in Amorphous Metals
Authors: Hamada Tadashi , Fujita Francisco Eiichi
Published: November 2005

Recent high-resolution electron microscopy (HREM) of amorphous alloys has revealed that, under the condition of axial illumination, lattice-like fringes or dots frequently appear even in as-quenched samples. These could arise from the medium-range order in the atomic arrangement in the amorphous structure expected from the authors' theoretical prediction and diffraction calculations based on the crystalline embryo model. In this paper, a computer simulation of HREM images from a thin film of amorphous alloy is carried out using the embryo model. By choosing appropriate values for the spherical aberration constant and defocus distance, lattice-like fringes and dots with spacings of about 2 A extending over 10 A in diameter are well reproduced. The variations, overlapping, and frequency of appearance of the images are also calculated and are compared with the experimental results.
Critical Current Density of Superconducting Nb-Ta in the Longitudinal Magnetic Field
Authors: Kikitsu Akira , Hasegawa Yasuyuki , Matsushita Teruo
Published: November 2005

A nondissipative current carried in a type-II superconductor in the longitudinal magnetic field is known to be caused by the flux-pinning interaction, as is the current in the transverse magnetic field. However, only a few systematic experiments on the critical current density under the longitudinal magnetic field have been investigated from the viewpoint of flux-pinning.
This paper reports the critical current density of Nb-Ta specimens measured as a function of the pinning strength in the longitudinal or transverse field. The longitudinal critical current density was found to depend strongly on the pinning strength. The result is compared qualitatively with the transverse critical current density from the viewpoint of the summation of the flux-pinning interactions.
Coupling-Current Loss in a Multifilamentary Superconducting Wire Subjected to a Transverse AC Magnetic Field with a Relatively High Sweep Rate
Authors: Noda Minoru , Funaki Kazuo , Sumiyoshi Fumio , Miyahara Kuniyuki , Yamafuji Kaoru
Published: November 2005

The electromagnetic behavior of a multifilamentary superconducting wire subjected to an external transverse AC magnetic field with a trapezoidal wave form is discussed analytically with the aid of the so-called continuum model. The present expression for the coupling-current loss agrees well with the experimental results reported by Zenkevitch et al. for a practically important range of the sweep rate, whereas the present expression is only an approximate one with a quite simple form. The effects of the presence of a transport current on the coupling-current loss are also discussed analytically. The present analytical method can also reproduce the numerical results on the radius of the internal region and the shape of the saturated region presented by Rem et al. and Ciazynski et al. fairly well up to a relatively high sweep rate of the external magnetic field.
Carrier Concentration and Thickness Measurements of n-Type GaAs Epitaxial Layer by Cell Voltage in Anodization
Authors: Masaki Kazuo , Miyamoto Shunsuke
Published: November 2005

The carrier concentration and thickness of n-type GaAs epitaxial layers were obtained by cell voltage measurements in anodization, and the results are compared with those obtained by differential C-V measurements. The carrier concentrations in the epi-layer are within the order of those obtained by C-V measurements and the thicknesses of the epi-layer agree with those obtained by C-V measurements. The technique described here enables the carrier concentration and thickness of an epi-layer such as n on an n+ substrate to be determined simply and inexpensively.
Preparation of Long Filaments of Superconducting Pb-Bi-Te Alloy with High Tc by Glass-Coated Melt Spinning Method
Authors: Gotō Tomoko , Hayashi Minoru
Published: November 2005

The melt spinning of a Pb-Bi-Te system alloy with Pyrex glass was investigated as a means of producing a superconducting long filament with high T
c. Long filaments with T
c higher than 10 K, having a mixed structure of the ε-phase, the bismuth phase and the tellurium phase were obtained from the molten state at 1500 K with a winding speed of 2.63 m/s. For example, a Pb45Bi40Te15 filament with T
c of 10.2 K was 24 µm in diameter and was a ductile material with a tensile strength of 29 MPa and an elongation of 3.1%. A filament annealed at 573 K for 600 s had a high T
c of 9.7 K and a high strength of 20 MPa. Severe heat treatment did not cause the growth of crystal grains of size 2000 Å. The lead, bismuth and tellurium were distributed homogeneously in the filament. The interface between the tellurium and the ε-phase is considered to play an important role in the enhanced T
c.
Phase Segregation of Polyether-Polyamide Copolymer PEBAX by Thermally Stimulated Current Method
Authors: Faruque H. S. , Lacabanne C.
Published: November 2005

The glass transition β of polyamide 12 (PA12, M̄
n= 830) and polytetramethylene glycol (PTMG, M̄

n
= 2000) has been observed at 43°C and -74°C respectively by thermally stimulated current (TSC) method. The copolymer poly(ether block amide), PEBAX having hard segment PA12 (M̄
n= 898) and soft segment PTMG (M̄
n= 2032) has been studied by TSC. The respective peaks of PTMG and PA12 are located at -69.5°C and 13.5°C for a raw material sample and -70°C and 9°C when the sample is recrystallised after melting showing the presence of two defined phases in this system. The effect of slow cooling after polarisation on the hard segment has been observed. The influence of viscosity on the phases polytetramethylene glycol βPTMG and polyamide 12 βPA has been investigated. Activation energy and relaxation times have been calculated for βPTMG and βPA relaxations by the fractional polarisation method. Two phases are also identified.
Deep Defect Levels in Plastically Deformed GaAs
Authors: Suezawa Masashi , Sumino Koji
Published: November 2005

Defect states in plastically deformed GaAs are investigated by means of the Hall effect, photo-ESR and photoluminescence. A high concentration of acceptors is generated in GaAs as a result of plastic deformation. ESR-active centers giving rise to a signal consisting of four isotropic absorption lines are introduced by both plastic deformation and electron-irradiation. The energy of photo-activation of unpaired electrons from such centers to the conduction band is about 0.8 eV. Defects related to such centers induced by deformation or electron-irradiation are different from grown-in ESR-active centers and are concluded to be As atoms on tetrahedral interstitial sites each surrounded by four Ga atoms. A broad photoluminescence line is developed at 1.13 eV in plastically deformed GaAs but not in electron-irradiated GaAs. This line is thought to be related to the radiative recombination occurring at β dislocations.
Geometrical Correction Factor for Resistivity of Semiconductors by the Square Four-Point Probe Method
Authors: Yamashita Masato
Published: November 2005

The geometrical correction factor for the resistivity of semiconductors is derived for a system consisting of a square four-point probe array on a rectangular parallelepied. The van der Pauw method requires the geometrical correction factor for samples with a thickness greater than about 35% of the probe separation. Numerical evaluations are given as a function of the size of the rectangular parallelepiped and the probe configuration.
Effect of Alloy Scattering on Electron and Hole Impact Ionization Rates in Ga1-xInxAsyP1-y Alloy System
Authors: Osaka Fukunobu , Mikawa Takashi , Wada Osamu
Published: November 2005

The effect of alloy scattering on the electron and hole impact ionization rates, α and β in the Ga1-x
In
x
As
y
P1-y
alloy system lattice-matched to InP substrates is analyzed. A Monte Carlo simulation shows that the experimental α and β values in GaInAsP are very well explained by introducing alloy scattering, which greatly reduces α and β in the alloy system.
This indicates that alloy scattering must be taken into account in estimating or deriving ionization rates in an alloy semiconductor.
Photoconduction Mechanism of Amorphous Selenium: Effect of Surface Recombination
Authors: Isobe Toshifumi , Kobayashi Shunsuke , Kiwaki Hisatomo
Published: November 2005

The drop in quantum efficiency of the photo-carrier generation in amorphous selenium at low applied electric fields (<5×105 V/m) is explained theoretically, using Onsager's theory and taking account of surface recombination.
Temperature and Wavelength Dependence of the Fluorescence Lifetime of Anthracene Crystals
Authors: Ahmad-bitar Riyad N. , Bulos Basim R. , Hassan Isam R. , Jomah Mahmud H.
Published: November 2005

The effect of temperature (from 10 K to 300 K), crystal thickness, and fluorescence wavelength (at 10 and 300 K), on fluoresence lifetime for anthracene single crystal is studied. The effect was attributed to 1) reabsorption due to change of lifetime with thickness and 2) two guest fluorescing levels in thermal equilibriumn with the singlet exciton. This is in agreement with some of the reported results. The effect of fluorescence wavelength was interpreted in terms of the suggested time dependent reabsorption model. This model has been confirmed with the results obtained at two different temperatures.
Experiments on the Energy Distribution Function in Hydrogen Plasmas
Authors: Amemiya Hiroshi
Published: November 2005

The electron energy distribution function has been measured in typical hydrogen plasmas in a multipole plasma device by an improved alternating-current probe method. The function is found to be non-Maxwellian, containing primary electrons, thermal electrons and groups due to inelastic scattering of the primaries.
A characteristic peak due to negative ions in the distribution has been detected and is used to determine the density of negative hydrogen ions. The variations of their density with the densities of thermal electrons and primary electrons have been studied and interpreted.
The dependence of the relative intensity of the negative ion peak on the probe material, probe shape, and frequency of the superimposed ac signal has been investigated. The optimum conditions have been determined for using the probe method to measure the negative ion density in plasmas.
Equilibrium Plasma Control for a Large Tokamak with Many Poloidal Coils to Produce the Ohmic and Equilibrium Field
Authors: Kinoshita Shigeyoshi , Yoshioka Ken , Kobayashi Tomofumi
Published: November 2005

Plasma equilibrium control methods, based on a multivariable control technique, are formulated in the hybrid poloidal coil system, where all of the many coils are designed for ohmic heating and controlling the plasma equilibria of a large tokamak. This formulation is divided into a program control method during the buildup phase and a feedback method for controlling the plasma current and the equilibrium during the steady-state phase. The former gives programming coil currents and voltages in order to reduce the required peak power by adjusting the magnetic field profile inside the plasma, keeping the plasma equilibrium fixed. The latter includes a proportional-integral (PI) control law in the conventional optimal control theory. Effective plasma equilibrium control by these methods was obtained in computer simulations for a fusion reactor with a major radius of 5.5 m.
Nuclear Analysis of GEKKO XII ICF Experiment Facility
Authors: Tsuji Ryusuke , Ido Shunji , Deguchi Yuuji , Yamanaka Masanobu , Yamanaka Tatsuhiko , Yamanaka Chiyoe
Published: November 2005

This paper reports a nuclear analysis of the neutrons from a DT pellet measured in inertial confinement fusion experiments in the GEKKO XII glass laser system. The items discussed are the neutron energy spectrum from a pellet and the outside of the chamber wall, the neutron leakage fraction through the wall and the windows of the chamber, the induced radioactivity of the activation test pieces, and the effects of these on the neutron measurements. The dose due to the fusion neutrons and γ-rays and the induced radioactivity is also described.
Orientation Dependence of Lateral Solid-Phase-Epitaxial Growth in Amorphous Si Films
Authors: Yamamoto Hiroshi , Ishiwara Hiroshi , Furukawa Seijiro
Published: November 2005

The characteristics of the lateral solid-phase-epitaxial (L-SPE) growth of undoped and P-doped amorphous Si (a-Si) films on SiO2 patterns formed in various directions on (100) and (110)Si substrates were investigated. It was found that (1) the L-SPE growth length becomes a minimum in directions such that {111} facet planes can be formed parallel to the SiO2 pattern edge and (2) the growth rates in these directions are constant. It was also found that the growth rates in other directions are faster in the initial stages of L-SPE, but decrease with the annealing time and reach the same saturated value as the above constant rate. The L-SPE growth rates were also compared with the growth rate of polycrystalline grains in P-doped a-Si films.
Tungsten Photochemical Vapor Deposition Mechanism in WF6+H2 System I. Adspecies Excitation Model
Authors: Toyama Masaharu , Itoh Hitoshi , Moriya Takahiko
Published: November 2005

The tungsten film deposition rate in the WF6+H2 system increases in proportion to the reaction time under light irradiation, while it remains constant in thermal deposition. This phenomenon is analyzed kinetically on the basis of the adspecies excitation model. Light is assumed to suppress adsorption but to enhance desorption, and to promote the excitation of adspecies. The rate equations are solved analytically without assuming steady states. The deposition rate obtained reproduces the observed time-dependence for both thermal and photochemical processes, though qualitatively. One difficulty still remains with this model, and a guideline for resolving it is presented.
Dependence of Warpage of Czochralski-Grown Silicon Wafers on Oxygen Concentration and Its Application to MOS Image-Sensor Device
Authors: Shimizu Hirofumi , Fujita Masato , Aoshima Takaaki , Sugino Yuji
Published: November 2005

The resistance of precipitation-treated Czochralski-grown silicon wafers to warpage has been investigated using crystals containing oxygen at a concentration of 5.5-12.3×1017 atoms/cm3. The precipitation softening is effectively suppressed if the oxygen concentration is lower than a threshold value of about 8×1017 atoms/cm3. In wafers with oxygen concentrations of 5.5-8×1017 atoms/cm3, oxygen precipitation proceeds slowly, resulting in slow growth of bulk stacking faults and few dislocation sources. In MOS image-sensor devices, the wafers with such oxygen concentrations have few crystal defects within the area of the photodiodes after processing, which cause the fatal failure of white blemishes detected as white scratches on output pictures.
Tungsten Photochemical Vapor Deposition Mechanism in WF6+H2 System II. Gas-Molecule Adspecies Collision Model
Authors: Toyama Masaharu , Itoh Hitoshi , Moriya Takahiko
Published: November 2005

Two new models are proposed for the W photochemical vapor deposition mechanism; one is the gas-phase intermediate formation model and the other is the gas-molecule adspecies collision (GAC) model. The GAC model, a modification of the adspecies excitation model proposed in a previous paper, is the most promising. A collision term between an excited WF6 gas molecule and an intermediate M adsorbed on the W surface is added to the decomposition of M. This collision reaction is dominant under light irradiation. It produces a W atom and a new intermediate M and does not limit the time constant of the intermediate concentration. The new model completely reproduces the observed time and light-intensity dependences of the W deposition rate.
ZnS:Mn Electroluminescent Device Prepared by Metal-Organic Chemical Vapor Deposition
Authors: Hirabayashi Katsuhiko , Kozawaguchi Haruki
Published: November 2005

AC thin-film ZnS:Mn electroluminescent devices were fabricated by metal-organic chemical vapor deposition, using dimethylzinc and H2S as source gases and tri-carbonyl-methyl-cyclopentadienyl-Mn as the dopant gas. Tri-carbonyl-methyl-cyclopentadienyl-Mn was decomposed by heating at 580°C at the entrance of the reactor, enabling the ZnS film to be doped homogeneously with the optimum concentration of Mn. The brightness of metal/insulator/semiconductor electroluminescent devices made with the resulting ZnS:Mn film was more than 5000 cd/m2 (5 kHz, 130 V), while metal/insulator/semiconductor/insulator electroluminescent devices had a brightness of more than 6000 cd/m2 (5 kHz, 160 V) and exhibited hysteresis in their brightness-voltage characteristics.
Behavior of Plasma Produced by a Long CO2-Laser Pulse in a Spindle-Cusp
Authors: Ogasawara Munehiro , Seki Hirohumi , Sekiguchi Tadashi , Yaji Tsuyoshi , Kohno Tetsushi
Published: November 2005

A plasma was generated at the null-field center of a spindle-cusp magnetic container by using a high-power CO2-laser beam with a relatively long pulse duration (∼2 µs) and a beryllium thin-wire laser target, and the behavior of the plasma thus produced was studied, concentrating on its high-beta (β∼1) confinement phase. The experimental results indicate that 1) a cusp plasma with β>0.5 resides for longer than 1.5 µs, 2) the particle-loss aperture size of a ring-cusp (w
r; FWHM) in the high-β regime is near the local ion Larmor diameter (2a
i) for non-thermalized high-energy ions initially, and this tendency persists even in the later low-β time region, where the w
r-value is nearly equal to the local 2a
i-value for thermalized low-energy ions. In view of the observation that the magnitude of the ion loss flux is not inversely proportional to the magnetic field strength in the high-beta regime, a scaling for the cusp particle confinement time (τ) is derived by an extension of existing theories. The expected theoretical τ-value does not deviate greatly from that estimated from the experimental observation.
Phase Transition of Lipid Multilamellar Aqueous Suspension under High Pressure III. Laser Raman Spectroscopic Study of Dipalmitoyl Phosphatidylcholine Bimembrane under High Pressure
Authors: Utoh Shigenori , Takemura Tetuo
Published: November 2005

The vibrational Raman spectra of a model bimembrane (DPPC) was used to probe its structural characteristics in the respective phases under high pressure. The frequency shift, band width and relative peak height (containing both intrachain and inter-chain order parameters) of the respective Raman bands were measured as a function of temperature with the following results: the structure below the 4th-transition temperature is reconfirmed as orthorhombic PE-type packing with all-trans chains. At the 4th-transition point, intra-chain and inter-chain disorderings clearly occur. Around the sub-transition, abnormality of the Raman spectra accompanied by a movement of the head group equivalent to a melting-like behavior (observed by WAXS) occurs. Above about 2.5 kbar (the tricritical point) in the pre-transition line, continuous structural changes are observed as the temperature increases through the pre-point in place of the discontinuous changes observed below about 2.5 kbar.
Equilibrium Potential and Exchange Current Density of Metal Hydride Electrode
Authors: Yayama Hideki , Hirakawa Kazuyoshi , Tomokiyo Akihisa
Published: November 2005

The equilibrium potential and exchange current density were measured as a function of the hydrogen content in a TiMn1.5H
x
(x<0.31) electrode. The reaction order of hydrogen in the electrode is estimated as 0.67 and the activity coefficient of hydrogen is found to be unity. The influence of the absorbed hydrogen on the equilibrium potential is discussed. It is shown that TiMn1.5H
x
has low power drop during discharge and is a promising electrode material for use in hydrogen cells and other devices.
Nondestructive Measurement of Minority Carrier Lifetimes in Si Wafers Using Frequency Dependence of ac Photovoltages
Authors: Honma Noriaki , Munakata Chusuke , Itoh Haruo , Warabisako Terunori
Published: November 2005

Frequency dependence of ac photovoltages in p-n junctions has been measured while changing the chopping frequency of a photon beam with a wavelength of 1.15 µm. The chopping frequency was varied between 2 Hz and 200 kHz. When substrate thickness is larger than carrier diffusion length, minority carrier lifetime is obtained from the bending frequency which appears in photovoltage vs frequency curves on a logarithmic scale. The ratio of diffusion length to substrate thickness should be smaller than 0.27 to obtain lifetimes within 10% error due to infinite surface recombination velocity. When the substrate thickness is much smaller than carrier diffusion length, the bending frequency is determined by the substrate thickness. The longest lifetime is thus limited by the substrate thickness and the shortest by the photocurrents generated in surface and junction depletion layers.
LPE Growth of In1-xGaxAs1-yPy on GaAs0.7P0.3
Authors: Fujii Sadao , Sakai Shiro , Umeno Masayoshi
Published: November 2005

Various In1-x
Ga
x
As1-y
P
y
epitaxial crystals with mirror-like surfaces were grown on GaAs0.7P0.3 substrates by LPE employing the two-phase-solution technique. The arsenic atomic fraction in the melt (X
As
l) first increased with increasing X
Ga
l, but decreased above an X
Ga
l value of 0.03, while the solid As composition (1-y) increased monotonically. This somewhat strange behavior is explained as an increase in the As segregation coefficient with the increase in the As or Ga solid composition (x or 1-y), which results from the large value of the GaAs fusion temperature.
Construction and Performance of a Rigid Massive Copper Nuclear Demagnetization Stage
Authors: Okuda Yuichi , Ikushima Akira J.
Published: November 2005

A massive copper rod was machined to form a single-stage nuclear demagnetization stage consisting of a large number of 1.5 mm-thick-fins separated by slits 0.5 mm wide. An effective mass of 37 moles and a total mass of 60 moles of copper under a field of 6.5 T were demagnetized from an initial temperature of 14.5 mK, and a temperature of 0.2 mK was achieved at 0.02 T. The total heat leak was 1.5 nW 10 days after the initial 4He transfer, and was further reduced to 0.5 nW in 30 days. A time-dependent heat leakage was detected, but this was rather small. A possible eddy-current problem thought likely to affect the stage did not arise. The stage was found to be superior to conventional copper-bundle nuclear stages.
Dependence of Evolution of Field Reconnection at Coil End Region on Mirror Field in FRC Formation Stage
Authors: Ogi Sukeomi , Shiratani Masaharu , Takamatsu Masahiro , Watanabe Yukio , Akazaki Masanori
Published: November 2005

The effect of a mirror field on field reconnection in an FRC formation stage has been experimentally investigated. Reconnection is promoted when the mirror-field intensity is above a critical value at which the azimuthal electron drift velocity exceeds the ion sound velocity. This implies that the generation of some instabilities is important for the reconnection.
Simulation Experiment on Removal of Carbon Film from Observation Window of Carbonized Fusion Machine
Authors: Sakamoto Yuichi , Ishibe Yukio , Okazaki Kiyohiko , Oyama Hitoshi
Published: November 2005

Although metal and oxygen impurities in nuclear fusion machines can be reduced by first-wall carbonization, this procedure contaminates the surfaces of observation windows and other parts. This paper describes the removal of carbon films from a quartz sample using a locally produced ECR hydrogen plasma as a method of overcoming this problem.
Configurational and Structural Models for Photodarkening in Glassy Chalcogenides
Authors: Tanaka Keiji
Published: November 2005

Mechanisms of the reversible photodarkening phenomenon have been studied for amorphous S and Se. These materials exhibit smaller photodarkening effects when illuminated with sub-bandgap illumination at 80 K. A configurational model is proposed for interpreting the results, and parameters characterizing the model are estimated. This model is connected with a structural model which assumes photoinduced bond twisting. By using the modified valence-forcefield constants, it is shown that the structural model is quantitatively consistent with the configurational model. These models can explain most experimental results related to photodarkening, including the pressure and temperature dependence. The models can also be applied to photodarkening in glassy chalcogenide alloys.
Meltback of GaAs0.6P0.4 Substrate in LPE Growth of InGaAsP
Authors: Fujii Sadao , Furuta Shigeru , Sakai Shiro , Umeno Masayoshi
Published: November 2005

The meltback of a GaAs0.6P0.4 substrate was performed using an In melt containg Ga and As atoms. The experimental results and theoretical calculatios showed that the important factor in obtaining a good surface is to maintain the correct degree of unsaturation (-ΔT) of 5∼30°C defined by the difference between the saturation temperature and the meltback temperature. Although no difference was found in the overgrown InGaAsP layer, an apparent improvement in the interfacial quality was found by etching back the substrate just before the growth.
The Depth Profiling of the Crystal Quality in Laser-Annealed Polycrystalline Si Films by Raman Microprobe
Authors: Inoue Yasuo , Nakashima Shin-ichi , Mitsuishi Akiyoshi , Nishimura Tadashi , Akasaka Yoichi
Published: November 2005

The variation of crystal quality with depth in laser-annealed polycrystalline Si films has been examined for angle-lapped specimens using Raman spectroscopy. Changes in the Raman shape and intensity were analyzed by a convolution method assuming that the strain and structural disorder vary with depth. From this analysis we determined the distribution of the residual strains and structural disorders in the polycrystalline layers recrstallized solid-epitaxially.
Thermally-Stimulated Current Measurements and Localized States in Polychlorophenylacetylene
Authors: Onoda Mitsuyoshi , Amakawa Kiyoshi , Gu Hal Bon , Yoshino Katsumi
Published: November 2005

Thermally-stimulated currents (TSC) in conjugated conducting polymer (polychlorophenylacetylene, PCPA) and their doping effects were studied. The TSC spectra in undoped and I2 doped PCPA are very complicated. The TSC is enhanced upon increasing the I2 concentration and a main peak is observed at around 30∼60°C. This peak was separated by the thermal-cleaning method. The trap depths evaluated from an Arrhenius plot (log i vs 1 / T) of the initial rising part of the separated peak were about 0.24 and 0.4 eV, respectively, regardless of the amount of dopant. It is considered that a localized center either comprises existing defects originally in the PCPA or defects produced by doping with I2.
Thermodynamic Theory of III-V Semiconductor Ternary Solid Solutions
Authors: Onda Tomohiro , Ito Ryoichi , Ogasawara Nagaatsu
Published: November 2005

A new thermodynamic theory of III-V semiconductor ternary solid solutions is proposed, based on the bond picture of crystalline semiconductors. An expression for the free energy which includes the effect of short-range clustering is derived, and the degree of the clustering is described by introducing five kinds of tetrahedral cell. The theory is also applied to the case of random mixing, yielding a new interpretation of the interaction parameter.
Surface Pinning Phenomena in Superconducting Chevrel-Phase PbMo6S8
Authors: Matsushita Teruo , Kajiyana Kiyonori , Yamafuji Kaoru , Hamasaki Katsuyoshi , Komata Toranosuke
Published: November 2005

Surface pinning was investigated by using an ac measuring method for superconducting PbMo6S8tapes and wire prepared by electroplating and diffusion methods. A strong surface pinning was observed only for specimens with shorter heating-up times. The highest obtained value of the surface critical current density was 1.40×1010Am-2atB=5 T, which is comparable to the bulk critical current density of Nb3Sn. Such a strong pinning seems to be mainly caused by fine grains in the surface region.
Critical Test of Coupled-Bunch Instability Theory
Authors: Kobayakawa Hisashi , Yamazaki Yoshishige , Kamiya Yukihide , Kihara Motohiro
Published: November 2005

Longitudinal and transverse coupled-bunch instabilities were observed in the Photon Factory storage ring. They were all caused by the high shunt impedances of the RF accelerating cavities and their properties were studied in detail. The frequency dependences of threshold currents of these instabilities were measured, and well described in terms of the frequency dependent structures of the cavity impedances. Absolute values of the thresholds are discussed in a comparison with perturbation theory.
Molecular Motions and Related Mechanical Relaxations in Linear Polyethylene Treated with Fuming Nitric Acid
Authors: Anada Yuichi , Kakizaki Maeko , Hideshima Teruo
Published: November 2005

Molecular motions and related relaxations in solid linear polyethylene degraded by fuming nitric acid were investigated from -170 to 100°C by means of broad-line nuclear magnetic resonance absorption (BL-NMR) and dynamic mechanical measurements. A second-moment vs. temperature curve shows three motional processes around 80, 0 and -140°C, which were named α, β' and γ3 in the order of descending temperature. The molecular origins of these processes are discussed on the basis of a BL-NMR study of a sample swollen with C2Cl4. The α-process is attributed to the motion of the chains in the lamellar core which is not affected by the acid treatment while the β'- and γ3-processes are attributed to the motion of the cilia on lamellar surfaces produced by the acid treatment. Mechanical relaxations corresponding to the β'- and γ3-processes were also observed.