bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature Dependence of Ionization Coefficients for InP and 1.3 µm InGaAsP Avalanche Photodiodes
Authors: Takanashi Yoshifumi , Horikoshi Yoshiji
Published: November 2005

Investigations were made on the temperature dependence of excess noise characteristics for InP and 1.3 µm InGaAsP APDs for the case where electrons are injected into the high field region. The effective ratio of the ionization coefficientsKeff(β/α) was found to decrease with decreasing temperature for both APDs. Theoretical investigations on hot carriers are combined with McIntyre's theory for the excess noise characteristics to explain the experimental results. The dominant scattering process for hot electrons is the intervalley scattering; this leads to the fact that the temperature dependence of the mean free path is greater in the case of electrons than holes. The theoretical analysis provides the best fit to the experimental results. On the basis of the theoretical results, the compositonal dependence of the mean free path for hot electrons is discussed.
Analysis of Soft X-Ray Photoelectric Yield and Absorption Spectra by Potential Scanning Technique–LiF and NaF near the F K-Absorption Edge–
Authors: Muranaka Takeshi , Kiyono Setsuo , Watanabe Takeshi
Published: November 2005

Soft X-ray photoelectric yield and absorption spectra obtained using the potential scanning technique were constructed empirically for LiF and NaF near the fluorine K absorption edge. In the model calculations carried out for the case of a nickel X-ray target, the incident X-ray intensity distribution was approximated by the intensity of the nickel bremsstrahlung isochromat spectrum represented by four parameters. Fluorine K absorption spectra of LiF and NaF were used to estimate the efficiency of the photocathode and the transmission coefficient of the absorber. The constructed spectra were able to reproduce essential features of the corresponding observed spectra. The relations between the observed and constructed spectra are discussed.
Narrow Spacing Drift Chamber
Authors: Akino Yoshio , Daigo Motomasa , Kato Sadayuki , Kono Koji , Miyachi Takashi , Toshioka Kouichi , Watanabe Ken-ichi
Published: November 2005

Linearity and efficiency of a 3-mm spacing drift chamber was examined with an electron beam. A spatial coordinate is measurable with an accuracy of 0.2 mm.
Criterions for Basic Assumptions in Kick-Out Mechanism of Diffusion
Authors: Kitagawa Hajime , Hashimoto Kimio , Yoshida Masayuki
Published: November 2005

Basic equations of diffusion by kick-out mechanism are non-linear. To obtain the solutions of these equations analytically, it is necessary to assume that interstitial impurity or interstitial silicon atoms are in thermal equilibrium. To obtain criterions for these assumptions, the basic equations are linearized under the conditions that concentrations of substitutional impurity, interstitial impurity and interstitial silicon atoms approach their thermal equilibrium values.
It is found that the thermal equilibrium concentration as well as the diffusion coefficient is an important factor for the criterions.
Pressure Dependence of Dielectric Breakdown in Liquid Nitrogen
Authors: Shiraishi Masazumi , Fujii Haruhisa , Yoshino Katsumi , Inuishi Yoshio
Published: November 2005

Breakdown voltage characteristics in liquid nitrogen (liq.N2) have been studied in the pressure range between 1 and 15 atm. For constant gap length, the breakdown voltage increases with increasing pressure and saturates at around 10 atm. For shorter pulse width, the increase in breakdown voltage with pressure becomes less remarkable. In a non-uniform field of a plane-needle electrodes system, the breakdown voltage of the negative needle configuration increases remarkably with increasing pressure but that of the positive needle is almost insensitive to the pressure. These results can be interpreted in terms of the suppression of the formation and the development of a gaseous bubble in the breakdown of liq.N2under high pressure and at short pulse width. The positive streamer seems to play an important role in initiating total breakdown under high pressure and at short pulse width.
Wall Structures of Bubble and Stripe Domains in Sputtered Ho-Co Alloy Thin Films Examined by High Voltage Electron Microscopy
Authors: Suzuki Takao
Published: November 2005

Wall structures of stripe and small bubble domains in sputtered Ho
x
Co100-x
alloy films (14≤x≤29) examined by high voltage Lorentz electron microscopy are discussed. A peculiar image which varies locally in contrast and in width along the wall (direction) was found. This variation is thought to be due to the local fluctuation in density of Bloch lines. Two types of wall structures of small bubbles of a diameter less than a few thousand Å are discussed. The magnetization distribution for Type 1 is similar to a vortex, and that for Type 2 is different from that reported by Grundy et al.
New Far Infrared Laser Lines from Optically Pumped Methyl Alcohol and Their Assignments
Authors: Sokabe Noburu , Sasabe Tohru , Kimura Tomoshi , Yasuda Yukio , Murai Akira
Published: November 2005

Four new far infrared (FIR) laser lines have been observed from methyl alcohol optically pumped by R branch lines of the CO2 9 µm band. An oscillator-amplifier pump source was used with an open type FIR resonator. New assignments are given for ten FIR laser lines including the three new lines observed in the present work.
Non-Axisymmetric Alfvén Wave Excited by a Helical Coupler in an Inhomogeneous Plasma
Authors: Amagishi Yoshimitsu , Inutake Masaaki , Akitsu Tetsuya , Tsushima Akira
Published: November 2005

Non-axisymmetric Alfvén waves are excited with a helical coupler in a finite beta and a cylindrical inhomogeneous plasma surrounded by a conducting wall. The helical coupler, which consists of two symmetrical helical windings, exhibits a strong propagation directionality; slow waves of the m=-1 mode and fast waves of the m=+1 mode can be launched simultaneously from the coupler, but propagate in opposite directions along the static magnetic field. Dispersion relations including the attenuation length for both modes are compared with a magnetohydrodynamic theory given by Woods on the assumption of appropriate boundary conditions. As a nonlinear phenomenon, subharmonic slow Alfvén waves of the m=-1 mode have been observed when the pump frequency is close to or above the ion cyclotron frequency.
Sintering of Polycrystalline Diamond Cube for High Pressure Anvil
Authors: Mishima Osamu , Endo Shoichi
Published: November 2005

A sintering experiment was carried out to obtain a large polycrystalline diamond aggregate with a desired shape. Apparatus for generating high pressure and temperature in a large volume required for sintering is described. Cubic aggregate with an edge length of about 9 mm has been otained by sintering of diamond powder in the presence of a cobalt binder at about 65 kbar and 1650°C. The obtained diamond aggregate can be used in the near future as an anvil in order to produce extremely high pressure in a substantially large volume.
Film-Oscillating Method for X-Ray Diffraction with a Diamond Cell
Authors: Toyoda Shuhei , Kawamura Tetsuya , Mishima Osamu , Endo Shoichi
Published: November 2005

The oscillation of a film about the axis of the incident X-ray beam has been examined in order to improve the quality of the polycrystalline diffraction pattern obtained under pressure with a diamond cell. The diffraction lines become smooth, and the resulting error is negligible.
A Fast X-Ray Absorption Spectrometer for Use with Synchrotron Radiation
Authors: Matsushita Tadashi , Phizackerley R. Paul
Published: November 2005

A quasi-parallel and polychromatic beam of synchrotron radiation is focused and dispersed by a curved crystal, so that the energy of each ray of the focused beam varies as a function of convergence angle through the focus. The specimen is placed at the focus. By measuring the X-ray intensity distribution across the beam behind the focus, in the presence and absence of the specimen, the absorption spectra of Cu and Ni metal foils were obtained. Using an X-ray film as the detector, a spectrum from a Cu foil was obtained in 0.1 seconds when the SPEAR storage ring at Stanford was operated at 3.1 GeV and 80 mA. The energy resolution is approximately 2.0 eV and the energy range of the spectrum is approximately 1 keV.
Growth and Electrical Properties of Highly-Conductive As-Grown Zinc Selenide Crystals Grown from the Melt
Authors: Kikuma Isao , Furukoshi Mitsuo
Published: November 2005

Highly n-type zinc selende crystals up to 0.3 (Ωcm)-1 were grown from the melt with excess Zn under argon pressure. Resistivity and Hall effect measurements show that the resistivity of the as-grown crystals depends on the amount of excess Zn, which reduces the concentration of compensating acceptors.
Long Term Stability of Zn-Diffused Green Emitting TGS Grown GaP LED's
Authors: Schairer W. , Marshall A. J. , Gillessen K.
Published: November 2005

Green emitting LED's have been prepared by Zn-diffusion into GaP grown by the Temperature Gradient Solution (TGS) growth method. The long term stability of these diodes is comparable to the stability of diodes diffused into vapor phase epitaxial material. The degradation process has been investigated and the emission spectrum was found to be stable in time. Diodes exhibiting structures due to twinned regions or variations in the brightness of the emitting surface degrade with the same rate as completely uniform diodes. The structure of either kind does not change in time. Space resolved luminescence measurements show, that brightness variations are most likely due to randomly distributed non radiative centers.
Effect of Isothermal Annealing on Magnetic Properties of Sn1-xCrxTe Crystals
Authors: Inoue Masasi , Oshima Hisato , Yagi Hisao , Tatsukawa Toshiaki
Published: November 2005

Magnetization measurements were carried out in the temperature range 77–300 K on Sn1-x
Cr
x
Te crystals grown by the Bridgeman method (degenerate near-ferromagnetic semiconductors). Isothermal annealing in Zn vapor (at 600°C, followed by quenching in water) was found to be effective in reducing Sn vacancies and lattice strains; e.g., the Curie temperature and the coercive force for a sample with x=0.5 at.% varied from 160 K to 300 K and from 3 kOe to 600 Oe, respectively, with increasing annealing time (5 min-7 days). Heat treatment in vacuum also reduced the coercive force, but no appreciable change was observed in the Curie temperature. A qualitative discussion is presented here on these structure-sensitive properties.
An Easily-Constructed Rotating Tungsten Anode
Authors: Mitsuhashi Toshiyuki
Published: November 2005

A rotating tungsten anode of diameter 97 mm has been constructed by wrapping a thin tungsten plate around a water-cooled copper body with hoops. The anode was operated continuously at 40 kV and 60 mA at a target revolution of 1800 rpm, without sustaining any damage. The focus size was about 3 mm×0.6 mm.
Electrical Resistivity of C-15 Compounds Zr1-xTaxV2
Authors: Oota Akio , Kamatani Yasuhiro , Noguchi Seiichiro
Published: November 2005

The ZrV2 compound shows resistivity anomalies in the range between 70 and 120 K when it is annealed at 1050 and 920°C, while the anomalies do not appear when it is annealed at 800°C and as-cast. Comparison between X-ray diffraction patterns at 77 and 300 K suggests that these anomalies are caused by structural transformation. Resistivity measurements of Zr1-x
Ta
x
V2 compounds which are annealed at 1050°C show that similar anomalies to those for ZrV2 appear in Zr0.95Ta0.05V2, while no anomalies appear in Ta-rich compounds with x≥0.10. The low temperature results of Zr1-x
Ta
x
V2 conform well with the T
3 law of the Wilson theory. The high temperature results of these compounds, on the other hand, show a deviation from the linear T behavior predicted by this theory. The phenomenological expression based on the saturation model conforms well to the high temperature results.
X-Ray K-Absorption Spectra and Electronic Structures of Vanadium Hydrides and Deuterides
Authors: Tanaka Kazuhide , Sugiura Chikara , Nakai Shun-ichi , Ohno Youichi
Published: November 2005

The K-absorption spectrum of pure vanadium undergoes remarkable changes when hydrogen or deuterium is added to the metal: fine structures near the K-edge diminish and become indistinct with a progressive upward shift of the edge, and other structures well above the edge are lowered in energy. These changes suggest that an electronic structure with p-component above the Fermi level is strongly perturbed by the presence of interstitial hydrogen atoms. The data are discussed in the light of current band calculations on vanadium and its hydrides.
A Vacuum Féry Polarizing Monochromator
Authors: Onaka Ryumyo
Published: November 2005

A vacuum double monochromator with two crystalline quartz prisms was designed and constructed. The monochromator is capable of providing plane-polarized light down to 170 nm using a conventional D2 lamp. The prisms are of the Féry type, so they are able to focus themselves without auxiliary mirrors, improving the efficiency of the monochromator. The monochromator has already been used in the study of the electro-optic effects in KDP and ADP, and is now being used in the study of depolarizers in the near-vacuum region.
X-Ray Topographic Images of Oxidation-Induced Frank Sessile Dislocation Loops in Thin Silicon
Authors: Kawado Seiji
Published: November 2005

The difference in image visibility between the Lang method and the double crystal method has been studied in (001) silicon wafers about 13 µm thick containing oxidation-induced Frank sessile loops. Topographs taken with several reflections using different radiations have shown that the double crystal method can reveal the Frank loops even in crystals thinner than the lower thickness limit of 0.3 ξg ( ξg: extinction distance) in the Lang method. This arises from the difference in image contrast formation between the two methods. The double crystal method is a useful way of studying lattice defects in very thin crystals.
X-Ray Induced Currents in Polyvinylidene Fluoride
Authors: Mizutani Teruyoshi , Sugiura Nobuaki , Suzuoki Yasuo , Ieda Masayuki
Published: November 2005

The radiation-induced current J
RIC during X-ray irradiation and the delayed radiation induced current J
DRIC after cessation of irradiation were investigated in β-form polyvinylidene fluoride (PVDF). J
RIC showed complicated transients and both J
RIC and the dark current J
d decreased with field in the high-field region. The TSC spectra in β-PVDF thermoelectrets and the discharging currents revealed the accumulation of hetero-space charge, which is closely related to the decrease of J
d with the field. Thus the anomalous transients and field-dependences of J
RIC could be qualitatively explained through the space charge.
The temperature and X-ray-intensity dependences of J
RIC and the temperature dependence of the time constants for the decay of J
DRIC are also discussed on the basis of a simplified band model with a single set of electron traps.
Fine Particles of Titanium Prepared by Gas Evaporation
Authors: Kobayashi Makoto , Yatsuya Shigeki , Mihara Kazuhiro
Published: November 2005

The crystal structure and the crystal habit of Ti particles are studied by electron microscopy. The particles grown in the intermediate zone show the hcp structure of the low temperature phase, but the crystal habit is a truncated rhombic dodecahedron characteristic of the bcc structure of the high temperature phase. Since the lattice relation between the observed hcp structure and the corresponding bcc structure coincides with that of martensite transformation, it is concluded that the Ti particles are transformed martensitically to the hcp structure after nucleation with the bcc structure. An unknown structure at the corners of the hcp particles is also found.
Theoretical Considerations on Ion Channeling Effect through Silicide-Silicon Interface
Authors: Ishiwara Hiroshi , Saitoh Shuichi , Hikosaka Kohki
Published: November 2005

The ion channeling effect in hetero-epitaxial structures is considered theoretically. Four dechanneling factors at the film-substrate interface are discussed, i.e., (1) a transition layer, (2) lattice imperfection due to the mismatch of lattice parameters, (3) discontinuity of atomic rows, and (4) deformation of the potential distribution inside a channel. These conditions are then applied to practical silicide-on-silicon structures, the metal elements and composition ratios suitable for epitaxial growth on Si substrates being determined from the lattice matching conditions, and the behavior of channeled ions at the interface being predicted using the dechanneling factors (3) and (4). It is concluded that the dechanneling probability is lowest for NiSi2 and CoSi2 on Si structures, and that a pronounced flux peaking effect is expected to be caused by the host atoms in a CrSi2 on Si structure.
Effects of High-Temperature Annealing on the Electrical Characteristics of SOS-MOSFET's
Authors: Sasaki Nobuo
Published: November 2005

Using SOS initially annealed in N2 at different temperatures from 1050 to 1150°C for up to 300 min, both n- and p-channel Si-gate SOS-MOSFET's are fabricated. In this fabrication, the total time at high temperature is limited within 120 min at 1050°C; the temperatures of other steps are kept lower than 900°C. A decrease in the field-effect mobility is found as the annealing time increases for n-channel devices in the saturation region; no change is observed in the mobility in the triode region. For p-channel devices, the field-effect mobility does not decrease in either the saturation or triode regions.
Plasma-Grown Oxide on InP
Authors: Kanazawa Kunihiko , Matsunami Hiroyuki
Published: November 2005

A plasma oxidation of InP has been realized for the first time. The resistivity of the plasma-grown oxide is about 6×109 Ω cm, and the dielectric breakdown strength is in the range of 0.5–1×106 V cm-1. The electrical characteristics of the surface states at the plasma-grown oxide-type InP interface have been investigated using MOS capacitors, which yield a surface state distribution having a minimum density of 1–3×1011 cm-2 eV-1.
1.5 µm Region BH Laser Array
Authors: Suzuki Yoshio , Noguchi Yoshio , Takahei Kenichiro , Nagai Haruo , Iwane Genzo
Published: November 2005

The 1.5 µm wavelength region InP/InGaAsP laser arrays with four buried heterostructure (BH) lasers were fabricated with a high processing yield rate. The average threshold current and emission wavelength were about 50 mA and 1.47 µm under cw operation. The laser arrays were mounted with the junction-side up and four lasers could be operated independently as well as simultaneously.
Galvanomagnetic Study of 2-Dimensional Electron Gas in AlxGa1-xAs/GaAs Heterojunction FET
Authors: Narita Shin-ichiro , Takeyama Shojiro , Luo Wen Bin , Hiyamizu Satoshi , Nanbu Kazuo , Hashimoto Hisao
Published: November 2005

Measurements of the Hall and Shubnikov-de Haas effects of a 2-dimensional electron gas in an Al
x
Ga1-x
As/GaAs heterojunction interface have been performed. The electron density and mobility decayed together when the gate voltage was applied. The data of the Hall voltage and the source-drain current as functions of the gate voltage are transformed to magnetoconductances σ
x
x
and σ
x
y
, using Wick's theory to clarify the quantization of the conductance at the Landau level tails.
Magnetoconductance Investigations of AlxGa1-xAs/GaAs Heterojunction FET in Strong Magnetic Fields
Authors: Narita Shin-ichiro , Takeyama Shojiro , Luo Wen Bin , Hiyamizu Satoshi , Nanbu Kazuo , Hashimoto Hisao
Published: November 2005

In strong magnetic fields, the magnetoconductance of an electron gas formed in an Al
x
Ga1-x
As/GaAs heterojunction interface has been studied. It has been found that the localization effect of the electron gas in the interface at tails of Landau levels is not so remarkable at the range between the spin-split levels of the first Landau level compared with that between the first and second Landau levels, and an abnormally large effective g-value has been observed. Several differences between phenomena in Si-MOS FET and those in Al
x
Ga1-x
As/GaAs heterojunction FET are discussed.
Determination of the Density of State Distribution of a-Si:H by Isothermal Capacitance Transient Spectroscopy
Authors: Okushi Hideyo , Tokumaru Yozo , Yamasaki Satoshi , Oheda Hidetoshi , Tanaka Kazunobu
Published: November 2005

An ICTS (Isothermal Capacitance Transient Spectroscopy) theory for a system of continuously-distributed gap states is given and experimental data by the ICTS applied to P-doped a-Si:H Schottky barrier diode are presented. It is shown that the ICTS is a useful tool for the study of gap states of a-Si:H whose material parameters are strongly temperature-dependent.
Precipitation Behavior in a Cu-4.5 wt%Co Alloy
Authors: Matsumura Syo , Seno Yoshiki , Tomokiyo Yoshitsugu , Oki Kensuke , Eguchi Tetsuo
Published: November 2005

Precipitation behavior during aging at 873 K in a Cu-4.5 wt%Co alloy was investigated by means of electron microscopy. The sets of satellites along <100> directions flanking the matrix reflections were observed in the electron diffraction patterns of samples in the early stage of aging. With the progress of aging, the satellite reflections moved towards the matrix spots. The arrays of precipitates aligning along <100> directions were locally observed in images.
Abnormality at the Interface of p-Type InP Grown by LPE
Authors: Nakano Yoshinori , Takahei Kenichiro , Noguchi Yoshio , Nagai Haruo , Nawata Kiyoshi
Published: November 2005

Current-voltage characteristics of various types of InP homo-junctions grown by LPE were studied. Abnormal characteristics of p-type InP interface were found in comparison to n-type InP interface and they were found to be due to the presence of abnormal high resistivity region near the surface of p-type InP. The existence of this high resistivity region seems to be essentially related to the properties of p-type InP surface and LPE growth process.
Aging Effects of Li-Ti-O Superconducting Compounds
Authors: Inukai Takashi , Murakami Toshiaki , Inamura Takahiro
Published: November 2005

Aging effects in hot-pressed Li-Ti-O superconductors were studied by measuring electrical resistivity. When samples are stored in dry air, the resistivity is quite stable, but it is not stable in wet air. Lithium carbonate formation was detected in the sample by X-ray diffraction, showing a resistivity increase. It is thought that this lithium carbonate was formed by a reaction between Li-Ti-O and water on the sample surface. This consideration is supported by the fact that high density samples are more stable than those of low density.
Fabrication and Visible-Light-Emission Characteristics of Room-Temperature-Operated InGaPAs DH Diode Lasers Grown on GaAs Substrates
Authors: Mukai Seiji , Yajima Hiroyoshi , Shimada Jun'ichi
Published: November 2005

The fabrication of InGaPAs DH diode lasers, about 704 and 725 nm in wave length at 300 K, on GaAs substrates is described. Active layers of DH wafers tend to be rough with increasing the concentration of As in them. The threshold of pulse-current density for the diodes is typically 1.5×105 A/cm2. Differential quantum efficiency per one facet of these diodes varies from 1 to 3.4%. A power density as high as 2×106 W/cm2 is achieved at a mirror facet, on which no mirror damage is caused.
Forbidden Transition in Helium for Measurement of Fluctuating Electric Fields in Plasmas with Aid of Resonant Absorption
Authors: Oda Toshiatsu , Kawasaki Ken
Published: November 2005

Possible forbidden transition in helium is suggested for the measurement of fluctuations in plasmas. Instead of the three-level system, four-level system is proposed; one of the lower levels is a metastable state 21S, from which the resonant absorption is performed by using a high-power dye-laser to populate an upper level. A result calculated quantum mechanically is presented. The advantages of this method as compared with the usual technique of the plasma satellite line are discussed.
Colorimetric Measurement of the WO3 Electrochromic Display
Authors: Furuta Tomofumi , Shimomura Teruo , Mada Hitoshi , Kobayashi Shunsuke
Published: November 2005

Amorphous WO3/electrolytic solution-type electrochromic displays (ECDs) have been examined colorimetrically using the CIE 1976 (L
*
u
*
v
*) color space including their transient characteristics. These data are shown to be strongly dependent on the thickness of WO3 film; the optimum thickness is 0.4 µm. Obtained lightness L
* of ECDs in the OFF state is 90 and the color difference between the OFF and ON states is 85, which is incomparably superior to those of the existing liquid crystal displays.
Soft X-Ray Tomography of the m=2 Magnetic Island Structure in the JIPP T-II Tokamak
Authors: Nagayama Yoshio , Tsuji Shunji , Kawahata Kazuo , Noda Nobuaki , Tanahashi Shugo
Published: November 2005

Soft X-ray Tomography has been developed in order to obtain a 2-dimensional view of a tokamak plasma cross-section. The image reconstruction of them=2 magnetic island structure has been successfully demonstrated by the use of this technique. The higher Fourier components deform them=2 magnetic islands. It is confirmed that the poloidal magnetic fluctuations called Mirnov oscillations are caused by the rotation of the magnetic islands.
Impurity Absorption Losses in the Infrared Region due to 3d Transition Elements in Fluoride Glass
Authors: Ohishi Yasutake , Mitachi Seiko , Kanamori Terutoshi
Published: November 2005

Optical absorption spectra of 3d transition elements (Ti, V, Cr, Mn, Fe, Co, Ni and Cu) in zirconium tetrafluoride based glasses are measured. Absorption bands of Fe, Co, Ni and Cu, having their peaks in the near infrared region, extend their tails beyond a wavelength of 2 µm. Absorption losses due to these elements are less than several dB/km/ppm at a wavelength of 3 µm. The losses are less than one-tenth of those cansed by rare earth elements. Thus contamination with 3d transition elements exerts a less adverse influence upon the transmission loss in fluoride glass optical fibers than that due to rare earth elements.
Electrostatic Ballooning Mode in Toroidal Plasma
Authors: Itoh Kimitaka , Tuda Takashi , Tokuda Shinji , Itoh Sanae-Inoue
Published: November 2005

The electrostatic high-n ballooning mode equation is solved, preserving the radial structures of the electron and ion Z-functions. Two branches of ballooning instability are found. The Pearlstein-Berk mode remains stable in a torus with magnetic shear, while the ballooning mode is always unstable and is especially important for T
e/T
i∼O(1). The instabilities are characterized by large growth rates and small real frequencies ω*∼γ>|ω|∼0.
Very Steep Profile Resist Pattern Preparation by Reactive Ion Etching with Ar+CH4 Gas Mixture
Authors: Watanabe Iwao , Yoshihara Hideo , Saitoh Yasunao , Matsuo Seitaro
Published: November 2005

The resist sputter-etching characteristics and the deposition film morphology on a fine pattern were investigated. The resist pattern profile can be controlled by the Ar ion energy with a reduction in the resist pattern width. The hydro-carbon film deposition rate on the top edge of the fine pattern is higher than that on the sidewall. For fine pattern reformation, we attempted to combine the Ar sputter-etching effect with the hydro-carbon film deposition effect using CH4 gas. The resist pattern is reformed with an Ar+CH4 gas mixture plasma with no reduction in the resist pattern width.
High-Resolution High-Sensitivity Mass Spectrometer for Heavy Molecule Analysis
Authors: Matsuda Hisashi
Published: November 2005

An improved mass spectrometer for the analysis of very heavy molecules is proposed. It consists of a 60° sector magnetic field, a 90° toroidal electric field and a pair of electric quadrupole lenses. Stigmatic double focusing is achieved and second order image aberrations are corrected. A resolving power of 5000 at M=5000 is expected with a fairly small mass spectrometer (r
m=25 cm) with sufficient sensitivity (source slit width 0.15 mm). The narrow magnet gap (4.5 mm) is advantageous for analysing heavy molecules.
Selective Dry Etching of AlGaAs-GaAs Heterojunction
Authors: Hikosaka Kohki , Mimura Takashi , Joshin Kazukiyo
Published: November 2005

Selective dry etching of GaAs to Al
x
Ga1-x
As (x=0.3) using an etching gas composed of CCl2F2 and helium was studied. Etching was carried out at gas composition ratios of P
CCl2F2
/P
He above 0.25, total pressures of 0.5 to 5.0 Pa, and power densities of 0.18 to 0.53 W/cm2. A high selectivity ratio exceeding 200 and a clean etch profile were obtained at a gas composition ratio of P
CCl2F2
/P
He=1 operated at 5 Pa and 0.18 W/cm2. The etched profile of GaAs under the above conditions exhibited a nearly vertical-wall character.
Laser Power Multiplication in a Parametric Frequency Converter with a Cavity Dumper
Authors: Tanimoto Mitsumori , Yaoita Akira , Matsumoto Yuji , Koyama Kazuyoshi
Published: November 2005

It is shown theoretically that by using a parametric frequency converter with a cavity dumper, power enhanced laser pulses of moderately compressed pulse-duration, shorter wavelength and broader bandwidth can be obtained efficiently from relatively long fundamentals, resulting in useful laser-fusion driver pulses.
Screening of Hot Electron Energy Relaxation in a Semiconductor by Shallow Impurities
Authors: Otsuka Eizo , Ohyama Tyuzi , Fujii Kenichi
Published: November 2005

The energy relaxation process of the photoexcited hot electron system in InSb is investigated at 4.2 K by the time-resolved cyclotron resonance method at the far-infrared laser wavelength of 84 µm. It is found that the electron temperature, at first more than 40 K, cools down at a much slower rate than predictable by electron-phonon interaction. The screening by shallow donor impurities is stressed.
S-Doping of MBE-GaSb with H2S Gas
Authors: Gotoh Hideki , Sasamoto Kiyoshi , Kuroda Shigeru , Yamamoto Tohru , Tamamura Kohshi , Fukushima Masayuki , Kimata Morihiko
Published: November 2005

The possibility of S-doping MBE-GaSb using H2S gas has been demonstrated. The sulfer atoms are thermally dissociated from the H2S gas, and are adsorbed at Sb vacancy sites. The S sticking coefficient depends on the Sb coverage. The electron mobility of S-doped GaSb is relatively low. This may be caused by a high compensation ratio and lattice mismatch between the GaAs substrate and the GaSb film. From the experimental results, the activation energy of the S-donor is estimated to be about 75 meV.
Low Threshold PbSnSeTe-PbSeTe Lattice-Matched Double-Heterostructure Lasers
Authors: Horikoshi Yoshiji , Kawashima Minoru , Saito Hisao
Published: November 2005

Very low threshold current density lasers with an 11 µm emission wavelength at 4.2 K have been fabricated from the lattice-matched Pb0.85Sn0.15Se0.02Te0.98-PbSe0.08Te0.92 DH wafers grown by liquid phase epitaxy on a Pb0.8Sn0.2Te substrate. The active layer thickness, which minimizes the threshold current density, has been determined to be about 1 µm from the calculated optical confinement factors assuming a linear gain-current relationship. Lasers with a 1 µm active layer thickness and a 500 µm cavity length exhibited threshold current densities as low as 65 A/cm2 at 4.2 K and 350 A/cm2 at 77 K. The measured internal optical loss was as low as 2.8 cm-1 at 4.2 K.
Multiple SOI Structure Fabricate by High Dose Oxygen Implantation and Epitaxial Growth
Authors: Irita Yukio , Kunii Yasuo , Takahashi Mitsutoshi , Kajiyama Kenji
Published: November 2005

A triple SOI (Silicon crystal On Insulator) structure has been fabricated on (100) and (111) Si substrates, utilizing three SIMOX (Separation by IMplanted OXygen) cycles. The SIMOX process consists of high-dose oxygen implantation followed by annealing and epitaxial growth of silicon, and provides good surface morphology. The top Si layer of the present triple SOI is single crystalline, which is confirmed by reflection electron diffraction and Rutherford backscattering measurement.
Elastic Softening at the Order-Disorder Phase Transition in a Plastic Crystal RbNO2
Authors: Hirotsu Shunsuke , Miyamoto Masaaki , Yamamoto Ikuo
Published: November 2005

All of the elastic constants of cubic RbNO2 have been measured as functions of temperature. A marked softening of the angle shear stiffness c
44 as the structural phase transition point is approached has been found. A symmetry consideration reveals that a bilinear coupling is allowed between the shear strain and the reorientational motion of nitrite ions. The transition can be regarded as an elastic phase transition in which the ordering of nitride ions induces elastic instability.
Relaxation of Ion Energy Spectrum Just after Turbulent Heating Pulse in TRIAM-1 Tokamak
Authors: Nakamura Kazuo , Hiraki Naoji , Nakamura Yukio , Itoh Satoshi
Published: November 2005

The temporal evolution and spatial profile of the ion energy spectrum just after the application of a toroidal current pulse for turbulent heating are investigated experimentally in the TRIAM-1 tokamak and also numerically using the Fokker-Planck equation. The two-component ion energy spectrum formed by turbulent heating relaxes to a single one within τi (the ion collision time).
A New Type of Very-High Temperature Heating Stage and In Situ Experiments on α-Al2O3 Crystals
Authors: Komatsu Masao , Fujita Hiroshi , Matsui Hideki
Published: November 2005

A new type of very-high temperature stage for a 3 MV electron microscope has been developed, with which the specimens can be tilted up to ±8° around any axis in a wide temperature range up to 2300 K. In-situ heating experiments on Al2O3 powder have been carried out with this stage, and the detailed processes of sintering, void disappearance and boundary migration were observed.
Residual Voltage in Polyethylene
Authors: Yoshino Katsumi , Kyokane Jun , Yun Munsoo , Nojima Ken-ichi , Inuishi Yoshio , Kashiwagi Nobuharu
Published: November 2005

A considerably high residual voltage can be observed even in non-degraded polyethylene by a non-contacting method using an electrostatic voltmeter. This residual voltage increases nonlinearly with increasing applied voltage and duration of voltage application, but decreases as the duration of short-circuiting is increased.
A simple computer analysis is found to give good agreement with the experimental results using a carrier mobility of the order of 10-12 cm2/V·sec.
Development of a Laboratory EXAFS Facility and Its Application to Amorphous GeSe Semiconductors
Authors: Maeda Hironobu , Terauchi Hikaru , Tanabe Kazuhiro , Kamijo Nagao , Hida Moritaka , Kawamura Hajimu
Published: November 2005

A new type of X-ray spectrometer and detector system for performing extended X-ray absorption fine structure measurements in the laboratory has been developed. The spectrometer is equipped with an asymmetrically-cut flat crystal monochromator in the magnifying mode and converts the energy dispersion to position dispersion using a position-sensitive detector. Two advantages of this apparatus are that it has no moving parts and that it makes the X-ray path shorter. The application of the spectrometer to amorphous GeSe semiconductors is also presented to show its usefulness.
Precise Profiles for Arsenic Implanted in Si and SiO2 over a Wide Implantation Energy Range (10 keV–2.56 MeV)
Authors: Nakata Jyoji , Kajiyama Kenji
Published: November 2005

Arsenic ions were implanted into Si and SiO2 over a wide energy range (10 keV–2.56 MeV). Implantation profiles were precisely measured by the normal and glancing angle Rutherford backscattering method. They are closely approximated by joined half-Gaussian distributions.
For Si, the experimental R
p and Δ
R
p values are systematically ∼15% and ∼30% larger than the LSS calculation values over the present full implantation energy range of 10 keV–2.56 MeV. For SiO2 the experimental R
p and Δ
R
p values are systematically 20–30% and 40–50% larger over the same implantation energy range. The experimental third-moment, µp, is positive below ∼500 keV, and is negative above ∼500 keV implantation energy, for both Si and SiO2.
Numerical Analysis of Current versus Voltage Characteristics by Triangular Voltage Sweep in SiO2 Film
Authors: Yamashita Ken , Hino Taro
Published: November 2005

Current versus voltage characteristics by the triangular voltage sweep method are measured on mobile Na+ ions in the SiO2 film and the results are analyzed numerically. The voltage at which current becomes maximum shifts as the voltage sweep rate changes. This phenomenon cannot be explainaed by conventional quasi-equilibrium analysis, but is clearly expressed by the present numerical analysis. Asymmetry of current peaks for the positive and the negative sweep are interpreted by introducing ionic traps. The trap depths are estimated by an analysis of temperature dependence and discussed by a comparison with results of the thermally stimulated current.
A New Threshold Display Technique for Josephson Interferometer Logic Gates and Its Application to Gate Parameter Estimation
Authors: Yamauchi Yoshiki , Ishida Akira
Published: November 2005

A new sweep technique is described for displaying the switching threshold curves of Josephson interferometer gates. The technique is based on a CRT sweep in the form of a combined line and circular scan. It successfully displays the switching boundary even in the vortex-mode overlapping region. This new technique is also found to be quite effective for studying the relation between the gate threshold and the gate parameters in detail.
Ultrasonic Resonance Spectrometry with Fourier Synthesized Pseudorandom Noise Excitation and Its Application to a Lyotropiec Liquid Crystal
Authors: Nakamura Haruki , Naito Yasushi , Tsuboi Yukitoshi , Mitaku Shigeki , Okano Koji
Published: November 2005

Time domain measurement to obtain ultrasonic resonance spectra was made using Fourier Synthesized Pseudorandom Noise (FSPN) excitation in order to observe the viscoelastic property of a lyotropic liquid crystal. The FSPN with multiple frequency components was amplitude-modulated by a carrier signal with a much higher single frequency component, and a quadrature detection technique was used to obtain a shear ultrasonic resonance spectrum produced between two transducers. A reflection method was applied to observe mechanical impedance of viscous and elastic materials at about 3 MHz.
The viscosities obtained for standard viscous materials agreed well with literature values, and the rigidity and viscosity of a lyotropic liquid crystal of Sodium Lauryl Sulfate with water were measured; they were ∼106 dyn/cm2 and ∼0.1 P, respectively.
Experimental Study on Suppression of Detonation Waves
Authors: Terao Kunio , Kobayashi Hisanobu
Published: November 2005

In this experiment, detonation waves propagating in a stoichiometric propane-oxygen mixture through a channel containing an obstruction were investigated in order to clarify the cellular structure of the waves and also to find some methods for suppressing the detonation. The results suggest that triple shocks are formed by isochoric combustion accompanying spontaneous ignition behind the shock waves at the detonation front and that the propagation velocity must be decelerated to suppress the detonation, to the extent of keeping the temperature or the mixture so low that no spontaneous ignition takes place.
Determination of Reaction Constant of Exciton-Exciton Collision by Absorption Measurement
Authors: Ugumori Tadaki , Aoyagi Yoshinobu , Segawa Yusaburo , Namba Susumu
Published: November 2005

A new method is proposed for determining the reaction constant C of an inelastic exciton-exciton collision. By analysing the time behavior or exciton absorption, the value of C is obtained. This method is suitable for materials of low luminescence efficiency. The reaction constant of C≃10-8 cm3 s-1 is deduced from the time characteristics of exciton absorption in GaSe at 2 K.
Tunable Filtering Characteristics of Multilayered Optical Couplers Using Surface Acoustic Waves
Authors: Goto Nobuo , Miyazaki Yasumitsu , Akao Yasuo
Published: November 2005

The tunable filtering characteristics of multilayered optical couplers are investigated. The couplers consist of ZnS/Ta2O5/Nb2O5 films on Y-cut LiNbO3 substrates. The filtering bandwidth is 3–50 Å with a tuning sensitivity of 10-3–10-2 (MHz)-1. The acoustic power required for switching is some tens of mW.
Experimental results on the acousto-optic collinear interaction in optical couplers are first reported. The fundamental result of the acoustic frequency sensitivity agrees fairly well with the theory.
Isothermal Capacitance Transient Spectroscopy in MIS Structures
Authors: Yamaguchi Eiichi
Published: November 2005

A general formula for the capacitance transient response in an MIS structure has been developed, including the continuous density distribution of interface states and discrete multi-impurity levels. A new method of spectroscopic measurement is proposed for determining the density distributions and capture cross-sections of interface states and bulk impurity levels under isothermal conditions. The method is then applied to an n-InAs/anodic oxide MIS diode.
Measurement of Electron Cyclotron Emission from JIPP T-II Plasma
Authors: Kawahata Kazuo , Sato Masayasu , Tetsuka Tsutomu , Noda Nobuaki , Sakai Kiyomi
Published: November 2005

A rapid-scanning Fourier transform spectrometer has been developed to measure the electron cyclotron emission from JIPP T-II plasma. The electron temperature profiles and their time evolution have been obtained from measurements of the second harmonic electron cyclotron radiation emitted perpendicular to the magnetic field. Based on the absolute calibration of the spectrometer, absolute values of the electron temperature are obtained independently of Thomson scattering, and the values are within 30% of those with Thomson scattering.
Improvement in Open-Circuit Memory, Current Efficiency and Response Speed of an Amorphous WO3 Solid-State Electrochromic Device
Authors: Sato Yoshiyuki , Fujiwara Ryoji , Shimizu Isamu , Inoue Eiichi
Published: November 2005

The desirable configuration of an amorphous WO3 (a-WO3) solid-state electrochromic device (ECD) was examined in order to improve the poor open-circuit memory and low current efficiency observed in an a-WO3/Cr2O3 ECD. It was found that a device with an SiO2 (or Nb2O5) layer introduced between the a-WO3 layer and the Cr2O3 layer exhibited long open-circuit memory and good current efficiency. The charge dissipation in the a-WO3/SiO2 (or Nb2O5)/Cr2O3 ECD was as low as that in an a-WO3/liquid electrolyte ECD. In addition, reactive evaporation of Cr2O3 in an atmosphere of H2O activated by thermal electrons was attempted in an effort to better the response speed of the device.
Diamond Anvil Pressure Cell and Pressure Sensor for High-Temperature Use
Authors: Arashi Haruo , Ishigame Mareo
Published: November 2005

A new modification of the diamond anvil pressure cell was made for high-temperature and high-pressure use. After this modification, a high temperature of up to 700°C could be obtained at a pressure of up to 7 GPa. Various sensor materials for pressure measurement at high temperatures were also investigated. It was found that YAG: Eu3+ is a suitable crystal as a pressure sensor at high temperatures.
A Multi-Beam Interferometer and Its Use as a Screening System in Gynecologic Cytology
Authors: Fujii Ken-ichi , Suzuki Norihito
Published: November 2005

Clumps of cells remaining after the cell separation process present the greatest obstacle to the development of an automated screening system using flow cytofluorometry. There are two main problems caused by such clumps of cells. One occurs in the flow system, when the clumps block the nozzles, while the other occurs in the measuring system, when the clumps give a false fluorescence intensity. The former problem can be solved by designing the flow system appropriately, and the latter can be obviated by using a multi-beam interferometer.
A NbTi Superconducting Dipole Magnet Installed in a Pressurized Helium II Cooling Bath
Authors: Hosoyama Kenji , Kishiro Jun-ichi , Kohriki Takashi , Kudo Noboru , Kubo Tomio , Mitsunobu Shinji , Sakai Izumi , Suzuki Yoshihiro , Tsuchiya Kiyosumi , Yamamoto Akira , Hirabayashi Hiromi
Published: November 2005

A double-bath pressurized helium II cryostat for an accelerator NbTi test dipole was constructed. Heat leakage into the cryostat was 5 W at 1.8 K. The dipole was excited in the cryostat. After several quenchings in pressurized helium II, the dipole achieved a highest central field of 6.75 T with an excitation current of 6.6 kA.
Fabrication and I-V Characteristics of High-Tc Nb3Ge Microbridges
Authors: Hikita Makoto , Nakamura Kiko , Kubo Shugo , Igarashi Masaru , Kakuchi Masami , Kogure Osamu
Published: November 2005

High-T
c Nb3Ge microbridges are fabricated by electron-beam lithography combined with CF4 reactive sputter etching. The bridges are 0.48 µm wide and 0.36–0.6 µm long. The temperature dependence of I
c is found to be proportional to (1-t)5/2 at t>0.8 (t=T/T
c). This result means that the bridge region behaves like an inhomogeneous type-II superconductor film. 9.75 GHz microwave induced steps are observed throughout a wide temperature range. The steps are observed above 20 K in some bridges.
Alignment of a Liquid Crystal on an Anisotropic Substrate
Authors: Okano Koji , Matsuura Naoki , Kobayashi Shunsuke
Published: November 2005

A homogeneous (planar) alignment of nematic liquid crystal on an optically uniaxial substrate, the optic axis of which is parallel to the surface plane, is considered.
Based on the macroscopic theory of van der Waals forces, the contributions of the electrostatic dipolar forces and the dispersion force of the interfacial free energy between the liquid crystal and substrate are considered as functions of the angle between the optic axis of the substrate and the director of the liquid crystal.
A Thermionic Electron Emission Model for Charge Retention in SAMOS Structure
Authors: Nozawa Hiroshi , Kohyama Susumu
Published: November 2005

Charge retention in SAMOS structures at elevated temperatures is effectively described by a thermionic electron emission model from a floating polysilicon gate into the surrounding oxide. Experimental results showed sufficiently good agreement with the theoretical model. The barrier height and collision frequency derived from the experiments are reasonable (1.24 eV and 2.5×104/sec, respectively). Long term data retention in floating gate EPROM's can also be predicted by this model.
FEM Study of Low-Temperature Adsorption of Mixture of N2 and O2 on Tungsten
Authors: Sato Mieko
Published: November 2005

The adsorption of mixture of nitrogen and oxygen on tungsten surface at 80 K has been studied by the FEM method. The preferential adsorption of nitrogen is found to continue until a certain coverage is obtained. After the coverage the replacement of the adsorbed nitrogen by oxygen is found to occur and at last the oxygen-saturated surface is obtained. The coverage seems to be related to the saturation coverage of the atomical adsorption of nitrogen on tungsten at 80 K.
Extracted-Beam Divergence Calculations for a Liquid-Metal Ion Source
Authors: Ishitani Tohru , Koike Hidemi , Sakudo Noriyuki
Published: November 2005

The space-charge spreading of the beam in the ion-extraction region of a liquid-metal ion source is evaluated by calculating the ion trajectories. The rate of increase is the emission angle for the modified “Taylor cone” anode is expressed by a universal curve given by a function of (dI/dΩ)0
M
1/2/(V
AC/α)3/2. Here, (dI/dΩ)0 is the angular ion intensity on the anode surface, M is the atomic mass of a singly-charged ion, V
AC is the difference in potential between the anode and the cathode, and α is a shape factor for the anode.
Single Crystal Growth of Ba(Pb, Bi)O3 from Molten KCl Solvent
Authors: Katsui Akinori , Suzuki Minoru
Published: November 2005

A flux method using KCl as a solvent is proposed for the growth of Ba(Pb, Bi)O3 single crystals. The single crystals are obtained from a mixture of polycrystalline BaPb0.9Bi0.1O3 and KCl. The Meissner effect results and four-probe electrical resistance measurements indicate that the as-grown crystals are superconducting with a critical onset temperature of 10.2 to 10.8 K.