bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical and Optical Properties of Electrochemically Prepared Polyfuran
Authors: Ohsawa Toshiyuki , Kaneto Keiichi , Yoshino Katsumi
Published: November 2005

Polyfuran films are prepared electrochemically and found to exhibit electrical and optical properties similar to those of polythiophene and polypyrrole, though the electrical conductivity in a doped state is little lower than the latter two polymers. The resistivity of polyfuran is found to be very sensitive to humidity and its application as a sensor of humidity is proposed.
Growth of Microcrystalline SixGe1-x Alloy Films by Sputter-Assisted-Plasma CVD
Authors: Kohno Kenji , Nakashita Toshio , Iwaoka Teiji , Imura Takeshi , Osaka Yukio
Published: November 2005

Microcrystalline Si
x
Ge1-x
alloys are prepared at low substrate temperatures by the sputter-assisted-plasma CVD technique. The composition is widely controlled by changing the substrate temperature between 40 and 420°C. Microcrystalline nature is confirmed by Raman scattering spectroscopy showing the definite peaks of Si-Si, Si-Ge, and Ge-Ge lines, and by X-ray diffraction patterns. The grain size of the microcrystal is estimated to be 150–200 A.
Metastable-Atom Auger Deexcitation Spectroscopy of Clean and Oxygen-Covered Si(111) Surfaces
Authors: Nishigaki Satoshi , Takao Keiji , Yamada Tomohiro
Published: November 2005

The energy distribution of electrons emitted from clean and oxygen-covered Si(111) surfaces upon impact of metastable He*atoms was measured. The metastable deexcitation at the clean Si(111) surface was shown to occur predominantly via Auger deexcitation mechanism: He*+S→He+S++e- (S: surface). The adsorption process was monitored by this technique with a high sensitivity to the outermost atomic layer. Differences between the present metastable-atom deexcitation spectra and previous photoemission spectra are discussed.
Isoelectronic Double Doping Effect on Dislocation Density of InP Single Crystal
Authors: Tohno Shun-ichi , Kubota Eishi , Shinoyama Seiji , Katsui Akinori , Uemura Chikao
Published: November 2005

A Ga+Sb doping technique is proposed for reducing the dislocation density in LEC-InP crystals. Using SSMS and SIMS measurements, effective distribution coefficients of Ga and Sb in InP are estimated to be 3.35 and 0.12, respectively. Effectiveness of uniform Ga+Sb concentration doping all along the growth direction is presented. Nearly dislocation-free InP crystals 25 mm in diameter are prepared using Ga+Sb doping concentration above 6×1018 cm-3.
Analysis of Deposition Rate Distribution in the Photo-CVD of a-Si by a Unified Reactor with a Lamp
Authors: Kamisako Kōichi , Aota Katsumi , Tarui Yasuo
Published: November 2005

The deposition rate distribution in the photochemical vapor deposition (photo-CVD) of hydrogenated a-Si films from monosilane or disilane by a unified reactor with a lamp has been investigated. When the distance between a gas outlet and a substrate is kept short, a characteristic distribution of deposition rate occurs because of the influence of a reactant gas flow. Such distribution can be explained by analyzing a rate equation which is represented by terms of generation, diffusion and extinction of activated species. If we assume the activated species are SiH2 or SiH3 radicals, the lifetime of activated species can be estimated as 0.02 s.
Alternating-Current Ohmic Heating in a Helical Stellarator
Authors: Funato Yasuyuki , Kitajima Sumio , Watanabe Hiroshige
Published: November 2005

A toroidal plasma is generated successively by an alternating-current discharge in a helical or non-planar torus, and is confined quasi-stationarily by a longitudinal magnetic field with a high rotational transform angle. The particle confinement time obtained experimentally is estimated to be 3–10 ms, which is compared with theoretical values for this system, and is much larger than the time of pulse interval of the plasma production
Photoluminescence of InP Doping Superlattice Grown by Vapor Phase Epitaxy
Authors: Yamauchi Yoshiharu , Uwai Kunihiko , Mikami Osamu
Published: November 2005

An InP doping superlattice structure has been fabricated by hydride vapor phase epitaxy with a multibarrel reactor, using Zn and S as dopants. Layer thickness and doping level were varied from 150 to 2000 Å and 0.5×1018 to 8×1018 cm-3, respectively. Although Zn dopant diffusion into the n-layers occurred in the fabricated samples, photoluminescent peak wavelength shifts due to the indirect carrier transition in real space were observed at 77 K.
Epitaxial Relations in Lattice-Matched (Ca, Sr)F2 Films Grown on GaAs{111} and Ge(111) Substrates
Authors: Ishiwara Hiroshi , Tsutsui Kazuo , Asano Tanemasa , Furukawa Seijiro
Published: November 2005

Epitaxial relations in lattice matched Ca0.42Sr0.58F2 films grown on GaAs(111), (1̄1̄1̄) and Ge(111) substrates were investigated by 2-MeV 4He+ ion channeling and backscattering measurements. It was found that the epitaxial films on GaAs have an orientation indentical to that of substrates (type A), whereas those on Ge mainly exhibit an orientation rotated by 180° about the surface normal <111> axis (type B), though both substrates have nearly the same lattice constant.
Direct Observation of AlxGa1-xAs/GaAs Superlattices by REM
Authors: Yamamoto Naoki , Muto Shunichi
Published: November 2005

Cleavage surface of Al
x
Ga1-x
As/GaAs superlattices were observed by reflection electron microscopy using a conventional transmission electron microscopy, and cross sections of the superlattices were clearly shown as stripe patterns. Strain fields around the superlattice were revealed in a REM image. The irregularities in superlattice layers caused by roughness of a substrate surface were found to be relaxed in successive layers.
Cold Jet Infrared Absorption Spectroscopy: The ν3 Band of UF6
Authors: Takami Michio , Oyama Toshiyuki , Watanabe Tsunao , Namba Susumu , Nakane Ryohei
Published: November 2005

The ν3 band of UF6 is studied at a low rotational and vibrational temperature using a tunable diode laser. Infrared absorption in a pulsed supersonic free jet of UF6 is observed by phase sensitive detection synchronized with the pulse frequency. Absorption lines from P(21) to R(27) are measured for 238UF6 with a Doppler limit resolution. Only Q-branch peaks are observed for 235UF6 using naturally abundant isotopic species. Isotope shift for the ν3 band is determined to be 0.6040 cm-1.
All Niobium Nitride Josephson Junction with Hydrogenated Amorphous Silicon Barrier and its Application to the Logic Circuit
Authors: Aoyagi Masahiro , Shoji Akira , Kosaka Shin , Shinoki Fujitoshi , Nakagawa Hiroshi , Takada Susumu , Hayakawa Hisao
Published: November 2005

Josephson tunnel junctions with all niobium nitride (NbN) electrodes were fabricated with sputtered amorphous silicon (a-Si:H) films as tunnel barriers whose surfaces are oxidized by an rf-plasma oxidation. The specific capacitance of the fabricated junction strongly decreased with increase in the thickness of the a-Si:H film. The specific capacitance of less than 4 µF/cm2 was obtained for the a-Si:H thickness of about 2 nm. A logic circuit composed of four-junction logic (4JL) gates was fabricated using these junctions and was operated with the minimum logic delay of 9 ps/gate.
Characteristics of the Self-Quenching Streamer Mode in a Gas Counter
Authors: Kametani Hitoshi , Ijiri Hidenobu , Ohgaki Hideaki , Takahashi Yuho , Higuma Seiji , Imabeppu Satoru , Urase Kenji , Fujita Yasuyuki , Maesako Hironori , Sakae Takeji , Koori Norihiko , Matoba Masaru
Published: November 2005

The characteristics of the electron avalanche of the self-quenching streamer mode in a cylindrical counter filled with an argon-methane-ethanol mixture were measured as functions of the concentration of ethanol (another quenching gas), the diameter of the anode wire and the incident X-ray energy. New systematics in generation of the streamer were obtained.
Electron Affinities of Polystyrene and Poly(2-vinylpyridine) by Low-Energy Electron Inelastic Scattering
Authors: Ueno Nobuo , Sugita Kazuyuki , Seki Kazuhiko , Inokuchi Hiroo
Published: November 2005

Low-energy electron energy loss spectra including secondary electron bands and low-energy electron transmission spectra were measured for polystyrene and poly(2-vinylpyridine) thin films deposited on metal substrates. Almost all the features of these spectra could be explained as the result of electronic excitations localized in pendant molecules. The electron affinities of polystyrene and poly(2-vinylpyridine) were estimated as 0.4±0.1 eV and 0.3±0.1 eV, respectively, based on the one-to-one correspondence of the spectral features of these two types of spectra.
Influence of Chemical Structure on Electrical Conductionin Insulating Polymers
Authors: Mizutani Teruyoshi , Ikeda Seita , Ieda Masayuki
Published: November 2005

The electrical conductivities of polyethylene, polypropylene and related fluorinated polymers such as polytetrafluoroethylene and fluorinated ethylene propylene copolymer were measured using a corona electrode. The polarity of the dominant carriers making the greatest contribution to the current changed from negative to positive as the ratio of fluorine atoms to hydrogen atoms was increased. Electronegative fluorine atoms were concluded to provide deep trap sites for negative carriers and to suppress the current due to negative carriers. The results of surface potential decays and TSC's of corona-charged specimens also supported the above conclusion.
Metalorganic Molecular-Beam Epitaxial Growth and Characterization of GaAs Using Trimethyl- and Triethyl-Gallium Sources
Authors: Tokumitsu Eisuke , Kudou Yoshimitsu , Konagai Makoto , Takahashi Kiyoshi
Published: November 2005

The metalorganic molecular-bean epitaxial (MOMBE) growth of GaAs using trimethylgallium and triethylgallium has been studied. The results of introducing hydrogen into the system are also descrived. Introducing ionized hydrogen into the TMG-As4 system reduced the carrier concentration from 1×1020 cm-3 to 1×1018 cm-3. Using TEG as a Ga source, epitaxial layers grown at temperatures below 580°C showed n-type conduction and a carrier concentration of about 1×1017 cm-3, while those grown at higher temperatures showed p-type conduction.
Electron Trapping Induced by High-Energy Ionizing Radiation in SiO2
Authors: Shimaya Masakazu , Shiono Noboru
Published: November 2005

Electron trapping by positively-charged centers and neutral centers induced in SiO2 by 1 MeV electron and gamma-ray (Co60) irradiation was studied by the avalanche injection technique. Two kinds of positively charged trap with cross sections of 2×10-13 and 3× 10-14 cm2 were identified. The effective density of these traps increased linearly with the total absorbed dose and with the 0.45 power of the total dose, respectively, suggesting that there is another origin of positively-charged traps besides trapped hole centers. Two neutral traps with cross sections of 6×10-16 and 6×10-17 cm2 were also identified, and the effective density of these traps was found to increase linearly with the total dose. Under a positive gate bias, this effective density was about twice that under a negative bias. Neutral trap generation is probably associated with the hole transport process in the oxide.
Facet Formation in Selective Silicon Epitaxial Growth
Authors: Ishitani Akihiko , Kitajima Hiroshi , Endo Nobuhiro , Kasai Naoki
Published: November 2005

Facets observed adjacent to insulator films in selective silicon epitaxial growth were studied. The facet formation depended on the crystallographic orientation of the openings, and facets did not appear adjacent to the SiO2 sidewall parallel to the [100] direction. Facet formation could also be suppressed by using a polysilicon-coated sidewall. Defects in the selective epi-layers were examined using transmission electron microscopy, and facet-free and defect-free epilayers were obtained.
New Techniques for Growing Highly-Homogeneous Quaternary Hg1-x-yCdxMnyTe Single Crystals
Authors: Takeyama Shojiro , Narita Shin-ichiro
Published: November 2005

An advanced crystal growth method named the “modified two-phase mixture method” has been developed as a new way of producing highly-homogeneous large single crystals of quaternary semimagnetic semiconductor Hg1-x-yCdxMnyTe alloys. A comparison of the results with the usual Bridgman method and the modified zone melting method shows that the new method gives the best homogeneity in the growth direction and is promising for the crystal growth of multinary compound semiconductors with temperature-composition phase diagrams having a wide separation of the liquid and solid phase mixtures.
Transmission Electron Microscopic Observation of Microdefects in Zn+-Implanted GaAs
Authors: Morita Etsuo , Kasahara Jiro , Kawado Seiji
Published: November 2005

Transmission electron microscopic (TEM) observation of GaAs implanted with 100 keV Zn+ ions to 1014 ∼1015 ions/cm2 and annealed at 650 ∼950^°C by capless annealing in As ambient revealed precipitates, stacking-fault tetrahedra (SFTs) and stacking-fault pyramids (SFPs). The precipitates, distributed from near R
p to greater depths, consisted of non-crystalline material of mean inner potential smaller than that of GaAs. Defects showing black-white contrast were found to be SFTs accompanied by a precipitate or SFPs. Two types of SFTs can be differentiated by the core structure of their stair-rod dislocations. Most of the SFTs observed were identified as β-SFTs, and very few SFPs were observed.
Analysis of Capacitive Coupling Voltage Contrast in Scanning Electron Microscopy
Authors: Watanabe Yoshio , Fukuda Yukio , Jinno Takamitsu
Published: November 2005

The capacitive coupling voltage contrast occurring when a low-energy electron beam is directed on to a passivated LSI device in scanning electron microscopy disappears with increasing electron irradiation, and the secondary electron (SE) signal intensity varies proportionally with the surface potential. The experimental contrast variation of the capacitive coupling voltage in the buried electrode is analyzed theoretically. The calculated results on the SE signal intensity agree well with the experimental ones.
Fabrication of Diamond-Glass Composite under Micro-Gravity
Authors: Noma Tatsuo , Sawaoka Akira
Published: November 2005

Glasses containing a dispersion of diamond-particles were fabricated under micro-gravity and 1 G. Under micro-gravity, as the wettability between the sample and specimen capsule was significant, part of the fused specimen leaked out of the capsule. However, the microstructures and mechanical properties of the specimens fabricated in space were more isotropic than those of the samples fabricated under 1 G, and the particles were dispersed more homogeneously.
Growth and Characterization of Liquid-Phase Epitaxial Bi-Substituted Iron Garnet Films for Magneto-Optic Application
Authors: Hibiya Taketoshi , Morishige Yukio , Nakashima Junichiro
Published: November 2005

The effects of the chemical species of host rate-earth ions, melt compositions and growth orientations on the Bi-substitution level and magneto-optic properties of Bi-substituted garnet films grown by liquid-phase epitaxy were examined. For Gd3+ ions, a higher level of Bi substitution was attained than for Y3+ or Lu3+ ions, when garnet films were grown under the same growth conditions. A maximum Faraday rotation coefficient of -2880°/cm at 1.30 µm was observed in the (GdBi)3(FeAlGa)5O12 film with a Bi-substitution level of 1.56 moles per garnet formula unit. The optical absorption coefficient was as small as 1.6 cm-1 in the (GdBi)3(FeAlGa)5O12 film with a Faraday rotation coefficient of -1800°/cm; consequently, a figure of merit of 267°/dB was attained at 1.30 µm.
NMR Study of Hydrogen Adsorbed on Copper-Nickel Alloys
Authors: Ito Taro , Shibanuma Takashi , Kadowaki Toru
Published: November 2005

The adsorption states of hydrogen on Cu100-x
Ni
x
(x=0 ∼10) alloys were studied by nuclear magnetic resonance NMR, and the proton resonance shift was found to decrease and the line width to increase with increasing Ni concentration x. Steep changes in the shift and the line width were observed in the range of low Ni concentration (x<1). The decrease in the shift is attributable to the rapid exchange of H adatoms between sites in the Cu environment and sites of Ni or Cu atoms in contact with the Ni atoms. Since H adatoms on the latter sites are spin-polarized by Ni 3d-electrons via conduction s-electrons, their shifts are smaller than those for H adatoms on the former sites.
Phonon Scatterings of Quasi Two-Dimensional Electron Gas in a Single Heterostructure
Authors: Polonovski Jean-Pierre , Tomizawa Kazutaka
Published: November 2005

The wave functions and energy levels of quasi two-dimensional electron gas in a single heterostructure are evaluated by a variational technique. The scattering rates of quasi two-dimensional electron gas due to the acoustic, non-polar optical and polar optical phonons are calculated by using the wave functions thus obtained.
Two-Phase Structure of a-Si1-xNx:H Fabricated by Microwave Glow-Discharge Technique
Authors: Chayahara Akiyoshi , Ueda Masato , Hamasaki Toshihiko , Osaka Yukio
Published: November 2005

Amorphous Si1-x
N
x
:H films (x \lesssim0.1) were made by the microwave discharge technique. At x less than 0.05, both the activation energy E
a of the conductivity σ and the optical energy bandgap E
op of a-Si1-x
N
x
:H films were almost constant, while σ decreased rapidly with increasing x. It is predicted from the intensity variation of the Si-H stretching modes as a function of x that the film consists of mixed phases of a-Si and a-Si3N4, and that E
op and E
a are determined by the a-Si phase.
Mechanical Relaxation of Poly (Vinylidene Fluoride) and Copolymer of Vinylidene Fluoride and Tetrafluoroethylene in α and β Relaxation Regions
Authors: Abe Yoshio , Kakizaki Maeko , Hideshima Teruo
Published: November 2005

From torsional stress relaxation measurements on two kinds of poly (vinylidene fluoride) (PVDF) and a copolymer of vinylidene fluoride (VDF) and tetrafluoroethylene (TFE) between -80°C and +90°C, three relaxations are found and named α2, α1and β in order of descending temperature. The activation energy and relaxation spectrum are determined by the method of reduced variables. It is concluded that the β relaxation is caused by the micro-Brownian motion of amorphous chains, considering the temperature dependence of the relaxation time. The relaxation characteristics of the α1and α2relaxations for PVDF, VDF-TFE copolymer and polyethylene are shown to be very similar and to be independent of the difference in chemical structure. The α1and α2relaxations in these polymers are thus thought to be caused by the same molecular mechanisms.
Electrostrictive Properties of a PMN Stacked Actuator
Authors: Nakajima Yoshihiro , Hayashi Teru , Hayashi Iwao , Uchino Kenji
Published: November 2005

This paper reports a precise investigation of the fundamental electrostrictive properties of a Pb(Mg1/3Nb2/3)O3-based ceramic stacked actuator, including the local distribution of the strain induced in the sample, the bias voltage dependence of the effective piezoelectric coefficient, the response speed of the displacement to an applied voltage, and the dependence on pressure and temperature. It was found that an applied voltage deforms the stacked actuator non-uniformly in an arc contour on the driving face. The 7 mm-thick device can generate a displacement up to 8.5 µm under a voltage of 1 kV with a 10 µs response. The maximum generative force reaches 1.7×104 N for a driving area of 3.8 cm2.
A New Constant Deviation Monochromator for Angle Resolved Photoemission Spectroscopy
Authors: Miyahara Tsuneaki , Suzuki Shoji , Hanyu Takaaki , Kato Hiroo , Naito Kenzo , Fukutani Hirohito , Nagakura Ichiro , Sugawara Hidenao , Nakai Shun-ichi , Ishii Takehiko , Noda Hideyuki , Namioka Takeshi , Sasaki Taizo
Published: November 2005

A new type of constant deviation monochromator equipped with three interchangeable concave gratings (600, 1200 and 2400 grooves/mm) of 2 m radius of curvature was designed and built specifically for angle resolved photoemission spectroscopy at photon energies ranging from 20 to 160 eV. The exit slit of the monochromator is at a fixed position, whereas the entrance slit moves, simultaneously with grating rotation, along the direction of the incident light so as to minimize the amount of defocusing. A monochromatic light spot of 0.5 mm in diamter was obtained at the fixed sample position with the aid of a toroidal postfocussing mirror. It is found over the energy range concerned that the resolution is bettern than 1700 with 25 µm slits, and the photon flux obtained behind the toroidal mirror for a horizontal acceptance angle 0.5 mrad is 4×1010 photons/s when the width of the slits is 50 µm and the stored current for synchrotron radiation is 100 mA.
Nonequilibrium Hydrogen Plasmas in Microwave Fields by Two-Temperature Model
Authors: Ohguchi Yasutomo , Satonaka Takayoshi , Kaneko Takenori
Published: November 2005

Hydrogen plasmas in microwave discharge at 1.0 atm are studied with the two-temperature model, and are compared with local thermodynamic equilibrium plasmas and with two-temperature plasmas of dc discharge. There are two kinds of stable states: one in a lower power region (region-I) and the other in a higher power region (region-II). The plasma in the region-I is the same as the glow plasma of dc discharge. In region-II, electron and gas temperatures at the axis decrease with increasing dissipated power per unit length, because the column radius increases owing to the skin effect. In the lower part of the region-II, the plasma is filamentary. The temperature profiles in the region agree with the results measured by Arata et al. In the higher part of the region-II, the electron temperature in the outer area is higher than that in the intermediate area.
A High-Temperature X-Ray Lang Camera
Authors: Mizuno Kaoru , Kino Takao
Published: November 2005

A high-temperature X-ray Lang camera has been designed to examine metal single crystals with a low dislocation density during the heating or cooling processes. The furnace for the camera was set on a goniometer-hand, therefore the setting of specimen is only slightly restricted. The camera can be used to take a topograph at any temperature up to 500°C with desired heating or cooling run. The spatial gradient of temperature in the exposing area of the specimen is less than 1°C/mm, and the fluctuation of temperature during an exposure of about 30 hours is less than ±0.5°C. Using this camera, several topographs were taken during a heating process of high purity aluminum single crystal. As the result it was ascertained that a screw dislocation converts to a helical dislocation by the generation of vacancies during the heating process.
On the Mechanisms of Lateral Solid Phase Epitaxial Growth of Amorphous Si Films Evaporated on SiO2 Patterns
Authors: Yamamoto Hiroshi , Ishiwara Hiroshi , Furukawa Seijiro
Published: November 2005

Mechanisms of the lateral solid phase epitaxial (L-SPE) growth of amorphous Si films, which were vacuum-deposited on (100)Si substrates with SiO2 patterns, are investigated using experimental data from cross-section transmission electron microscopy and other techniques, and results are compared with theory. In the case of the L-SPE growth along the [011] direction, it is concluded that the (111) facet is formed at the SiO2 pattern edge during the vertical SPE stage and the L-SPE proceeds from the facet plane by microtwin-accelerated growth. For the growth along the [010] direction, it is found that the (110) facet plane is formed during the vertical SPE stage but changes to the folded {111} facet planes during the initial L-SPE growth. Growth models in the L-SPE along both directions are also presented.
Dust-Effect Reduction Facility of a Digital Correlator for Dynamic Light Scattering
Authors: Soda Kunitsugu , Nishio Izumi , Suzuki Naohito , Wada Akiyoshi
Published: November 2005

A minicomputer-assisted digital correlator for dynamic light scattering (DLS) measurement has been made. The correlator has a unique circuit construction to minimize the effect of dust particles in sample solutions. Detailes of the operation of electronic circuits assuring the dust-effect reduction facility are described. An example of the measurement of DLS correlation functions for solutions of polystyrene latex spheres is presented demonstrating the correlator's performance.
Low-Temperature Ti-Silicide Forming Reaction in Very Thin Ti-SiO2/Si(111) Contact Systems
Authors: Iwami Motohiro
Published: November 2005

Very thin (\lesssim4 nm) titanium films were deposited on Si(111) surfaces with very thin (1–4 nm) oxide, SiO2, layers on top in a UHV system at room temperature. Ti-films with oxygen inclusion did not react at room temperature, but annealing at \lesssim350^°C induced the formation of a TiSi2 layer between the Ti-film and the SiO2-layer. On the other hand, Ti-film without oxygen inclusion induced a small but definite SiO2-reducing reaction at the Ti-SiO2 interfaces even at room temperature. The amount, or thickness, of the TiSi2 layers formed between the Ti- and SiO2-layers could be controlled by varying either the amount of titanium deposited or the annealing temperature.
Formation of Shallow p+n Junctions by B-Ion Implantation in Si substrates with Amorphous Layers
Authors: Ishiwara Hiroshi , Horita Susumu
Published: November 2005

The optimum conditions to form shallow p+n junctions by B-ion implantation in Si substrates were investigated. In order to avoid a deep penetration of the B ions, they were implanted in amorphous Si(a-Si) layers on Si(100) substrates. These substrates were produced by either the pre-implantation of Si ions or the vacuum-deposition of Si and were annealed in an electric furnace at 650°C or by a scanning electron beam (EB) It was found that the defects existing near the original amorphous-crystalline interface were not annealed out by low-temperature furnace annealing or EB annealingand that the reverse current of the pn diode drastically increased when the interface was located in the depletion layer of the junction. Shallow p+n junctions with good electrical properties were obtained when the thicknesses of the deposited a-Si films were a little thinner than the junction depths.
Cluster Beam Production by a Slit-Throat Nozzle
Authors: Be Suck Hee , Yano Katsuki
Published: November 2005

A nozzle with a slit-throat, capable of producing a cluster beam of a high total flux while keeping the cluster size constant, was constructed, The basic idea underlying this new type of nozzle is that a slit-throat nozzle is equivalent to a linear array of axisymmetric nozzles of diameter qual to the throat width. A comparison between experimental results with both this nozzle and a trumpet-shaped nozzle showed that the cluster size produced with the same nozzle-source parameters, such as temperature and pressure, is limited by the width of the slit-throat and that the total flux increases inproportion to its length. A comparison between the experimental results and calculations based on the classical condensation theory was also performed.
Liquid Hydrogen and Deuterium Target for Antiproton Annihilation at Rest
Authors: Kobayashi Masaaki , Suzuki Shoji , Doi Yoshikuni , Morimoto Kimio , Fujitani Takeo , Omori Tsunehiko , Sugimoto Shojiro , Yamaguchi Yoshitake , Chiba Masami
Published: November 2005

A 3.3 l liquid hydrogen and deuterium target cell of diameter 140 mm and length 230 mm constructed from 0.2 mm-thick stainless-steel sheet was used for an experiment on the annihilation of antiprotons at rest in the KEK 12 GeV Proton Synchrotron. The target cell was mounted deep inside the detector system, and the whole target system was designed for safety in case of breakage of the target cell, because the detector was contained in an enclosed room. The liquid level in the cell could be monitored well with carbon resistors distributed on its outer surface.
Current Peaks Following Voltage Reversal in Chlorinated Polyethylene
Authors: Iida Kazuo , Ishiguro Haruchika , Nakamura Shuhei , Ieda Masayuki , Sawa Goro
Published: November 2005

Two peaks, a primary (P1) and a secondary (P2), are found in the voltage-reversal current in chlorinated polyethylene with Au-Au electrodes. Since the time to each peak is inversely proportional to the electric field after the voltage reversal, the two peaks are related to the transit times of two different kinds of ion between the electrodes, and the corresponding mobilities can be estimated from these transit times. A consideration of the free volume and the effect of polarity on the voltage-reversal current with Au-Al electrodes, leads to the conclusion peaks P1 and P2 originate from negative and positive ions, respectively. These ions are probably Cl- and H3O+, respectively.
Superconductive Granular Thin Film and Phase Quantum Tunnel Device
Authors: Sugahara Masanori
Published: November 2005

Theoretical considerations show that superconductive granular films can be classified into two groups; \varTheta-superconductors with a definitive phase and N-superconductors with a definitive particle number. It is pointed out that a device made of an N-supercnductor has properties conjugate to the Josephson effect.
Upper Critical Fields in Ternary Superconducting Ti-Nb-Ta Alloys
Authors: Sasaki Takao , Noto Koshichi , Muto Yoshio
Published: November 2005

We have measured the temperature dependence of the upper critical field H
c2 in the Ti66Nb34-x
Ta
x
(x=0, 6, 20) alloy system, where Nb is substituted for a higher atomic number element, Ta. An alloy containing 6 at.% Ta exhibits a higher critical field than the binary alloy Ti66Nb34 in the temperature range below 4.2 K. The mechanism of the enhancement of the critical field at low temperature is studied in relation to the spin-orbit scattering effect. The spin-orbit scattering parameters λso for Ti66Nb34, Ti66Nb28Ta6 and Ti66Nb14Ta20 are estimated to be 1.1, 2.8 and 4.1, respectively, keeping the Maki parameter, α=1.8±0.05, constant.
An ESR Saturation Treatment for Solvated-Electron Systems
Authors: Hiromitsu Ichiro , Hase Hirotomo , Higashimura Takenobu
Published: November 2005

ESR saturation measurements of solvated electrons (esol
-) in alkaline ices were carried out at 73 K and 4 K. When there was no cross-relaxation for esol
-, the observed line widths of esol
- did not agree with those calculated by Zhidkov's treatment. The larger spin-packet width found at 73 K than that at 4 K was interpreted in terms of spectral diffusion. When cross-relaxation occurred between esol
- and neighbouring radicals, the line widths of esol
- were interpreted as being due to both the spectral diffusion and the cross-relaxation. A more comprehensive treatment including a cross-relaxation time is presented; this treatment succeeds in fitting the observed line widths to the theoretical ones.
Short-Lifetime Measurement of Molecules in the Vacuum Ultraviolet Using High-Resolution Laser Spectroscopy
Authors: Maeda Mitsuo
Published: November 2005

A measurement system of short radiative lifetimes of molecules at high spectral resolution in the vacuum ultraviolet (VUV) region is developed. Tunable VUV radiation is generated by the four-wave sum-frequency mixing method in Mg vapor. A specially-designed dye-laser system with short pulse duration (less than 2 ns) is used. Individual rotational levels of CO A1Π(v' =0, 1) are excited and the fluorescence decay times are measured down to 5 ns with a spectral resolution of 0.3 cm-1.
An Optical Fiber Thermo-Sensor Using GaP
Authors: Takeo Takashi , Hattori Hajime
Published: November 2005

An optical fiber thermo-sensor utilizing the temperature dependence of the energy gap (E
g) of GaP is proposed. The absorption-edge wavelength of GaP is about 550 nm, and its temperature shift is less than that of the GaAs or CdTe used in previous studies, suggesting that a sensor using GaP will be compatible even with plastic fibers and have a wide dynamic range with respect to temperature.
Sensors made from Zn-doped or epitaxially-grown GaP were also investigated with the aim of obtaining a broader dynamic range and higher sensitivity to temperature. The response time and measurement accuracy of the trial sensor were 2 s and within ±1°C, respectively. A local network system with a ring-configuration is demonstrated as an application of the sensor.
Electron Mobility and Drag Effect in p-Type Silicon
Authors: Morohashi Makoto , Sawaki Nobuhiko , Akasaki Isamu
Published: November 2005

The drift mobility of electrons in p-type silicon containing acceptor concentrations from 1.4×1013 cm-3 to 5.8×1015 cm-3 was measured by the time-of-flight technique. The experiments were carried out at temperatures from 77 K to 300 K by applying electric fields between 25 V/cm and 700 V/cm. In the ohmic region, a large reduction in mobility was observed below 150 K in low-resistivity samples. By applying Mclean and Paige's theory, it was found that this reduction is due to the drag effect by the majority holes. In the warm electron region, the mobility of electrons was found to be smaller than that for an intrinsic material. This is the first observation of the enhancement of the drag effect of the electric field.
Changes in Physical Properties and Electrochromic Characteristics of Atmospheric-Evaporated Tungsten-Oxide Films (AETOF)
Authors: Morita Hiroshi
Published: November 2005

The reasons for changes in the electrochromic characteristics of atmospheric-evaporated tungsten-oxide films (AETOF) were investigated, and significant lowering of the electrochromic response was found in cells utilizing films stored in air. This lowering was found to be due to oxidation of the film surface. Etching off the surface layer is an effective method of improving stored film.
A Stable High-Brightness Electron Gun with Zr/W-tip for Nanometer Lithography. I. Emission Properties in Schottky- and Thermal Field-Emission Regions
Authors: Samoto Norihiko , Shimizu Ryuichi , Hashimoto Hatsujiro , Tamura Nobuaki , Gamo Kenji , Namba Susumu
Published: November 2005

A Zr/W-tip consisting of a <100 >-oriented tungsten emitter with an overlayer of zirconium was mounted in a new electron gun system designed for the basic study of nanometer lithography, and the emission properties of the tip were investigated. The tip performed excellently, exhibiting a brightness of ∼2×108 A/(cm2·sr) at 50 kV, a current stability of less than 0.2%/h, and an angular current density of ∼3.4 mA/sr at 20 kV. The work function of the Zr/W-tip operating in the Schottky emission region was roughly estimated as 3.2 eV.
One-Directional Grain-Oriented Lead Metaniobate Ceramics
Authors: Nagata Kunihiro , Okazaki Kiyoshi
Published: November 2005

One-directional grain-oriented lead metaniobate ceramics were obtained by a combination of molten salt synthesis and two-stage hot-pressing. The powder characterization and the microstructural, dielectric and piezoelectric properties of the ceramics were measured and are discussed here. Long needle-shaped powders of lead metaniobate were prepared by molten salt synthesis at 1050°C for 5h using a KCl flux, and the crystal structure was orthorhombic. Anisotropies of about 4 times in the permittivities and the coupling factors were found between the directions parallel and perpendicular to the hot-pressing direction in the uniaxially grain-oriented ceramics.
Characterization of Interface Instability in InGaAsP LPE Growth on GaAs by Fourier Analysis
Authors: Hiramatsu Kazumasa , Tanaka Shigeyasu , Sawaki Nobuhiko , Akasaki Isamu
Published: November 2005

Using the Fourier spectrum of the surface morphology, the morphological instability occurring in the hetero-structure of In
x
Ga1-x
As
y
P1-y
(y<0.01) LPE layers on (100)GaAs substrates grown under supercooling of less than 1°C was studied in relation to the undersaturation Δ
T and the growth time t
g. The Fourier analysis enabled the instability to be investigated quantitatively, and it was found that the wave number for the rippled structure is distributed over a certain range. The average value of the wave number depends on the time as t
g
-1/3 and its power intensity depends strongly on Δ
T as an exponential function. The Ostwald growth process suggests that this instability is due to diffusion of the solutes, decreasing the interfacial free energy due to the interphase surface tension.
Determination of Atomic Hydrogen Density by Lyman-Alpha Laser Fluorescence Spectroscopy
Authors: Kajiwara Toshinori , Inoue Masayuki , Okada Tatsuo , Maeda Mitsuo , Muraoka Katsunori , Akazaki Masanori
Published: November 2005

Atomic hydrogen densities and their detection limit were determined accurately by vacuum ultraviolet laser fluorescence spectroscopy, tuned to the Lyman alpha line, using the third harmonic generation of a tunable dye laser pumped by a XeCl excimer laser as the excitation source. A well-characterized atomic hydrogen source, whose absolute density was measured by absorption, was used to assess the detection capability of the laser fluorescence spectroscopy, which gave absolute density determinations to within ±30% and a detection limit of 3×1015 m-3.
New Simulation Model for Perpendicular Recording Co-Cr Medium
Authors: Iijima Akemi , Shiiki Kazuo , Shinagawa Kiminari
Published: November 2005

Numerical analysis of a Co-Cr medium-ring type head system for perpendicular recording are performed using a two dimensional model with a finite element method. A new magnetization model of the Co-Cr medium is proposed, a columnar structure being taken into consideration. The medium is divided into elements for the calculation and an additional field, Had∝( Mupper+ Mlower) is assumed to be applied from upper and lower elements within a column, where M is the magnetization of the element. The results of the simulation show that the interaction between elements plays an important role in the magnetization process of the Co-Cr medium.
Optical Spectral Change in Conducting Polymer Due to Insulator-Metal Transition Induced by Light Irradiation and Proposal As Optical Memory Element
Authors: Yoshino Katsumi , Sugimoto Ryu-ichi , Rabe Johan Georg , Schmidt Werner Fritz
Published: November 2005

By the irradiation of light on the conducting polymer like polythiophene doped with diaryliodonium salts, its absorption spectrum changes remarkably, which can be explained in terms of an insulator-metal transition due to light induced doping. The application of this phenomenon as an optical memory element which can be written by the light irradiation, is proposed.
Characteristics of the Detectors for Bolometric Measurement in Application to High Temperature Plasma
Authors: Ogawa Isamu , Kawahata Kazuo , Noda Nobuaki , Watari Tetsuo , Tanahashi Shuugo , Toi Kazuo , Fujita Junji
Published: November 2005

The characteristics of a thermistor, a metal-film bolometer, and a pyroelectric detector were investigated with the aim of attaining a highly reliable bolometric measurement. The spurious signal which appears on a pyroelectric detector was sufficiently eliminated by setting a mask close to the detector, thus avoiding the direct incidence of photons at the electrode. Whether a signal was true or false could be determined from the integrated value of the signal. Calibrations were performed with a HeNe laser in consideration of reflections on the detector surface. No time drift was observed on the sensitivity determined in such a way. The radiation power measured with a pyroelectric detector agreed within 10% with that measured with a calibrated metal-film bolometer.
Prolate Tetragonal Anvil-Type High-Pressure Apparatus
Authors: Nomura Motoyuki , Hirai Tokuyuki , Kuroda Keigo , Fujiwara Hiroshi
Published: November 2005

A prolate tetragonal anvil, which enables an extension of the pressure chamber without a loss in the generated pressure was proposed and actually built. The necessary condition for an isotropic compression of the pressure medium was deduced. The observed deformation of the pressure medium was, however, rather nonuniform and the pressure medium was slightly elongated along the direction of the press ram load. The generated pressure, on the other hand, was slightly increased compared with a cubic anvil apparatus having the same size anvil top as that in the direction of the press ram load, probably due to a reduction in the friction between the anvil holder and the sliding plane. The system of a rectangular noncubic hexahedron anvil in which the influence of the friction is taken into consideration is also proposed.
Analyses of ICRF Waves on JET Plasma
Authors: Itoh Sanae-Inoue , Itoh Kimitaka , Fukuyama Atsushi
Published: November 2005

A theoretical and a computational study of ICRF waves were conducted for JET plasma. The present experimental parameters are analysed and various prediction studies for future experiments are considered using a combination of two kinetic codes. The wave field was solved for obtaining a power deposition profile of each plasma species and the antenna impedance. A two-ion hybrid case was simulated. Strong minority heating in the central core region was observed and a direct input to electrons was found at most 10% of the total absorption. However, for the higher-temperature target plasma, the deposition profile to the electrons became broader and the off-center and its input reached 30%. An efficient non-central deposition to ions by a combined use of NBI is also discussed. A global coupling study is also given for a cold plasma with dampings.
Improved Use of Görlich Photocathodes in the Lasertron
Authors: Kuroda Hiroto , Nakano Noboru , Hora Heinrich
Published: November 2005

The next generation of particle accelerators will require the development of powerful microwave radiation sources, in addition to the use of free electron lasers for high microwave fields or various concepts of laser acceleration of particles. One of these concepts is the lasertron in which recent experimental studies indicated limitations by pre-discharges at the photoemitter irradiation by a mode locked laser. Improvements are discussed within the framework of the accelerator requirements of efficiency and cost. The possibility of two-photon emission, the reduction of the involved surface traps (increasing the exit potential of the cathodes) and alternative production of a Cs3Sb compound for the Görlich cathode using the chemistry of water-like solvents as liquid ammonia is evaluated.
Magnetic and Crystallographical Characteristics of the Sendust Films formed by DC Opposite Sputtering Method
Authors: Miura Michiyori , Tanaka Katsuyuki , Noro Yoshihiko
Published: November 2005

Sendust films were formed using DC opposite sputtering equipment. Then, sputtering conditions that influcne the magnetic and crystallographical characteristics of the films were studied. Sendust films with a low coercive force (< 1 Oe) and a high initial permeability (> 1000 at 6 MHz) are formed under the conditions of high sputtering gas pressures and high substrate temperatures. As the deposition rate increases, a higher substrate temperature is necessary to form films with low coercive forces. Superlattice formation and large columnar crystallites are found in the films formed at high sputtering gas pressures and high substrate temperatures; they decrease the coercive forces of the films.
Effects of Light Impurities on Electron Temperature Measured by Soft X-Ray Filter Method
Authors: Morimoto Shigeyuki , Okamoto Shingo , Yanagi Nagato , Iiyoshi Atsuo , Uo Koji
Published: November 2005

The power of soft X-rays filtered by thin (thickness < 10 µm) aluminum absorbers was calculated for hydrogen plasma contaminated by light impurities. The impurities strongly enhance the radiation power but do not appreciably change the ratio of the signals through two filters of different thickness. The filter (or ratio) method can therefore be used to estimate the electron temperature in the presence of the impurities.
Temperature Range for DFB Mode Oscillation in 1.5 µm InGaAsP/InP DFB Lasers
Authors: Matsuoka Takashi
Published: November 2005

The temperature range for distributed feedback (DFB) mode oscillations in 1.5-µm InGaAsP/InP DFB lasers was investigated. The range was determined by the relation between the net gain spectra and the loss difference between the Fabry-Perot and DFB modes. The temperature dependence of the net-gain spectra of 1.5-µm InGaAsP/InP Fabry-Perot (FP) lasers were measured. The loss difference between FP and DFB modes was calculated while taking into account the corrugation phase at facets, the facet reflectivity, and the coupling coefficient. From these results, it is confirmed that DFB lasers with two cleaved facets and a κL value of 2(κ: coupling coefficient, L: cavity length) can oscillate in the DFB mode in a temperature range of at least 100 degrees.
Synthesis and Characterization of Amorphous Si-Zn-S Alloy Films
Authors: Morimoto Akiharu , Shimizu Tatsuo
Published: November 2005

Hydrogenated amorphous Si-Zn-S films were synthesized by means of radio-frequency magnetron sputtering of Si, ZnS and Zn composite targets. The infrared absorption, the Raman scattering, the optical absorption, the electron-spin resonance, the photoconductivity and the electron probe microanalysis measurements were carried out for both asdeposited and annealed films. It was found that Zn and S atoms in as-deposited film tend to form Zn-S bonds rather than metallic Zn clusters and S clusters. However, so far we have not obtained hydrogenated amorphous Si-Zn-S films with high photoconductivity.
Bonds and Defects in Plasma-Deposited Silicon Nitride Using SiH4-NH3-Ar Mixture
Authors: Makino Takahiro , Maeda Masahiko
Published: November 2005

The compositions, structures and defects in silicon nitride films are investigated by chemical analyses, infrared absorption, electron spin resonance and breakdown strength. Even in N-rich silicon nitride, N-N bonds are hardly formed; this is in contrast with Si-Si bond formation in Si-rich films. High-temperature annealing causes a degradation of the breakdown strength for N-rich and Si-rich films, but has little effect on stoichiometric and slightly Si-rich films. Little correlation has been found between the degradation of the breakdown strength and ESR active Si dangling bonds. To explain these results, a defect model proposed by Robertson and Powell is applied to Si- and N-rich silicon nitride as well as to a stoichiometric film.
Electronic Properties of Cs-Covered Surfaces of Graphite (0001)
Authors: Okuyama Naoki , Yamazaki Masahito , Tomita Kazushi , Yasunaga Hitoshi
Published: November 2005

The electronic properties of Cs-covered graphite surfaces were studied by low-energy electron diffraction, Auger-electron spectroscopy and work function measurements. The behaviors of an additional structure appearing with the adsorption of Cs on the high-energy side of the C KVV (272 eV) Auger spectra are interpreted in terms of the density of states (DOS) of the graphite π conduction band and the extra DOS induced by the alkali atom. The change in work functions is ascribed to a Fermi-level shift due to charge transfer from the Cs to the graphite π conduction band and the potential difference between the graphite surface and the Cs overlayer. Examination of the work function shows that the charge transfer per adsorbate is unity up to a relative coverage of θ=0.35 and thereafter decreases monotonically to a value of 0.35 at the full coverage θ=1.
Determination of Diffusion Coefficients of Self-Interstitials in Ice with a New Method of Observing Climb of Dislocations by X-Ray Topography
Authors: Goto Kumiko , Hondoh Takeo , Higashi Akira
Published: November 2005

The diffusion coefficients of self-interstitials in ice were determined from the growth processes of interstitial-type dislocation loops and dipoles introduced by cooling on the basis of the fact that the growth takes place by the diffusion of excess interstitials to dislocations. The time variation of their size was obtained by in situ X-ray topographic observations using a high-power X-ray source. By combining the obtained diffusion coefficients and the equilibrium concentration of interstitials previously obtained, it is possible to determine the self-diffusion coefficient D
s in ice. The value of D
s obtained by this method and its activation energy E coincide well with those determined by tracer experiments. This result confirms the interstitial mechanism for self-diffusion in ice.