bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies On Ionization Coefficients of Targets in an Amorphous Selenium APD for Pick-up Tubes by New Type Least Squares
Authors: Taketoshi Kazuhisa , Tanioka Kenkichi , Kawamura Tatsuro
Published: November 2005

The ionization coefficients of electrons and holes (i.e. α and β) have been determined only by the voltage and current characteristics of targets of a-Se APD in the operation state of pick-up tubes. These determinations were based on selfconsistently solving 12 simultaneous transcendent Webb's equations by using random numbers and linear approximations.
The values obtained for β and α(1/cm) varied from β=7.36×106 exp
(-8.24×106/E) and α=8.09×102 exp
(-0.04×106/E), to β=24.6×106 exp
(-9.80×106/E) and α=3.60×102 exp
(-0.11×106/E) (unit of E; V/cm). The excess noise factor (K') for a gain equaling 10 varied from 2 to 3. The differences in the obtained values were attributed to differences in sample histories.
Many FIR Laser Emissions Pumped by a TEA-C02 Laser with Etalon Tuning
Authors: Nishi Yoshio
Published: November 2005

Using the pumping light of a TEA-C02 laser with etalon tuning, we have observed more than 90 new FIR laser lines from CH3OH, CH2Cl2, C2H5OH, CF3Br, HCOOH, and D2O.
These new lines are obtained from effective excitations using an etalon, which enables us to operate the TEA-CO2 laser as a tunable source with single-mode emission.
Furthermore, it has been found that many FIR laser lines which were previously reported only with cw-CO2 laser pumpings also oscillate for CH3OH, HCOOH, CH3Br and CH3I.
These lines and the newly discovered lines are the results of using an FIR resonator of more than 3 m in length which has a high Q-factor. The Q-factor can be calculated based on the waveforms of Raman FIR laser emissions from NH3. The waveforms are in good agreement with theoretical predictions.
Metal Film Sputtering Technique to Coat Teeth for Preventing Dental Caries. A Preliminary Study
Authors: Sugita Toshio , Ebisawa Shigeo , Nishikawa Eiichi , Morinushi Takanobu , Hanashima Shigeharu
Published: November 2005

Dental caries starts locally on a tooth surface; thus, the selective protection by metal films on pits and fissures is simple and effective. The method and apparatus for forming preventive coatings by sputtering are described wherein metal atoms originate in a Penning discharge space and are then guided through a duct in order to reach a tooth and then to form a spot coating on the surface. A compact-size sputtering apparatus for the coating of a gold film on a surface of extracted teeth or glass substrates has been designed and the film-deposition characteristics examined. The typical deposition rate is 1 nm/s for a 6-mmφ film on a glass substrate. After gold films are coated on extracted teeth, the teeth are immersed in an 0.1 mol lactic acid solution (pH=4.0). The obtained results indicate that a thickness of about 200 nm is necessary and satisfactory for protecting against dental caries in vitro.
Birefringence-Modulated Polarization Spectroscopy
Authors: Nakayama Shigeru , Baird Patrick E.G.
Published: November 2005

The aim of this work was to develop a high-resolution, ultra-sensitive laser method that makes use of a Faraday modulator in a polarization spectroscopy arrangement. Though saturation spectroscopy is not a sensitive technique, polarization spectroscopy is a useful technique for obtaining both high resolution and high sensitivity. However, spectral line shapes are distorted. Our proposed birefringence-modulated polarization spectroscopy has additional advantages in sensitivity and symmetry of the line shape over saturation and polarization spectroscopy. The spectra of the sodium D1 line have been calculated in order to compare the various spectroscopic techniques.
Frequency Dependence of Raman Cross Section of CH4v1 Line Determined with Coherent Raman Spectroscopy
Authors: Taira Yoichi , Uchikoba Fumio , Takuma Hiroshi
Published: November 2005

A determination of the absolute Raman cross sections of gases using stimulated Raman gain or inverse Raman spectroscopy is discussed. These coherent Raman methods were applied to determine the absolute Raman cross sections of the v
1 line of gaseous methane at several visible pumping frequencies.
Space-Charge-Limited Currents in Insulators with Shallow Traps and Conductivity Distribution
Authors: Koda Norio
Published: November 2005

Current-voltage (J–V) characteristics are derived for the single injection current in insulators containing nonuniformly distributed conductivity and uniformly distributed shallow traps. The J–V curves are shown to possess rectificalion. The cause of this effect is explained as resulting from the fact that the distribution of the conductivity leads to the distribution of the effective shallow trap density.
Observational Study on the Dendritie Growth of Al–Mg Single Crystals by Real-Time X-Ray Topography
Authors: Kobayashi Tatsumasa , Kawabe Nozomu , Imura Toru
Published: November 2005

Real-time X-ray topography has been applied to a study of dendritic growth. Unidirectional melting and solidification processes of Al–Mg single crystals containing 0.5, 2.0 and 4.0 at%Mg were observed by real-time X-ray topography. Observations have been made on the following subjects: (1) sequential growth and morphology of dendrite arms during solidification as a function of the growth rate; (2) morphological changes of dendrite arms as a function of the Mg content; (3) morphological changes and solute redistribution during cooling and isothermal annealing after solidification; and, (4) observation of the melting process of a previously grown dendrite. Some valuable information which cannot be obtained by the conventional “ex post fact” method has been obtained by real-time X-ray topography.
Study on Electron Density Dependence of Metastable Ar+Density in Pulsed-Discharge Plasma by Using LIF Method
Authors: Watanabe Yukio , Shiratani Masaharu , Ogi Sukeomi , Kunihiro Naoki
Published: November 2005

The dependence of the Ar+metastable densityn(3d4F7/2) on the electron densityneand its radial profile were studied in the rangene=1014∼1015cm-3by using the LIF method in an Ar pulsed-discharge plasma. The measured LIF intensity was strongly affected by electron collisional quenching. The corrected LIF intensity was proportional to both then(3d4F7/2) estimated by a C–R model and the measuredne. Its radial profile agrees fairly well with thenemeasured by a double-probe.
Determination of Pitch Angles of Magnetic Field Lines in Tokamak with Obliquely Injected Helium Beam
Authors: Mohri Akihiro
Published: November 2005

The pitch angles of magnetic field lines or q-profile in a high-density tokamak can be determined by the new method proposed here. Blobs of monoenergetic helium beam with different velocities are injected into the tokamak obliquely to the toroidal direction on a poloidal plane χ. Produced He+ ions move nearly along magnetic field lines, and their front emitting a Hell line crosses a different sight plane and forms a curve on it. An optically measured shift of the curve from χ leads to a distribution of pitch angle after correction for the perpendicular drift motion of He+ ions, using the velocity dependence of the drift.
Electrical Properties of Iodine-Doped Nickel (Phthalocyanine) Films
Authors: Nakamura Shuhei , Amatatsu Hiroshi , Ozaki Tamon , Yamaguchi Shinji , Sawa Goro
Published: November 2005

The change in electrical conductivity of a vacuum evaporated nickel phthalocyanine (Ni(Pc)) film with doping of iodine has been studied based upon the analyses of the film structure, electronic spectroscopy, and electron spin resonance measurements. It was found that an abrupt increment of electrical conductivity at the first stage of incremental doping is accompanied by a phase transition from a monoclinic system to a tetragonal system. This phase transition causes cracks on the surface of film and leads to the collapse of the polycrystalline structure upon further doping. It is concluded that a gentle increase in the electrical conductivity with further doping is limited by the competitive process between the increment of charge carriers and the decrement of the electrical conduction path, and a collapse of the polycrystalline structure due to a phase transition.
Normal-Pressure and Low-Temperature Thermal Oxidation of Silicon
Authors: Zhang Hongyong , Kanoh Hiroshi , Sugiura Osamu , Oda Shunri , Uchida Yasutaka , Hattori Takeo , Matsumura Masakiyo
Published: November 2005

A new thermal oxidation method of silicon has been proposed and its feasibility has been demonstrated experimentally. Silicon-dioxide of 7 nm thickness was grown within 24 h at about 250°C by continuously supplying fresh nitric acid to a reaction tube under normal-pressure conditions. Detailed oxidation characteristics as well as the structure of the oxide are described. The oxide/semiconductor interface was changed from accumulation state to inversion state, and vice versa, by an application of the gate voltage. The minimum interface state density after 350°C annealing was about 2×1011 cm-2 eV-1.
Field-Induced Energy Shift of Excitonic Absorption in InGaAs/InP Multiquantum Wells Grown by Metalorganic Molecular Beam Epitaxy
Authors: Nojima Shunji , Kawaguchi Yoshihiro , Nakashima Kiichi , Wakita Koichi
Published: November 2005

Excitonic absorption features are observed at room temperature in InGaAs/InP multiquantum-well structures grown by metalorganic molecular beam epitaxy. The heavy-hole exciton peak was found to shift toward the lower-energy side as the result of an external electric field. These peak shifts showed good agreement with the results of an exact calculation using phase-shift analysis in the resonance-scattering theory for this quantum well.
Fill-Factor Calculation of Solar Cells Affected by Sheet Resistance of Surface Layer
Authors: Niu Hirohiko , Doi Hideki , Matsuda Tetsuro , Maeda Muneo
Published: November 2005

A calculation methoed for the fill factor or I–V curve of a solar cell with an active thin layer is developed. This method correctly estimates the power-consuming ability of the thin-layer sheet resistance, taking into account the lateral potential distribution in the thin layer, and can be applied to cells with any electrode shape. It has been shown that when using an equivalent series resistance by Handy's equations, the fill factor is underestimated.
Rotational Raman Scattering Using Molecular Nitrogen Gas for Calibration of Thomson-Scattering Apparatus
Authors: Yamauchi Yoshihiko , Nakazawa Ichiro
Published: November 2005

Anti-Stokes rotational Raman lines in molecular nitrogen gas were used for the calibration of Thomson-scattering apparatus. It was found that molecular nitrogen gas is suitable for a vessel having strong stray light. The polarization ratio was 0.16 using linear-polarized laser light.
Coloration of LiNbO3 by Metal Ion Implantation
Authors: Saito Yukinori , Suganomata Shinji
Published: November 2005

Various metal ions were implanted in LiNbO3. The optical absorption spectra were measured in the wavelength range from 400 to 700 nm. An X-ray photoelectron spectroscopy (XPS) analysis was performed on LiNbO3 implanted with Cu+ ions. The LiNbO3 implanted with Cu+ ions showed a blue-green color. The color was stable at low temperatures.
Cascade Fluorescences from Laser-Excited Lithium Atoms Immersed in a Static Electric Field for Plasma Diagnostics
Authors: Takiyama Ken , Kamiura Yoshitomo , Fujita Toshiaki , Oda Toshiatsu , Sakai Hisashi , Kawasaki Ken
Published: November 2005

The Stark effect on a laser-pumped Li atom to the 42D or 42F level was studied by the observation of two cascade fluorescences of 610.4 nm (32D→22P) and 323.3 nm (32P→22S) under a static electric field in order to develop a spectroscopic measurement of the static or quasi-static electric fields in plasmas with a combined technique of Li-beam probing and laser-induced fluorescence (LIF). The excitation spectra and field dependencies of both lines were obtained and found to agree with the theoretical values obtained by solving the rate equations. It was also shown that a method for exciting the forbidden transition from 22P to 42F is so sensitive as to make it possible to measure an electric field as weak as ∼ 100 V/cm. A practical method that is applicable to plasma devices is described, and the effect of the electron density on LIF is also discussed.
Determination of Twist Elastic Constant K22 in 5CB by Four Independent Light-Scattering Techniques
Authors: Toyooka Takehiro , Chen Guo-ping , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

The twist elastic constant K
22 in 5CB was determined as a function of temperature by the following four independent methods; (1) electric field static light scattering, (2) electric field dynamic light scattering, (3) angular dependence of the scattered light intensity combined with a K
11 or K
33 measurement, and (4) Frederiks transition detected by forced Rayleigh scattering. The first one is a measurement of relative scattered light intensity as a function of the applied voltage in a proper optical geometry, and was used to determine K
22 for the first time. Each measurement gave a K
22 value within an accuracy of ±4%. The collected values that were determined by the four methods were located within ±7% from each other. It was also confirmed that they agree with other recent measurements.
Characterization of a-Si:H Phase Transformation and Crystallization by Isothermal Annealing
Authors: Chou Jung-Chuan , Hsiung Shen-Kan , Lu Chih-Yuan
Published: November 2005

Hydrogenated amorphous silicon (a-Si:H) thin films have been prepared by plasma-enhanced low-pressure chemical vapor deposition (PE-LPCVD) from monosilane (SiH4) in hydrogen carrier gas. The variation of electrical conductivity with time at various isothermal annealing conditions have been used to study the phase transformation and crystallization kinetics. For the first time, it has been observed that the drop in the electrical conductivity in the early annealing stage is caused by hydrogen out-diffusion with different activation energies under various substrate temperatures. Transmission electron microscope (TEM) diffraction patterns, which directly measure crystallization, were also obtained. Furthermore, perpendicular crystallization rates for different activation energies under various substrate temperatures have been obtained. An empirical model to explain the phase transformation and crystallization kinetics of hydrogenated amorphous silicon thin films has been proposed.
Preparation and Properties of a-SiGe:H Films Fabricated with a Super Chamber (Separated Ultra-High Vacuum Reaction Chamber)
Authors: Haku Hisao , Sayama Katsunobu , Nakashima Yukio , Takahama Tsuyoshi , Isomura Masao , Tarui Hisaki , Hishikawa Yoshihiro , Tsuda Shinya , Nakano Shoichi , Ohnishi Michitoshi , Kuwano Yukinori
Published: November 2005

High-quality a-SiGe:H films with low impurity concentrations were studied using a separated ultra-high vacuum reaction chamber system called the super chamber. The ESR spin density and the tail characteristic energy of the a-SiGe films (E

o
p
t
1.5 eV) were 6.5×1015 cm-3 and 46 meV, respectively. These values were much lower than those for films fabricated in a conventional chamber as well as those for a-Si films. Structural properties, such as the refractive indices and thermal effusion of hydrogen, were also measured. The results suggest that impurity reduction contributed not only to an improvement in the optoelectrical properties, but also the formation of a rigid a-SiGe network.
Structural Studies on the ZrO2–Y2O3 System by Electron Diffraction and Electron Microscopy III
Authors: Suzuki Susumu , Tanaka Michiyoshi , Ishigame Mareo
Published: November 2005

The oxygen-ion displacements in modulated structures for 10–50 mol% Y2O3–ZrO2 can be assigned in terms of the frozen in distortions of the molecular vibrational modes of an oxygen ion cube. This assignment clarifies that the displacement of the 10 mol% Y2O3–ZrO2 structure type (a deformed fluorite structure) decreases and that of the Y2O3 structure type increases as the amount of Y2O3 increases. The displacement of the Y2O3 type already occupies 75% in 20 mol% Y2O3–ZrO2 and 97% in 50 mol% Y2O3–ZrO2 in the microdomains of modulated structures. The decrease of the ionic conductivity with the content of Y2O3 can be attributed to an increase in the volume of microdomains with the Y2O3-type displacement. The arc-shaped diffuse scattering observed in 20 and 40 mol% Y2O3–ZrO2 originates from the presence of various orientations and different intervals of the periodic antiphase boundaries.
High-Purity LPE Growth of InP by Co Addition to an In–P Melt
Authors: Kondo Susumu , Amano Toshimasa , Nagai Haruo
Published: November 2005

High-purity InP layers are grown using an LPE technique with Co addition. In an In–P solution, Co combines with P to form a CoP precipitate. Solution impurities were removed by incorporation into the CoP precipitate and the In–P solution was purified as a result. High-purity InP layers with 100,000–110,000 cm2/Vs of Hall mobility at 77 K were obtained by a combination of adding the Co and baking the In–P solution in wet hydrogen.
Diagnostics of Gas Reaction Using Trimethylgallium-AsH3 and Triethylgallium-AsH3 in Low-Pressure Organometallic Vapor Phase Epitaxy
Authors: Horiguchi Seishi , Kimura Kōzō , Takagishi Shigenori , Kamon Koichi , Mashita Masao , Mihara Minoru , Ishii Makoto
Published: November 2005

The dominant gas species produced in low-pressure organometallic vapor phase epitaxy (OMVPE) using trimethylgallium (TMG)-arsine (AsH3) and triethylgallium (TEG)-AsH3 systems have been studied with a quadrupole mass spectrometer. The gas species markedly depended on the growth pressure, which varied from 0.05 to 100 Torr. At pressures below 1 Torr, alkylarsines increased markedly with decreasing pressure. The dominant hydrocarbon species were CH4 in the TMG-AsH3 system and C2H4, C2H6 and C3H8 in the TEG-AsH3 system. In the TMG-AsH3 system, the CH4 concentration decreased with decreasing pressure below 1 Torr. In the TEG-AsH3 system, however, the species of the dominant hydrocarbons changed with pressure. A detailed analysis shows that CH3 radicals increase below 1 Torr, in good agreement with the increased carbon incorporation in OMVPE GaAs layers grown below 1 Torr.
In Doping in CdTe Film by Co-Evaporation of CdTe and In
Authors: Suzuki Tatsuro , Ema Yoshinori , Hayashi Toshiya
Published: November 2005

High-dark-conductivity CdTe films have been prepared by co-evaporation of CdTe and In. The conductivity of the films prepared in this study ranged from 10-8 to 103 Scm-1. The film structure was of the zinc-blende type with a preferential orientation of the (111) planes parallel to the substrate. Analyzing the film structure by X-ray analysis, it was found that the In atoms were doped substitutionally into the CdTe during the low-concentration doping stage and then doped interstitially during the high-concentration doping stage. The properties of a very-high-conductivity film could be explained by adopting a new periodicity concept of the doped film using a tentative model.
High-Mobility Two-Dimensional Electron Gas from Delta-Doped Asymmetric AlxGa1-xAs/GaAs/AlyGa1-yAs Quantum Wells
Authors: Horikoshi Yoshiji , Fischer Albrecht , Schubert Erdman F. , Ploog Klaus
Published: November 2005

A new delta (δ)-doped asymmetric Al
x
Ga1-x
As/GaAs/Al
y
Ga1-y
As quantum well structure is designed and grown by molecular beam epitaxy which provides a high-mobility two-dimensional electron gas with µ = 3.2×105 cm2/Vs at 5 K. The key feature of the new structure is that no bound states for electrons are found in the asymmetric well if the width is smaller than the critical value. The undesired persistent photoconductivity effect due to deep donors in n-type Al
x
Ga1-x
As: Si does not exist in the structure. Important for high transconductances in field-effect transistor is the narrow spacing between the two-dimensional electron gas and the crystal surface.
Minimum Voltages of Low Pressure r.f. Discharges in Static Magnetic Fields
Authors: Hayashi Yoji , Takeda Susumu
Published: November 2005

The minimum starting voltages of a r.f. discherge were experimentally and theoretically studied in low-pressure gases with static magnetic fields perpendicular to the electric field. The experiments were carryed out in argon and hydrogen with a frequency of 96 MHz, magnetic fields up to 400 gauss and at pressures of 10-4–10-2Torr. The minimum voltage which appeared at the higher magnetic field rather than that under the electron cyclotron resonance condition was theoretically analyzed by the balance equation of electrons and their trap codition in a gas. This confirms that the observed results are gaseous discharges even in such low pressures.
Superlattice Structure a-Si Films Fabricated by the Photo-CVD Method and their Application to Solar Cells
Authors: Tsuda Shinya , Tarui Hisaki , Matsuyama Takao , Takahama Tsuyoshi , Nakayama Shoichirou , Hishikawa Yoshihiro , Nakamura Noboru , Fukatsu Takeo , Ohnishi Michitoshi , Nakano Shoichi , Kawano Yukinori
Published: November 2005

Amorphous silicon superlattice structure films were fabricated by the photo-CVD method for the first time; also, the structural, optical and electrical properties of the films were investigated. A comparison of the photoluminescence intensities indicated that low damage to the interface was accomplished by using the photo-CVD method. A new type of solar cell was also developed using a superlattice structure as the p-layer of an a-Si solar cell. A conversion efficiency of 10.5% was obtained for a glass/TCO/p-superlattice structure/in/Metal a-Si solar cell.
Calculation of Projectile Velocity in an Electromagnetic Mass Driver
Authors: Ikuta Kazunari
Published: November 2005

The formula for the velocity increase of a projectile accelerated by a single z-pinch between cyclindrical electrodes has been established. This formula enables one to consider the necessary stages in a cylindrical electrode array of an accelerator for the required velocity.
Novel Methods for Measuring Diameter of Focused Ion Beam
Authors: Morita Tetsuo , Arimoto Hiroshi , Miyauchi Eizo , Hashimoto Hisao
Published: November 2005

Two methods are proposed for directly measuring the diameter of a focused ion beam from the secondary electron intensity profile obtained by scanning the beam across either a cleaved edge of or an alignment mark on a GaAs substrate. The calculation of the secondary electron intensity profile is based on the Monte Carlo simulation of the implanted ion trajectories. The experimental results agreed well with the calculated ones. Using these methods, beam diameters can easily be measured without special tools.
Characterization of a Newly Developed Contrast Enhancement Material for G-line Exposure
Authors: Nakase Makoto , Niki Hirokazu , Satoh Takashi , Kumagae Akitoshi
Published: November 2005

The bleaching characteristics for a contrast enhancement layer (CEL) material were succesfully described by parameters A, B and C; these were used for the modeling of a positive photoresist exposure. As a result, it was clarified that both the A and C values should be large, but the B value must be as small as possible. According to the obtained information, a new CEL material was proposed, which consists of the diazonium compound and the alkyl modified phenol resin. Using the composed CEL material, a submicron resist pattern with a steep profile was obtained. Furthermore, it was found that the development latitude increases, but that the exposure latitude does not change upon using the CEL.
Preparation of B–Si–Ge Alloys by Sputter-Assisted-Plasma CVD
Authors: Kohno Kenji , Imura Takeshi , Osaka Yukio
Published: November 2005

Microcrystalline and amorphous films of B–Si–Ge alloy have been deposited by the sputtering of a Ge target in atmospheres of SiH4 and B2H6. A microcrystal is mainly composed of Si and Ge in spite of large amounts of boron included in the film (up to 50 at.%). Probably most of the boron is located in the grain boundary. A lattice vibration mode due to a B–B configuration was observed as a sharp Raman scattering line at 1121 ± 1 cm-1.
ICTS Measurements of Interface Properties in GaSb MOS Structure
Authors: Nakashima Kenshiro
Published: November 2005

Interface state density distributions and hole capture cross sections have been determined as a function of the energy for MOS structures made with anodic oxides on p-type GaSb by the ICTS (isothermal capacitance transient spectroscopy) technique. The interface state density increases towards the band edge from 3×1011 to 1×1012/cm2eV in the energy range of 0.3 to 0.03 eV above the valence band.
Electrodeless Method for Measuring Photoconductivity Spectrum of Heat Treated Silicon
Authors: Nakashima Kenshiro
Published: November 2005

An electrodeless method for measuring photoconductivity spectra using microwave (10 GHz) absorption has been applied to high-resistivity silicon heat-treated at high temperatures. Experimental results show that this method is useful for measuring the photoionization energies for several kinds of defects, especially in high-resistivity materials.
Influence of Reactive Gas Pressure on the Properties of Thin Film Ta2O5
Authors: Teravaninthorn Utis , Miyahara Yuji , Moriizumi Toyosaka
Published: November 2005

An intensive investigation concerning the specific properties of DC reactively sputtered thin film Ta2O5 and the influence of the fabrication condition were carried out. The examined properties involved the electronic properties (dielectric constant, dielectric loss, leakage current and breakdown voltage), the optical property (refractive index) and the structural properties (crystalline structure and surface texture). Both the electronic and optical properties were found to depend on the gas pressure in the discharge chamber in which the film were grown; meanwhile the gas pressure caused no effects on the crystalline and surface texture of the film. The films which were formed under a lower sputtering gas pressure tended to occupy a higher dielectric constant and refractive index, and to occupy a lower dielectric loss and leakage current. In the electron diffraction analysis the deposited film showed an inherently amorphous crystalline structure. Thermal stability studies have shown that the annealing of Ta2O5 films could transform their amorphous structure to a polycrystalline type without perturbing the film surface texture. The critical temperature for such a transformation appears at 700°C.
Studies of Photon Energy Dependence of Transient Photocurrent in Semi-Insulating GaAs Materials by means of Photo-Deep-Level Fourier Spectroseopy and Photosensitivity Transient Spectroscopy
Authors: Ikeda Kousuke , Ishii Yoshikazu
Published: November 2005

The photon energy dependence of the transient photocurrent in Cr-doped semi-insulating GaAs materials was investigated by photo-deep-level Fourier spectroscopy (photo-DLFS) and photosensitivity transient spectroscopy (PSTS). From the experimental results, it was found that photo-DLFS signals change systematically according to the change in the photon energy of monochromatic light; fourteen deep levels were detected. It is shown that measurements taken while continuously varying the photon energy are very useful in studying specified deep levels in cases where the signals of two or more deep levels overlap and in detecting the many deep levels by increasing the change in the occupancy probability at each deep level. Also, a photoquenching effect is shown to occur within the new photon energy range, 0.85–0.92 eV, by PSTS.
“Effective” Magnetic Flux of NbN Nanobridges in a dc-SQUID
Authors: Yamashita Tsutomu , Hosokawa Katsuhiro
Published: November 2005

An investigation was carried out to discover whether the “effective” magnetic flux Φeff (=“effective” inductance times dc supercurrent) of a Josephson junction is detectable or not. In the experiment, the internal flux of a dc-SQUID with NbN nanobridges was measured using a SQUID fluxmeter. It was found that the internal flux of a dc-SQUID is strongly affected by the “effective” flux of Josephson junctions.
Molecular Beam Epitaxial Growth of GaAs Using Triethylgallium and As4
Authors: Kimura Kozo , Horiguchi Seishi , Kamon Koichi , Mashita Masao , Mihara Minoru , Ishii Makoto
Published: November 2005

The growth of undoped GaAs layers using molecular beams of triethylgallium (TEG) and elemental arsenic (As4) was studied. All epilayers showed a p-type conductivity caused by carbon as the main residual acceptor. The carrier concentration decreased as the As4-to-TEG pressure ratio was increased, resulting in the lowest value of p=3×1014 cm-3 at an As4-to-TEG pressure ratio of 67. A mass spectrometric analysis during growth revealed the formation of ethylarsine compounds.
Ion Cyclotron Drift Waves in Plasmas with Controlled Radial Density Distributions
Authors: Kando Masashi , Ikezawa Shunjiro , Sugai Hideo , Kishimoto Shigeru
Published: November 2005

The ion cyclotron drift wave (ICDW), which is the mode coupled between the electrostatic ion cyclotron wave and the drift wave, was investigated by experiments and calculations. The calculated dispersion relations for the m=1 mode show that the mode coupling becomes stronger with increasing |κ| (where κ=dn/dr/n) and a resonance aroud the ion cyclotron frequency changes to a cutoff when |κ| exceeds the azimuthal wave number k
y. A simple method to control the radial density distribution is proposed and is confirmed to be varied to a considerable extent. Ion cyclotron drift waves for the m=1, m=-1 and m=2 modes have been excited externally with controlled values of |κ|. The measured dispersion relations agree with the theoretical predictions.
Quasistatic 2-D MHD Equilibrium Calculations for Oscillating-Current RFP Plasmas
Authors: Asaina Tsutomu , Yoshida Zensho , Murakami Yoshiki , Inoue Nobuyuki
Published: November 2005

Quasistatic 2-D MHD equilibrium has been studied, by solving the Grad-Shafranov equation coupled with circuit equations for coil and shell currents, for RFP plasmas with F-Θ pumping current-drive electric fields. The effect of a resistive shell has been taken into account, as well as the image field from an iron core. The shift of the magnetic axis has been evaluated for the dimensions of the REPUTE-1 RFP device.
Performance Test of the TOPAZ Barrel Calorimeter
Authors: Kuroda Shigeru , Kawabata Setsuya , Sugahara Ryuhei , Tauchi Toshiaki , Ujiie Norihiko , Watanabe Yasushi , Suwada Tsuyoshi
Published: November 2005

A large-scale electromagnetic calorimeter comprising 4300 lead glass Cherenkov counters has been constructed for the TOPAZ detector at the TRISTAN e
+
e
- collider. Various beam tests have been performed to study the basic properties. The data were compared with simulated data based on the EGS4 code. In this report, the results of beam tests and a comparison to simulated data are described.
Production of Fast Neutral Lithium Beam for High Temperature Plasma Probing
Authors: Yamaoka Hitoshi , Kadota Kiyoshi , Okuno Kazuhiko , Masamune Sadao , Miyake Shoji , Fujita Junji
Published: November 2005

A high-current lithium ion beam of a few mAcm-2 with an energy of 12 keV and a minimum beam divergence of about 1.2° has been produced by using an ion source of the discharge type. Characteristics of the lithium ion beam regarding the intensity and divergence were experimentally investigated in detail. A lithium neutral beam has been produced using a sodium neutralizer. The neutralization efficiency of the lithium ion beam in the energy range of 2–15 keV was about 80% with a neutralizer at a vapor pressure of 1.7×10-3 Torr. A mass analysis was performed when a mixed discharge of lithium and argon was used. The ratio of R (argon-ion current/lithium-ion current) became less than 0.1 at the oven temperature of the ion source to about 700°C. The applicability of a fast neutral lithium beam to plasma probing is discussed.
Ion-Implantation Induced Damage in AlxGa1-xAs and Superlattices Studied by Rutherford Backscattering
Authors: Matsui Kazunori , Takamori Takeshi , Fukunaga Toshiaki , Narusawa Tadashi , Nakashima Hisao
Published: November 2005

Rutherford backscattering of 2-MeV He+ with channeling was used to study damage distributions in Al
x
Ga1-x
As and GaAs/Al
x
Ga1-x
As superlattices induced by Si implantation. Various samples were prepared with different implantation doses and energies, AlAs composition x, periodicity of superlattices, and annealing temperature. We obtained the following results: (1) the amount of damage in AlGaAs is about one tenth of that in GaAs or AlAs, (2) GaAs layers are preferentially damaged in superlattice structures independent of the Al composition in Al
x
Ga1-x
As and (3) implantation-induced damage disappears almost completely after annealing at 800°C for 15 min.
A New X-Ray Lithographic Technique Using Total Reflection of X-Rays from a Pattern Plate
Authors: Matsumura Hideki , Tanaka Takeshi
Published: November 2005

A new X-ray lithographic technique which uses no thin film pattern masks is presented. In this new technique, the patterns are projected by the reflection of X-rays from a hard, thick pattern plate instead of transmission through a feeble, thin pattern mask; also, the patterns are demagnified. The feasibility of demagnified projection printing to a sub-micron scale by this technique has been shown by preliminary experiments; it has also been estimated from a theoretical study that 1/ 10 demagnified printing with a field area of 1 mm width is possible for a pattern-blur of less than 0.06 µm.
Internal Loss and Gain Factor of InGaAsP/GaAs Laser
Authors: Ito Toshio , Ishikawa Joji , Sube Makoto , Takahashi N. Shin-ichi , Kurita Shoichi
Published: November 2005

The internal loss α and gain factor β of InGaAsP/GaAs double-heterostructure lasers were examined by immersing laser chips into various liquids and changing the reflectivities of a Fabry-Perot mirror. Only a small scatter was found; we evaluated α and β as 20.6 cm-1 and 0.0129 cm·A-1, respectively. The value of α was compared with the loss of AlGaAs/GaAs lasers.
Strained N–Ga0.7Al0.3As/InxGa1-xAs/GaAs Modulation-Doped Structures
Authors: Okamoto Akihiko , Toyoshima Hideo , Ohata Keiichi
Published: November 2005

Strained N–Ga0.7Al0.3As/In
x
Ga1-x
As/GaAs modulation-doped structures were successfully fabricated. Also, a high concentration of two-dimensional electron gas (2DEG) (about 2×1012cm-2) was found to accumulate at heterointerfaces. Upon increasing the In composition in the InGaAs layer, the 2DEG concentration increased and the mobility decreased. Thus, a modulation-doped structure with In0.23Ga0.77As at room temperature has the lowest sheet resistance (about 500 ohms); this is two thirds of that for a conventional modulation-doped structure. The proposed structure is promising for field effect transistors with low channel resistances.
Suppression of Electron-Hole Droplet Transport by Deep Impurities in Germanium
Authors: Ogawa Kensuke , Ohyama Tyuzi , Otsuka Eizo
Published: November 2005

Transport of an electron-hole droplet and the creation of a strain-confined electron-hole liquid in strained Ge doped with a deep impurity Zn were investigated by means of spatial resolution measurements of the recombination luminescence from normal e-h drops as well as a strain-confined large e-h drops under cw-Ar+-laser excitation. A simple drift model is proposed. The drift mobility of an e-h pair composing the droplet decreases from (8.7±0.3)×105 cm2/Vs in pure Ge to (4.5±0.2)×105 cm2/Vs in Zn-doped Ge at 1.8 K. Spatial distribution profiles of free and bound excitons coexisting with e-h drops at 4.2 K are also presented.
Dye-Sensitized Cuprrous Iodide Photocathode
Authors: Tennakone K. , Fernando C. A. N. , Dewasurendra M. , Kariappert M. S.
Published: November 2005

Copper plates coated with cuprous iodide (p-type semiconductor) are found to adsorb iodides of cationic dyes extremely well. Photocurrent efficiency and stability of dye-sensitized CuI photocathodes in aqueous KI+I2 are studied. Deposition of trace quantities of platinum on top of the dye layer is found to increase the stability and the photocurrent quantum efficiency.
Peak Velocity in Orthorhombic Bubble Films
Authors: Speidel Stefan , Iwata Satoshi , Uchiyama Susumu
Published: November 2005

The dynamics of domain walls in bubble films with orthorhombic anisotropy, which are known for their very high peak velocities, are examined in detail by solving the equations of motion numerically. The dependence of the peak velocity on the orientation of the domain wall with respect to the in-plane easy axis is discussed with the strength of the in-plane anisotropy as a parameter. For weakly twisted walls both parallel and perpendicular to the in-plane easy axis, an approximate expression for the nucleation threshold and the corresponding critical velocity is derived. This velocity is found to be a close approximation of the numerical results and to lie considerably below the maximum velocity of the one-dimensional theory over a large part of the range of anisotropy values examined experimentally. Measurements of the peak velocity are performed on the shrinking velocity of stripe heads. Velocities are found to increase strongly with increasing in-plane anisotropy as expected from the theoretical results, but to be generally about 10% too low.
Deep Levels in Argon-Implanted and Annealed Indium Phosphide
Authors: Luo Ji-Kui , Kimura Tadamasa , Yugo Shigemi , Adachi Yoshio
Published: November 2005

Deep levels in InP caused by Ar-ion implantation and their annealing behaviours by rapid halogen lamp (RHL) annealing in the temperature range from 740 to 935°C were invesitigated using deep level transient spectroscopy (DLTS) and photoluminescence (PL). The DLTS measurements showed that the RHL annealing, alone, induced electron trap levels E2(0.52 eV) at low temperatures and E1(0.65 eV) at high temperatures. The Ar-ion implantation increased the E2 trap density by two orders of magnitude and caused new traps: E3(0.37 eV), E4(0.25 eV), E5(0.19 eV) and E6(0.17 eV). Subsequent RHL annealing decreased the E3–E6 traps below the detection limit (above 880°C) and E2 to the same level as that of unimplanted/annealed InP at 920°C. Results of the PL measurements are also presented and discussed in relation to the DLTS measurements.
Reverse Current Characteristics of Hydrogenated Amorphous Silicon-Crystalline Silicon Heterojunctions
Authors: Mimura Hidenori , Hatanaka Yoshinori
Published: November 2005

The electrical properties of heterojunctions of p-type a-Si:H and n-type c-Si have been investigated by measuring I–V and C–V characteristics. The C–V characteristics revealed that there was something (what is called interface defect states) to obstruct the spread of the depletion layer in c-Si at the interface of a-Si:H and c-Si. The I–V characteristics showed that these interface defect states assisted the generation of a reverse current. The calculation suggested that only the interface defect states near the midgap influenced the reverse current. Consequently, to realize a low dark current applicable to imaging devices, it was necessary to decrease the number of interface defect states.
The Design and Performance of Multiwire Proportional Chambers for High Flux Beam Monitoring
Authors: Homma Takahide , Daigo Motomasa , Haba Junji , Kawai Hideyuki , Kobayashi Makoto , Miyake Kozo , Nakamura Takashi S. , Sasao Noboru , Sugimoto Yasuhiro
Published: November 2005

Multiwire proportional chambers with 1 mm-pitch anode wires and carbon-coated cathode planes were constructed and used to monitor a high-intensity beam. The chambers have been operated with more than 98% efficiency over one year long experiments and showed no deterioration after an injection of 1012 particles. The chamber system has been used to measure the momenta as well as the trajectories of incident particles on an event-by-event basis. A typical momentum resolution (FWHM) of 0.5% was achieved.
Portable and High-Sensitive Apparatus for Measurement of Environmental Radon Using CR-39 Track Detector
Authors: Miyake Hiroshi , Oda Keiji , Michijima Masami
Published: November 2005

Highly sensitive, electrostatic collection chambers have been developed for low-level radon measurements using CR-39 plastic track detectors. Chambers with outer electrodes shaped as a cone and a hemisphere with lines of electric force that were focused on the center of the collector electrode gave alpha-track distributions similar to a 2-dimensional Gaussian with a FWHM of less than 3 mm. The sensitivities, defined as the track density for a radon exposure of 1 Bq h/m3, were more than 4 tracks/cm2 using a chamber with a volume of about 300 cm3. The dependencies of the sensitivity and the track distribution on the collector voltage and humidity were investigated.
Thermal Characteristics of a Metal-Film Bolometer
Authors: Ogawa Isamu , Noda Nobuaki , Kawahata Kazuo , Ogawa Yuichi , Fujita Junji
Published: November 2005

A metal-film bolometer has been developed for reliable measurements of the radiation power from high-temperature plasmas. Its sensitivity and time response were improved by reducing the absorber thickness (10 µm) to the minimum limit in order to sufficiently absorb photons with high energies up to 3 keV. In addition, this detector has well-defined thermal characteristics. The deviation of the measured value arising from thermal cooling was investigated by numerically solving a heat conduction equation associated with the detector. The calculated results could explain the thermal characteristics well for a temporally constant power (at calibration) and showed that the deviation of the measured radiation power from its calculated value could be reduced by a precise correction (to the extent of 0.5%).
Spatial Distributions of Damage Introduced into GaP by Collimated MeV-Electron Beams–Lateral Spreads of Damage Compared with Electron Spreads
Authors: Endo Tamio , Nakakuki Kiyoshi , Kuno Katsumi , Sugiyama Koichi
Published: November 2005

Two-dimensional density distributions of damage, introduced into GaP by irradiation of the electron beams collimated by a slit with a 0.5 mm gap at incident energies of 10 and 16 MeV, were obtained by using optical density measurements. The lateral profile of damage can be approximated by a Gaussian profile for a depth z>2 mm; its lateral spread Δp increases from 0.29 to 2.35 mm for z=0.01 to 6.1 mm for 10 MeV. The increase in Δp is larger for a 10 MeV-electron beam than for a 16 MeV beam. This is explained by the larger lateral spread of traversing electrons for 10 MeV. The damage does not spread laterally as much as the electrons, which leads to a decrease of the lateral damage introduction rate. This is discussed in terms of the energy distribution and the scattering angle of electrons in matter.
Dislocation Reactions in a Boundary of a White Tin Crystal
Authors: Honda Katuhiko
Published: November 2005

On the basis of new observations using the etch hillick technique, one conclusion concerning dislocation reactions reported in a previous short note is partly corrected. The reactions represent a coalescence of two dislocations and the splitting of a single dislocation into two dislocation. They are expressed by (1/2)[111](1̄10)+(1/2)[11̄1̄](110)\rightleftharpoons[100](010).
Very Faint Light Emission in Low-Density Polyethylene Films under dc Field
Authors: Kitani Isamu , Hirano Tomohisa , Arii Kiyomitsu
Published: November 2005

Faint light emission in low-density polyethylene films was detected by using a photon-counting system. The photoncount response rose to a maximum value at a time greater than 1 minute after a step voltage was applied. The emission spectra ranged between 300 and 540 nm. The light-emission process was attributed to a recombination between trapped electrons and trapped holes.
Isotope Effect in the O2 and SO Molecules
Authors: Mizushima Masataka
Published: November 2005

The rotational energy, spin-orbit coupling, spin-spin coupling, and the coupling between the molecular rotation and the electron spin are taken into account up to the second order perturbation in the Born-Oppenheimer approximation. The resulting expressions of coupling constants, such as B
e, D
e, α, αD, λe, λD, λDD, αλ, αλD, αλDD, γe, γD, αγ, αλD, in the effective Hamiltonian show specific dependences on the reduced mass µ of the diatomic molecule under consideration. The theory is tested for 13 molecular parameters for the O2 isotope molecules and 8 molecular parameters for the SO isotope molecules and they all agree with experimental data within the presently available accuracy.
Component Assignments of the Raman Spectrum from Highly Elongated Silica Glass Filbers
Authors: Ema Kazuhiro , Hibino Yoshinori , Shigekawa Hidemi , Hyodo Shin-ichi
Published: November 2005

Raman spectra from glass fibers subjected to high tensile stresses (up to 4 GPa) were decomposed into their Gaussian components, which were then assigned to normal vibrational modes of either SiO4 or Si2O molecules using an “isolated molecule" model. Such molecule-related parameters as force constants, Raman coupling constants and the dispersion of the intertetrahedral bond angle were estimated from the frequencies, heights and widths of the components. It is concluded from the analysis that the Raman spectrum change associated with the application of tensile stress arises principally, not from a Si–O bond stretching or Si–O–Si bond angle broadening, but from a change in the tetrahedral angles of the SiO4 molecules constituting silica glass networks.
Photoinduced Absorption on Phosphorus and Nitrogen Doped a-Si:H Films Prepared at High Deposition-Rate
Authors: Ueda Masato , Imura Takeshi , Osaka Yukio
Published: November 2005

Photoinduced absorption (PA) measurements were carried out for plaosphorus- and nitrogen-doped hydrogenated amorphous silicon films prepared at a high deposition rate. We introduced an “empirical" doping efficiency η* which was determined from the changes induced by doping on the activation energy of conductivity and on the threshold energy of a hole trapped center in PA measurements.
The η* has been found to be a meaningful quantity as a qualitative measure of the doping efficiency in phosphorusdoped films. On the basis of the changes in η* induced by doping, the doping effects in nitrogen-doped films are discussed.
Low Dielectric Constant Amorphous SiBN Ternary Films Prepared by Plasma-Enhanced Deposition
Authors: Maeda Masahiko , Makino TakaHiro
Published: November 2005

A novel insulation films named amorphous SiBN ternary films are investigated. These films have been prepared by plasma-enhanced chemical vapor deposition using SiH4–B2H6–NH3–Ar mixture. The dependences of film properties on film composition are systematically investigated. It is found that these films show good insulation characteristics and conformal step coverage. These films can be easily etched by reactive ion etching using H2/CF4 gas mixture. Very low dielectric constant lower than that of silicon dioxide is realized when the B atomic ratios are beyond 0.30. Boron nitride shows hygroscopic properties while stability to moisture is confirmed for SiBN films. Therefore SiBN films will be applicable as inter-layer insulation in a low parastic capacitance multi-level metallization.
1H Nuclear Magnetic Resonance Study of Hydrated Surface of Ultra-Fine Powder of Aluminum Nitride
Authors: Hayashi Shigenobu , Hayamizu Kikuko , Yamamoto Osamu
Published: November 2005

The motional properties and thermal stabilities of proton-containing species adsorbed on an ultra-fine powder of aluminum nitride were studied by means of 1H NMR and are here discussed along with a structural model.