bluuebunny/crossref_metadata_2025 huggingface dataset:
Picosecond Pulse Sources by Čerenkov Light Generated from Fused Silica and Water
Authors: Wakita Shohei , Washio Masakazu , Suzuki Yoshiro , Hirai Masamitsu
Published: November 2005

Characteristics of the picosecond Čerenkov light pulse generated from fused silica in a shape of cone and from water in a conical vessel have been investigated in the wavelength range from 230 nm to 500 nm. The pulse durations are estimated to be 27.0±4.0 ps for fused silica and 30.0±7.0 ps for water. It is shown that the present Čerenkov light pulse can be used for measuring the luminescent decay time in the picosecond range in conventional materials such as PPO and Tl+ monomers in KI crystals at room temperature.
Magnetic Properties of W-Type Hexaferrite Powders
Authors: Kojima Hiroshi , Miyakawa Choji , Sato Takafumi , Goto Kimiyoshi
Published: November 2005

An investigation was undertaken to elucidate the preparation conditions and magnetic properties of W-type hexaferrite powders with the formula AM2Fe16O27 (A=Ba or Sr, M=Fe2+, Zn+Cu, Zn+Cd, Zn+Mg). A pure W-phase was formed by firing a mixture of carbonates and oxides in the appropriate molar ratio at 1200^° ∼1400^°C in an atmosphere of P
O2
/(P
O2
+P
N2
)=10-2 ∼10-6 or in air. The values σs=70 ∼79 emu/g, H
c=400 ∼2000 Oe, σr/σs ∼0.90 and T
c=350^° ∼500^°C were obtained for the oxide powders, aligned along the c axis.
LPE Growth of In1-xGaxP0.96As0.04 on GaAs Substrate by Two-Phase Melt Method.
Authors: Shirakata Sho , Kondo Masahiko , Tsushi Akihito , Nishino Taneo , Hamakawa Yoshihiro , Kariya Tetsuya
Published: November 2005

In1-x
Ga
x
P0.96As0.04 LPE layers were grown on (100) GaAs substrates from a two-phase solution with an excess GaP source at 785°C and 795°C. The relations between the liquid compositions of Ga and P, X
Ga
l and X
P
l, at 800°C, were obtained experimentally for a liquid composition of As, X
As
l, of 0.76 at%. Based on these results, it was found that high-quality InGaPAs LPE-layers can be grown from an In melt with X
Ga
l between 1.10 at% and 1.30 at% and X
P
l between 2.85 at% and 2.90 at%. The liquid and solid compositions are discussed in connection with the calculated In-Ga-P-As phase diagram. The characteristics of the solution were examined by changing the growth time and temperature, and the crystal quality of the InGaPAs LPE layers was examined by a photoluminescence method in terms of the lattice mismatch between the InGaPAs LPE layer and the GaAs substrate
Fluorescence-Detected X-Ray Absorption Spectroscopy Applied to Structural Characterization of Very Thin Films; Ion-Beam-Induced Modification of Thin Ni Layers on Si(100)
Authors: Oyanagi Hiroyuki , Matsushita Tadashi , Tanoue Hisao , Ishiguro Takehiko , Kohra Kazutake
Published: November 2005

The design features and performance of a newly-developed multi-detector system for fluorescence-detected X-ray absorption spectroscopy (XAS) using synchrotron radiation are presented, and the feasibility of fluorescence-detected XAS for structural studies of very thin films is discussed. It is demonstrated that this technique can be a powerful structural characterization tool for thin films with a wide range of thickness from a few thousand Å down to some tens of Å. The possibility of a monolayer experiment with further improvements to the present system is suggested from experiments on films with a Ni coverage of 3.2×1016/cm2. The structural modification of thin nickel films deposited on Si(100) induced by ion-beam bombardment was investigated, and the formation of amorphous Si-rich nickel silicide as a result of argon ion bombardment at a low substrate temperature is reported.
Annealing Behavior of Arsenic and Gallium Implanted in Silicon with Thin Native-Oxide Films
Authors: Yokota Katsuhiro , Tamura Susumu , Ishihara Shinji , Kimura Itsuro
Published: November 2005

The influence of thin native oxide films (∼25 Å) on the annealing behavior of As and Ga implanted in Si has been studied. Although no implanted As evaporated from the solids into the ambient atmosphere during annealing, the amount of implanted As diffusing from the Si into the native-oxide films increased with the annealing temperature to 2×1014 cm-2 at a dose of 1×1016 cm-2 at an annealing temperature of 1100°C. On the other hand, the amount of implanted Ga evaporating from the solids into the ambient atmosphere increased exponentially with the annealing temperature; the amount of implanted Ga remaining in the Si was only 7% of the dose of 1×1015 cm-2 at an annealing temperature of 1100°C.
Far-Infrared Optical Properties of Quenched Germanium. II. Magnetic Field Effects
Authors: Hattori Takeshi , Kurata Tetsuyuki , Fujii Eiji , Mitsuishi Akiyoshi , Kamiura Yoichi
Published: November 2005

The far-infrared absorption spectra of quenched germanium were measured with the magnetic field parallel to the <001 > and <111 > crystallographic orientations. The ground states of both SA1 and SA2 acceptors, which are observed among the quenched-in acceptors, are split into two levels corresponding to states with quantum numbers of ±1/2 and ±3/2. It is concluded that D and C bands, the absorption bands for the acceptors, are due to transitions from the \varGamma8
+ ground state to the \varGamma8
- and \varGamma7
- excited states, respectively. The quantum numbers of the Zeeman splitting states concerning the transitions of the D and C bands and the g-factors of these excited states for SA1 and SA2 acceptors were determined. The Zeeman splitting of the ground state is negligible compared with those of the excited states.
Construction of a Tunable Waveguide CO2 Laser and Its Operating Characteristics
Authors: Ito Nobuhiko , Ciddor Philip E.
Published: November 2005

This paper describes a simplified waveguide CO2 laser which can be used in length and distance measurement as a local oscillator when used in conjunction with a heterodyne technique.
The dependence of the tunability and output power on the pressure and discharge current were investigated and compared with the phenomenological theory of Degnan. [J. J. Degnan: J. Appl. Phys. 45 (1975) 257].
The use of this laser, which has tube and cavity lengths of 280 mm and 620 mm, respectively, gives an output power and tunability of up to 0.8 W and over 300 MHz, respectively, on the 10P(20) transition line, with good wavelength selectivity in the 10 µm band and also with good discrmination of the EH11 mode from other transverse modes.
Fundamental Studies on One-Dimensional Cannonball Targets at 10.6 µm Laser Wavelength
Authors: Fujita Masayuki , Daido Hiroyuki , Nishimura Hiroaki , Tateyama Ryuji , Ogura Kazuki , Miki Futoshi , Terai Kiyohisa , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

A new scheme for the inertial confinment fusion (ICF) pellet, called a Cannonball target, has been investigated experimentally using a 10.6 µm laser. The fuel pellet is surrounded by a tamper with a vacuum between the two, and the laser energy is introduced into this space through a small hole in the tamper. The fundamental properties of the Cannon-ball target, such as its absorption and hydrodynamics, and the emission spectra of ions and electrons, have been investigated. The results show a good absorption of 50% and a high hydrodynamic efficiency of 16%. It was found possible to suppress hot-electron preheating.
ESR Study of X-Irradiated Ba(NO3)2
Authors: Tagaya Kimihito
Published: November 2005

Single crystals of Ba(NO3)2 were irradiated with X-rays at room temperature, and ESR measurements were performed over the temperature range from 85 K to 373 K. It was concluded that F, O2
-, O3
- and NO2 centers were produced. The sites and orientations of O2
- and NO2 centers in a Ba(NO3)2 crystal were determined from the principal directions of the g or hyperfine tensor. The superhyperfine interactions of F and O2
- centers with adjacent 135Ba, 137Ba and 14N nuclei were investigated. Optical absorption measurements were also performed, and it was concluded that the absorption band at 335 mµ was due to the F-center.
Coloration and Decoloration in Atmospheric-Evaporated Tungsten-Oxide Films (AETOF) Utilizing Lithium Ions
Authors: Morita Hiroshi
Published: November 2005

The electrochemical coloration and decoloration processes in atmospheric-evaporated tungsten-oxide films (AETOF) utilizing a lithium electrolyte were investigated.
Because of the comparatively large diffusion coefficients for lithium in AETOF (2 ∼3 ×10-9 cm2/s), conventional models proposed for tungsten oxide with a proton electrolyte were also found to be applicable to AETOF with a lithium electrolyte.
A New Method for Measuring Optical Activity in Crystals and Its Application to Quartz
Authors: Horinaka Hiromichi , Tomii Kazushi , Sonomura Hajimu , Miyauchi Takeshi
Published: November 2005

This report describes a theoretical study of a convenient method for measuring the optical activity in crystals in which birefringence and optical activity coexist. The method was applied to right-handed quartz. The gyrations in the [100] direction and at 45° from the optical axis were measured. The gyration tensor component g
33 calculated from the gyrations measured in these two directions was found to be in good agreement with the value of g
33 measured by other workers in the direction of the c-axis (the optical axis) by conventional methods.
Ion-Beam Modification of Amorphous WO3 Film and Its Properties as a High-Contrast Inorganic Ion Resist
Authors: Koshida Nobuyoshi , Tomita Osamu
Published: November 2005

The effect of ion-beam irradiation on amorphous WO3 films was studied experimentally and in detail using thermionic Na+ ions with an accelerating voltage of 4∼12 kV. The films exhibit a resistive property of extremely high contrast (γ≃8) at ion doses beyond a threshold value D
th. The sensitivity (D
th ≃5 ×10-4 C/cm2 at 5 kV), which is almost independent of the film thickness, decreases gradually with increasing accelerating voltage. The behavior of the optical absorption spectra and the ion-induced secondary electron emission yield of the irradiated films suggests the formation of sodium tungsten bronze, Na
x
WO3, by ion implantation. The resistive property can thus be explained from the metal transition of Na
x
WO3 at the threshold dose.
A New Planarization Technique for LSI Fabrication Utilizing Si-Ge Film Oxidation
Authors: Ogino Toshio , Amemiya Yoshihito
Published: November 2005

A new planarization technique in the LSI process utilizing Si-Ge film oxidation is proposed. The Si-Ge film is deposited by the thermal decomposition of SiH4 and GeH4 and then oxidized in wet O2 ambient. During the oxidation, a large degree of fluidity appears below 800°C, a temperature much lower than that needed for phosphosilicate glass flow. The oxide growth rate is more than one order of magnitude higher than that in crystalline Si. The oxide thickness decreases with increasing Ge content and oxidation temperature, owing to Ge evaporation. This planarization is related to Ge evaporation. After the entire Si-Ge film has been oxidized, neither glass flow nor Ge evaporation occur, even at temperatures higher than that of the oxidation. The electrical properties of the Si-Ge oxide film are good enough for its use as an insulating layer. The film does not react with an underlying SiO2 or Si3N4 layer.
Simultaneous Chemical Doping and Electrochemical Undoping in Conducting Polymer
Authors: Kaneto Keiichi , Shiraishi Taketora , Yoshino Katsumi
Published: November 2005

A new type cell utilizing spontaneous chemical doping and simultaneous electrochemical undoping in conducting polymers is studied. Open circuit voltage of 0.86 V and continuous short circuit current of ca. 2 mA are obtained in a cell consisting of polythiophene film (1.8 cm2×20 µm, 5 mg) as an electrocatalytic cathode against lead anode in sulfuric acid.
Jet Formation and Application for Inertial Confinement Fusion Target
Authors: Ozaki Tetsu , Higaki Satoshi , Fujita Hirokazu , Miyamoto Shuji , Imasaki Kazuo , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

A high velocity jet was formed by the Munroe-Neumann effect on a hemi-spherical target irradiated by a relativistic electron beam. The jet velocity and velocity multiplication were measured using N2 laser shadowgraphies and a charge collector array. A jet efficiency of about 50% was measured by a calory meter. These values agreed with theoretical predictions. Experimental results indicated that a reduction of the velocity requirement for pellet ignition may be possible.
Soft X-Ray Image Sensor Using Hydrogenated Amorphous Silicon
Authors: Hatanaka Yoshinori , Mimura Zeng
Published: November 2005

The effective absorption coefficient of a-Si:H was measured as 100 to 300 cm-1 for an X-ray tube voltage of 50 kV to 10 kV. For soft X-ray image sensor, a-Si:H target vidicons with a Be face plate were demonstrated. Resolution of a 1 inch tube was greater than 800 TV lines and sensitivity was 1.13 nA/cm2/mR for an a-Si:H film about 7 µm thick.
A 1.3 µm InGaAsP/InP Multiquantum Well Laser Grown by LPE
Authors: Sasai Yoichi , Hase Nobuyasu , Kajiwara Takao
Published: November 2005

We have successfully achieved a 1.3 µm InGaAsP/InP BH laser with multiquantum well active layers grown by low-temperature LPE technique (T

g
=589°C). The thickness of thin epitaxial layers was less than de Broglie wavelength. The laser has a threshold current of 19 mA, an external differential quantum efficiency of ∼40%, and T
0 value of ∼145 K in the range from -5°C to 20°C and ∼60 K from 20°C to 70°C.
On the Structure Match at Interfaces between α-Si:H Alloys
Authors: Wagner Sigurd
Published: November 2005

A criterion is proposed for the structure match at α-Si:H based interfaces. This criterion is the average interatomic radius  of alloys between Si and other network-forming elements. Alloys can be made to match with un-alloyed α-Si:H by the addition of pairs of alloying elements in appropriate concentration ratios.
Effect of Dislocations on Sheet Carrier Concentration of Si-Implanted, Semi-Insulating, Liquid-Encapsulated Czochralski Grown GaAs
Authors: Hyuga Fumiaki
Published: November 2005

The quantitative effect of dislocations on the sheet carrier concentration of a Si-implanted and annealed layer in semi-insulating GaAs is investigated microscopically by the van der Pauw method using small Hall chips with a 40×40 µm2 measurement area. Dislocations affect the sheet carrier concentration within about a 75 µm radius area, and the carrier concentration increases 3×1015 cm-3 per dislocation in this area.
Observation of a Long-Life Photoelectrochemical Conversion with n-Type Porous-Si Photoelectrodes
Authors: Koshida Nobuyoshi , Kiuchi Yuji
Published: November 2005

Application of an n-type porous-Si layer (PSL) as a working electrode of a photoelectrochemical cell was investigated. The introduction of the porous structure produced a drastic improvement in the life of n-Si under photoanodic operation. A linear relationship between the total output charge and the PSL thickness was found. At a PSL thickness of 20 µm, the photoanode remained alive until several C/cm2 charges were passed; this was three orders of magnitude more than was obtained from naked n-Si photoanodes. The H2 evolution rate from Pt counterelectrode was then about 100 µmol/10 h. The prolonged operation is closely related to an enhanced active area.
Thermal Stability of a Short Period AlAs/n-GaAs Superlattice
Authors: Iwata Naotaka , Matsumoto Yoshishige , Baba Toshio
Published: November 2005

Stability was examined for an AlAs/n-GaAs superlattice (SL), whose Si donors were confined to the GaAs layer. The SL was grown by MBE at 520°C and was annealed at a temperature (T
a) from 560 to 800°C. Up to T
a=600^°C, no sign of Al-Ga mixing was observed, and the amount of a DX centerlike trap was proportional to exp
(-0.65 eV/k
T
a). The increase in the trap was due to Si diffusion to the AlAs/GaAs interfaces with the activation energy of 1.3 eV for its diffusion coefficient. As increasing T
a above 650°C, Al-Ga mixing was accelerated and a decrease in carrier concentration and an increase in persistent photoconductivity were observed.
Three Color Switching Electrochromic Display Using Organic Redox-Pair Dyes
Authors: Ueno Toshihiko , Hirai Yoshihiko , Tani Chizuka
Published: November 2005

A new organic electrochromic display has been developed, which can display three different colors (red, green and greenish-blue) on a white background using new redox-pair dyes. The new dyes are composed of an anthraquinone compound showing red coloration at the reduced state, and a diphenylamine compound which shows green and greenish-blue colorations at two different oxidized states.
The Collision Behavior of Free Molecules in Combustion Fields
Authors: Ohsawa Toshihiko , Ozaki Tadao
Published: November 2005

The collision behavior of free molecules in flame is described. A fine particle generating system was adapted for observing the diffusion coefficient by means of dynamic light scattering. Electron microscopic examination of the generating particles shows them to reach a diameter of about 30 nm.
From the observed diffusion coefficient and particle radius, it appears that the mean free path in the flame is very short compared with thermodynamical estimation–about one fortieth as long.
The Effect of Cu Additive on A.C. Conductivity in a-As2Se3
Authors: Takano Yasushi , Kitao Michihiko , Yamada Shoji
Published: November 2005

A.c. conductivity of a-As40Se60Cu
x
(x=0 ∼2) has been investigated at various frequencies from 30 Hz to 300 kHz and at various temperatures from 77 to 350 K. A.c. conductivity of Cu-doped samples can be explained by assuming that both single-polaron hopping and bipolaron hopping are present. The effect of Cu additive on a.c. conductivity is compared with that of Ag additive.
Perpendicular Magnetic Anisotropy of Amorphous Fe-Nd Alloy Thin Films
Authors: Suzuki Takao
Published: November 2005

The dependence of perpendicular magnetic anisotropy on concentration and temperature in Fe100-x
Nd
x
thin films (18 ≤x ≤60) fabricated by rf sputtering is described. The perpendicular magnetic anisotropy constant K
u is maximum (\doteqdot1 ×107 erg/cc) for films with x=40 ∼45 made at substrate temperatures in the range from 220°C to 290°C. The presence of the maximum of K
u as a function of temperature is also found for x= 35 and 40 at 40 K and 80 K, respectively.
Two-Dimensional Electron Gas in an n+-GaAs/Undoped AlGaAs/Undoped GaAs SIS Structure
Authors: Wada Toshimi , Matsumoto Kazuhiko , Ogura Mutsuo , Shida Katsunori , Yao Takafumi , Igarashi Takashi , Hashizume Nobuo , Hayashi Yutaka
Published: November 2005

The two-dimensionality of the electronic system in a new self-aligned GaAs MIS-like FET having an n+-GaAs/undoped AlGaAs/undoped GaAs SIS structure is demonstrated by the angular dependent characteristics of SdH effects. The mobility of two-dimensional electron gas in a GaAs-SISFET is shown to be 120000 cm2/V·s with a sheet carrier concentration of 6.6×1011 cm-2 at 4.2 K and V
G=0.6 V. The quantized Hall effect is realized by changing gate voltages at as low a magnetic field as 3.5 T.
Advanced Techniques to Decrease Defect Density in Molecular Beam Epitaxial Silicon Films
Authors: Tatsumi Toru , Aizaki Naoaki , Tsuya Hideki
Published: November 2005

Defect density dependence on various surface cleaning conditions for molecular beam epitaxial (MBE) silicon films was investigated. Defect-free films were obtained on (100) and (511) wafers, using a combination of ozone cleaning and predeposition process after the usual wet cleaning. On the (111) wafer, the defect density dependence on growth rate was examined. The two-step growth-rate procedure was effective in decreasing stacking faults on the (111) wafer. The difference in defect density between (100) and (111) wafers is also discussed.
Two Kinds of Boundary Motions in Thin Ferroelectric Smectic C* Liquid Crystals
Authors: Ishikawa Ken , Uemura Tsuyoshi , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

The switching process in thin ferroelectric liquid crystal cells under low frequency triangular wave is studied. It is pointed out that there exist three switching processes which are classified into two kinds of boundary motions. One is attributed to an interior 2π disclination motion without changing surface molecular orientation, while the other to a reversion of C-directors on a top and bottom surface which may accompany a surface disclination motion. The field induced motion of a disclination loop separating two kinds of twisted states is discussed by taking into account a structural asymmetry of ±2 π wedge disclinations.
Correspondence between Stroboscopic Micrographs and Spontaneous Polarization Measurements in Surface Stabilized Ferroelectric Liquid Crystal Cells
Authors: Ouchi Yukio , Uemura Tsuyoshi , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

Dynamic process of molecular reorientation in SSFLC cells is studied under a triangular wave by observing a current due to a polarization realignment and by taking stroboscopic micrographs simultaneously. There appear two peaks in the current signal, which correspond to stroboscopic observations of a uniform color change and a spotted pattern, respectively. The first peak originates from both a surface and interior molecular reorientations associated with a transition from a uniform state to a twisted one. The second peak is attributed to a subsequent change to the other uniform state caused by a molecular reorientation at another surface.
Measurements of Compositional Change in Semi-Insulating GaAs Single Crystals by Precise Lattice Parameter Measurements
Authors: Takano Yukio , Ishiba Tsutomu , Matsunaga Nobutoshi , Hashimoto Norikazu
Published: November 2005

Precise lattice parameter measurements have been made for semi-insulating GaAs, and it is found that the lattice parameters vary greatly (order of 10-4 Å) among GaAs wafers and in a wafer. This variation of lattice parameter is closely related to the threshold voltage of the FETs, which are made by direct ion implantation on the crystal. The change of the lattice constant is probably caused by the interstitial As atoms, and a slight change of crystal growth condition may cause its variation in the wafer. Variation of the As concentration affects the threshold voltage of MESFETs when they are made by direct ion implantation.
A Model for the Staebler-Wronski Effect Based on Charged Impurities
Authors: Ishii Nobuhiko , Kumeda Minoru , Shimizu Tatsuo
Published: November 2005

We propose a model for photo-induced changes for Si-based amorphous semiconductors, in which the distance between the impurity atom and the Si atom changes according to charge state.
in situ Phosphorus-Doped Silicon Film Depositions by Magnetron Sputtering in Phosphorus Vapor
Authors: Okamoto Akio , Serikawa Tadashi
Published: November 2005

In situ phosphorus-doped silicon film deposition by sputtering in phosphorus vapor is presented. The phosphorus vapor is generated by heating solid red phosphorus in which the crucible is mounted in an rf planar magnetron sputtering system. Phosphorus is successfully in situ doped during deposition. Silicon films with phosphorus concentrations of up to 8.0×1021 cm-3 are obtained by controlling the crucible temperature. It was found that the deposition rate increases with increasing crucible temperature.
Hall Effect in Plasma Current Sheet Configuration
Authors: Yagi Yasuyuki , Kawashima Nobuki
Published: November 2005

A Plasma current sheet is produced and its basic properties are investigated in order to study the magnetic field line reconnection. It is discovered that fairly intense Hall electric field and Hall current exist. The Hall electric field increases as the thickness of the plasma current sheet decreases. The Hall current forms eddies around the plasma current sheet as expected theoretically. These facts can be applied to the equilibrium and reconnection of the current sheet.
Magnetic Anisotropy of Amorphous Gd-R-Co (R=Tb, Dy, Ho, Er) Films
Authors: Sato Ryuji , Saito Nobuo , Togami Yuji
Published: November 2005

Dependence of anisotropy constants K
u on rare earth atoms in rare earth-transition metal amorphous films was studied. To minimize the influence of the preparation condition on K
u, Gd-R-Co (R=Tb, Dy, Ho, Er) films in which the compositions of R are small were chosen and the magnetic torque was measured. It became clear that even in amorphous films, K
u is mainly determined by the single atomic character of an added rare earth element. This result suggests that the direction of 4f electron clouds may be aligned through a structural anisotropy such as pair-ordering or an anisotropic microstructure.
Novel Gas Detection Method by Metal-Insulator Conglomerate
Authors: Komiyama Hiroshi , Hayashi Atsushi , Inoue Hakuai
Published: November 2005

Ultra-fine silver particles of a nominal size of 4 nm were dispersed in a a porous structure of SiO2 by a wet chemical reaction method. This conglomerate changed its electric resistance by the kind of the ambient gases and can be used as a gas-detecting element. The electric response to the exchange between oxygen and ethylene containing atmospheres was suitably called switching, which was quite rapid and had a threshold voltage. The switching was reversible and repeatable, showing a memory effect.
A Study of the Equilibrium Trajectory of the Superconducting Magnetic Levitation System for the Absolute Determination of the Magnetic Flux Quantum
Authors: Shiota Fuyuhiko , Hara Ko
Published: November 2005

A study of the equilibrium trajectory of the superconducting magnetic levitation system is in progress for the absolute determination of the magnetic flux quantum φ0. The temporary reproducibility of the evaluation factor K' is about 100 ppm. Problems concerned with higher reproducibility turned out to be the fluctuation of the environmental magnetic field and the stability of the SQUID system in controlling the flux-up process.
Level-Crossing Problem of a Gaussian Process Having Gaussian Power Spectrum Density
Authors: Mimaki Tadashi , Myoken Hiroshi , Kawabata Tsutomu
Published: November 2005

The distribution density of the level-crossing interval lengths is experimentally studied for a Gaussian random process having Gaussian power spectrum density. The multi-peak property of the density does not appear for a Gaussian-lowpass spectrum, although it does for a Gaussian-bandpass spectrum. This situation is different from the cases of Butterworth spectra, in which the multi-peak property always appears both for lowpass and bandpass processes. In addition to the disappearance of the multi-peak property, the result of the fluctuation of the number of the crossings leads to a conclusion that a Gaussian process having Gaussian-lowpass spectrum is highly random.
(110) Orientation of Vacuum Evaporated Ag Deposits on NaCl Surfaces in the Atmospheres of Inactive Gases
Authors: Hoshi Ichii , Ogura Iwao
Published: November 2005

Ag of 99.99% purity was evaporated onto the cleavage surface of NaCl in He, Ar or Kr gas atmosphere of pressures lower than 10 Pa in a conventional high vacuum chamber. The deposit films (about 5 nm in mean thickness) were examined with an electron microscope. The epitaxial growth of the deposits was observed at room temperature of the substrate. The orientations were [001](110)Ag//[100](001)NaCl, [001](110)Ag//[010](001)NaCl and/or [100](001)Ag//[100](001)NaCl. The structure of the deposit particles suggests that the particles of (110) orientation are nucleated through the mechanism of decahedron.
Dichroic Dyes for Guest-Host Liquid-Crystal Cells
Authors: Seki Hidehiro , Uchida Tatsuo , Shibata Yukio
Published: November 2005

To clarify the relation between a molecular structure and an order parameter of a dichroic dye of a guest-host liquid-crystal cell, a ratio l/d of a length l to a diameter d of a circumscribed cylinder of the dichroic dye is used as a parameter. Experimental results clarify that there exists an obvious correlation between l/d and an order parameter of a long axis of the dye molecule; information is obtained on ordering state of the dye dissolved in the liquid crystal, especially the performance of flexible parts of the dye molecule.
Electrochromism of Metal-Free Phthalocyanine Langmuir-Blodgett Films
Authors: Yamamoto Hiroshi , Sugiyama Takashi , Tanaka Masaichi
Published: November 2005

A metal-free phthalocyanine film was prepared by Langmuir-Blodgett (LB) technique. It was observed for the first time that the LB film deposited on a ITO/glass showed electrochromic color changes in aqueous solutions of KCl. The color of the film was changed from original blue-green to purple-red in an oxidation process, and to dark-purple in a reduction process. The color changes observed in the LB film were quite similar to those in lantanoid-diphthalocyanine evaporated films. On the contrary, the annealed LB film, of which the structure was dimeric-like, did not show any electrochromic color changes.
A New MOS Phototransistor Operating in a Non-Destructive Readout Mode
Authors: Matsumoto Kazuya , Nakamura Tsutomu , Yusa Atsushi , Nagai Shohei
Published: November 2005

A new MOS phototransistor with high optical gain and non-destructive readout operation is proposed as a photosensor in an imaging device. The principle of this device is a conduction mechanism whereby an incident light changes the surface potential under the MOS gate and the electron current flowing in a buried channel is modulated by the surface potential. The device has a saturation exposure value of 0.1 lx·s, saturation output voltage of 500 mV at V
DD=2 V, the dynamic range of 50 dB with no signal processing and non-destructive readout operation.
Electron Traps due to Defect-Impurity Complexes Induced by the Deformation of Epitaxial GaAs Grown on Si-Doped Substrate
Authors: Yamamoto Norio , Hasegawa Fumio , Onomura Masaaki , Nannichi Yasuo
Published: November 2005

Dependence of deformation induced deep levels on substrate impurities and deformation conditions was studied. Electron traps such as EB4 and EB6 were dominantly induced when undoped VPE GaAs grown on Si-doped substrates was deformed at temperatures higher than 600°C, whereas EL2, HL2(LPE-B) and Cu levels were dominant in deformed VPE layers on Cr-doped substrates. These results indicate that the deformation induced defects easily make complexes with impurities in the substrates, and that the EB4 and EB6 are not simple defects but are complexes with Si impurities.
Laser Irradiation Effects on the Gas Permeability through Polymer Films
Authors: Wada Kazuhiro , Uehara Yasushi , Yamaguchi Hiromi , Nakasaki Yasushi , Ohmori Fumio , Nishimura Kenshi , Yamamoto Masaki
Published: November 2005

Gas permeabilities through specimens of tetrafluoroethylene and hexafluoropropylene copolymer (FEP) and of polyethylene (PE) have been investigated. With dense films, the permeability is enhanced by cw CO2 laser irradiation, while with inflated films, the permeability is suppressed by the irradiation. These effects seem to be closely related to the relation of the molecular size of penetrant to the gap between the polymer chains. If the molecular diameter is larger than the gap, enhancement of the permeation occurs, and if it is smaller, suppression takes place.
Gettering Effects of B2O3 Encapsulant on Mg and Ca Impurities in LEC InP-Growth
Authors: Kubota Eishi , Katsui Akinori
Published: November 2005

Gettering effects have been investigated for doped Mg- and Ca-impurities in liquid encapsulated Czochralski (LEC)-grown InP single crystals. Impurity analyses were carried out for Mg- and Ca-doped InP starting materials, LEC-grown crystals and residual B2O3 encapsulants. It was found that Mg and Ca could be removed as oxide from the melt due to a chemical reaction with a B2O2 encapsulant during growth.
Electrical Conduction of Poly-P-Xylylene Thin Films on Si
Authors: Takai Yoshiaki , Mori Tatsuo , Hayase Yoshihiko , Mizutani Teruyoshi , Ieda Masayuki
Published: November 2005

Electrical conduction of poly-p-xylylene (PPX) polymerized on n- or p-type silicon wafers was investigated. The electric current in a metal-PPX-Si structure was much higher than that in a metal-PPX-metal system and showed a rectifying property depending on the type of Si substrate.
Lateral Mode Localization in Multistripe Laser Diode
Authors: Nishi Kenichi , Lang Roy
Published: November 2005

Possibility of stable phase-locked operation in a multistripe laser diode (MSLD) has been investigated through numerical analysis of lateral modes in a refractive index guided MSLD with two stripes. It has been found that even a very slight irregularity in periodic stripe structure can cause severe localization of individual lateral modes into a single stripe of the multistripe laser cavity. The localization will cause spatial hole-burning and consequent simultaneous oscillation of many lateral modes, which is equivalent to break-down of the phase-locking.
Lateral Solid-Phase Epitaxy of Vacuum-Deposited Amorphous Si Film over Recessed SiO2 Patterns
Authors: Kunii Yasuo , Tabe Michiharu
Published: November 2005

A single-crystal silicon-on-insulator structure had been fabricated by lateral solid-phase epitaxy (L-SPE) of vacuum-deposited amorphous Si (a-Si) film on Si (100) substrate with SiO2 patterns. It is essential in L-SPE of vacuum-deposited a-Si that the substrate surface be planarized by recessing SiO2 patterns. A 7µm-wide single-crystal area over irecessed SiO2 was grown by low temperature annealing (575°C, 20 h). Only a polycrystalline area was formed over the unrecessed SiO2 pattern. This is probably because of voids or the large stress field in a-Si film at the pattern edge step.
Electrical Properties of p-Type Hydrogenated Amorphous Silicon-n-Type Crystalline Gallium Arsenide Heterojunctions
Authors: Mimura Hidenori , Hatanaka Yoshinori
Published: November 2005

Electrical properties of heterojunctions consisting of p-type hydrogenated amorphous silicon and n-type crystalline gallium arsenide were investigated by measuring current-voltage characteristics and their temperature dependence. The forward currents whose slopes were kept almost constant for various temperatures increased exponentially with increasing applied voltage. It was found that the carrier injection mechanism through this junction was essentially the same as that for hydrogenated amorphous silicon/crystalline silicon heterojunction.
SEM-EBIC Investigations of Semi-Insulating Undoped LEC-GaAs
Authors: Tokumaru Yozo , Okada Yasumasa
Published: November 2005

Semi-insulating undoped liquid encapsulated Czochralski GaAs is investigated by taking the image of electron beam induced current. It is found that well resolved images of crystal defects are observed by applying a high bias voltage of about 10–50 V to the specimen with a Schottky electrode under an electron beam current of (0.5–5)×10-10 A at an accelarating voltage of about 10–20 kV.
Effect of Incident Light Illumination Shape on Responsivity of GaAs MESFET Photodetector
Authors: Umeda Tokuo , Cho Yoshio
Published: November 2005

Photoresponsivity of a GaAs MESFET is investigated. By matching the incident light illumination shape to the electrode shape of the device, an improvement of a factor ∼3 in the photoresponsivity was observed. This suggests that the photoresponsivity of GaAs MESFET's is substantially due to a channel current caused by a direct optically-induced modulation of depletion layer.
Gallium and Hydrogen Ion Irradiation during GaAs Molecular Beam Epitaxy
Authors: Kondo Naoto , Kawashima Minoru , Sugiura Hideo
Published: November 2005

Crystallographic, electrical and optical characteristics are investigated for GaAs films grown by molecular beam epitaxy with gallium and hydrogen ion irradiation. Through growth experiments over a tungsten grating, ion irradiation is found to enhance surface atom migration. The optimum energy of H2
+ irradiation for the overgrowth is found to be 100 eV. However, all the ion irradiated films with the ion energy of 0.1–5 keV are highly resistive in spite of a Sn concentration of 3×1017cm-3. 77 K photoluminescence (PL) of as-grown films cannot be observed. It is concluded that ion irradiation gives rise to detrimental defects in the grown layer. These defects are produced by the momentum transfer of bombarding ions to a growing surface.
Solid State Optical Switching and Memory Element with Conducting Polymer Controllable by Both Electric Field and Light Irradiation
Authors: Yoshino Katsumi , Ozaki Masanori , Sugimoto Ryu-ichi
Published: November 2005

With an irradiation of light on an element with a structure of nesa glass/conducting polymer/polymer matrix containing optically dissociative material/nesa glass, a remarkable spectral change is observed corresponding to optically induced dopings of dissociated or decomposed fragments into the conducting polymer. By the electrochemical undoping of this optically doped element, its color returns to the origirnal one. Using a similar element structure, electrochemical doping and undoping are also successfully performed.
Proximity Annealing of Sulfur-Implanted Gallium Arsenide Using a Strip Heater
Authors: Banerjee S. , Baker J.
Published: November 2005

A graphite strip heater has been employed for rapid (∼30 s) thermal annealing (RTA), at temperatures between 850 and 1150°C, of Cr-doped GaAs implanted with 120 keV 32S+ with doses between 1013 and 1015 cm-2. In order to minimize the incongruent evaporation of As, proximity anneals were employed by protecting the implanted samples with GaAs cover pieces. RTA yields electrical activation and donor mobilities better than or comparable to furnace annealing, with less redistribution of the implanted S and background Cr.
Silicon Doping in InP Grown by Metalorganic Vapor Phase Epitaxy Using Silane
Authors: Oishi Mamoru , Nojima Shunji , Asahi Hajime
Published: November 2005

Si-doped InP were grown by metalorganic vapor phase epitaxy (MOVPE) using silane (SiH4). Room temperature electron concentrations of up to 7×1018 cm-3 were successfully achieved with good doping controllability. The growth of undoped high-purity InP (n ∼2×1015 cm-3) was observed immediately after the growth of heavily-doped InP (n ∼2×1018 cm-3). This indicates that SiH4 has no “memory effect”, though the memory effect has been reported for H2Se. The optical properties are comparable with S- or Se-doped InP grown by MOVPE. These results show that the Si from SiH4 is a useful n-type dopant for the MOVPE growth of InP.
ZnSe:Mn DC-Electroluminescent Cells Using Di-π-Cyclopentadienyl Manganese as a New Manganese Source Fabricated by Plasma-Assisted MOCVD
Authors: Mino Naoki , Kobayashi Masakazu , Konagai Makoto , Takahashi Kiyoshi
Published: November 2005

Al/ZnSe:Mn/ITO (indium tin oxide) dc-electroluminescent cells were fabricated by plasma-assisted organometallic chemical vapor deposition. As a new manganese source, di-π-cyclopentadienyl manganese [(C5H5)2Mn] was successfully used for the first time.
EXAFS Monitored by Elastic Photoemission
Authors: Fujikawa Takashi , Usami Seiji
Published: November 2005

Two methods are proposed to measure EXAFS by monitoring the direct photoemission from a solid sample as a function of photon energy for a randomly oriented sample. One is to measure it in the special direction, at the magic angle, and the other is to measure the average intensity over a hemisphere. For a fixed sample, one cannot expect to measure EXAFS by monitoring the direct photoemission.
Growth of Single Domain GaAs on 2-inch Si(100) Substrate by Molecular Beam Epitaxy
Authors: Nishi Seiji , Inomata Hiroki , Akiyama Masahiro , Kaminishi Katsuzo
Published: November 2005

Good surface morphological single domain GaAs films were successfully grown on a whole area of 2-inch Si(100) substrates by molecular beam epitaxy (MBE). Si substrates were first thermally cleaned at 850°C, 100 Å GaAs buffer layers were then grown at low substrate temperatures and, finally, 1.5 µm GaAs layers were grown at 600°C. It was found that the first thermal cleaning of Si is important in growing single domain GaAs and the growth temperatures of the buffer layer had to be low to get a good morphological surface.
Polyacetylene Battery with Polymeric Solid Electrolyte
Authors: Nagatomo Takao , Kakehata Hidehiko , Ichikawa Chiaki , Omoto Osamu
Published: November 2005

The rechargeable all-plastic battery was fabricated using the (CH)
x
film as the electrode active material and PVDF·LiClO4·PC (LiClO4/PC in polyvinylidene fluoride (PVDF)) film as the electrolyte. (CH)
x
/PVDF·LiClO4·PC/(CH)
x
battery exhibited an open-circuit voltage of 3.4 V and an initial short-circuit current of 10 mA (both electrodes; ca. 8 mg, doping level y=0.004). The maximum power density for this all-plastic battery was 1.1 kW/kg and an energy density of 6.5 Wh/kg (doping level y=0.004, weight of (CH)
x
electrodes; ca. 8 mg). This battery was investigated for 50 charge-discharge cycles, although doping levels were shallow (y=0.001). The coulombic efficiency was 53%.
Novel Structure GaInAsP/InP 1.5–1.6 µm Bundle Integrated-Guide (BIG) Distributed Bragg Reflector Laser
Authors: Tohmori Yuichi , Jiang Xiao , Arai Shigehisa , Koyama Fumio , Suematsu Yasuharu
Published: November 2005

A novel structure, 1.5–1.6 µm GaInAsP/InP bundle integrated guide (BIG) distributed Bragg reflector (DBR) laser is presented. The device was operated under CW condition at room temperature with low threshold current. Stable single mode operation was obtained at up to twice the threshold current. The significance of this structure is that the step at the joint between two waveguide regions, such as the active and passive DBR regions, is negligible which results in easy fabrication of buried heterostructure. Theoretical high coupling efficiency of 95–99% with largr fabrication tolerance and higher optical confinement in the active layer is possible.
5.6 ps Gate Delay All Refractory Josephson OR Gate with Modified Variable Threshold Logic
Authors: Kotani Seigo , Fujimaki Norio , Imamura Takeshi , Hasuo Shinya , Yamaoka Toyoshi
Published: November 2005

The modified variable threshold logic (MVTL) OR gate has a wide operating margin of ±43% and occupies a small area of 45×65 µm2. We made this gate with all refractory material including Nb/Al-AlO
x
/Nb junctions and Mo resistors. A chain of 5-stage MVTL OR gate was fabricated. The junction diameters were 4 µm and 7 µm, and critical current density was 1400 A/cm2. The minimum gate delay of 5.6 ps/gate was measured using a Josephson sampler.
Highly Conducting Polypyrrole Prepared by Electrochemical Oxidation Method in Aqueous Solution
Authors: Satoh Masaharu , Kaneto Keiichi , Yoshino Katsumi
Published: November 2005

Conducting polypyrrole films with electrical conductivity higher than 400 S/cm have been prepared by the simple electrochemical oxidation method in aqueous solution with high electrolyte concentration. It has been also found that the conventional surfactants can be used successfully to prepare the high quality polypyrrole film.
Raman Scattering Studies on Hydrogenated Amorphous Silicon Prepared under High Deposition Rate Conditions
Authors: Sakata Isao , Okazaki Satoru , Yamanaka Mitsuyuki , Hayashi Yutaka
Published: November 2005

We have made Raman scattering studies on hydrogenated amorphous silicon (a-Si:H) prepared at high deposition rates ranging from 10–105 A/s. The full width of half maximum of the TO-like band, ΔωTO, increases with the increase in the deposition rate, r
g, which implies an increase in the structural disorder of a-Si:H with the increase in r
g. However, the degree of such increase is small when compared with those observed in a-Si:H alloy materials such as amorphous silicon carbide and amorphous silicon nitride. We have found that the value of ΔωTO is correlated with the B value (the square of the slope of √αh ν versus h ν plot).
A New Heterostructure for 2DEG System with a Si Atomic-Planar-Doped AlAs-GaAs-AlAs Quantum Well Structure Grown by MBE
Authors: Hiyamizu Satoshi , Sasa Sigehiko , Ishikawa Tomonori , Kondo Kazuhiro , Ishikawa Hideaki
Published: November 2005

Using Si atomic-planar-doping technology, a new heterostructure, called “Planar-Doped Quantum Well (PD-QW) Heterostructure”, which has a single Si-doped Ga plane with sheet concentration of 0.6–4 ×1012 cm-2 in an AlAs-GaAs-AlAs quantum well structure as a 2DEG supplying layer was developed. It exhibited 2DEG mobility of 8.7 ×104cm2/Vs at 77 K with sheet concentration of 1.0 ×1012cm-2, in addition to much reduced persistent photoconductivity at low temperatures. The sheet resistivity of the 2DEG layer in this material (about 70 Ω/\Box at 77 K) is the lowest observed so far in selectively doped single-interface heterostructures.
Chalcogenide Amorphous Semiconductor Diodes
Authors: Okano Shuichi , Suzuki Masakuni , Imura Takeshi , Hiraki Akio
Published: November 2005

Thin film diodes with Al/a-As2Se2Te/Sb structures were fabricated by vacuum deposition. Al ions were found to diffuse into a-As2Se2Te films below the glass transition temperature. Measurements of ac conductance and capacitance of the diodes revealed that they consist of two layers of different resistivity which correspond to undoped and Al-doped layers. The upward shift of the Fermi level due to Al doping was inferred from the variation of the forward and backward current with time. Accordingly, the p-n junction formed between the undoped p-type layer and the Al doped n--layer is responsible for the rectification.
Predicted Extremely High Mobilities of Two-Dimensional Electrons in AlGaSb/GaSb and AlInAsSb/InAs Single Heterostructures
Authors: Takeda Yoshikazu , Ichimura Masaya , Sasaki Akio
Published: November 2005

Mobilities limited by ionized remote impurity scattering are calculated for two-dimensional electrons at the interfaces of new heterostructures of AlGaSb/GaSb and AlInAsSb/InAs at low temperature. It is shown that both the mobilities and the conductivities of the electrons in these heterostructures are about twice higher than those in an AlGaAs/GaAs heterostructure with the same barrier height and the same remote impurity concentrations.
AlGaAs/GaAs Buried Multiquantum Well Lasers with a Reactive Ion Etched Window Facet
Authors: Semura Shigeru , Ohta Tsuneaki , Kuroda Takao , Nakashima Hisao
Published: November 2005

The reactive-ion etching (RIE) process in fabricating mirror facets for AlGaAs/GaAs buried multiquantum well (BM-QW) lasers has been developed. The lasers have a window structure where a mirror is formed by RIE. Window and BM-QW structures are fabricated by Zn-diffusion-induced disordering. Because of no carrier injection, the damage caused by RIE does not affect the characteristics of the lasers. The lasers having one facet formed by RIE and the other by cleaving operate in the fundamental transverse mode. A low threshold current (25 mA) and high external quantum efficiency are comparable to those of cleaved lasers.
Room Temperature Observation of Differential Negative Resistance in an AlAs/GaAs/AlAs Resonant Tunneling Diode
Authors: Tsuchiya Masahiro , Sakaki Hiroyuki , Yoshino Junji
Published: November 2005

A resonant tunneling diode having AlAs/GaAs/AlAs double barrier structure is designed to enhance the resonant tunneling current component and to suppress the excess current component which is believed to dominate the transport at high temperatures. Based on this design, a diode structure with optimized parameters is prepared by careful molecular beam epitaxial growth, in which the dopant incorporation into the well layer and the interface asperities are minimized. The AlAs/GaAs/AlAs diodes thus fabricated were found to exhibit differential negative resistance at room temperature for the first time.
Properties of Amorphous Silicon Nitride Prepared at High Deposition Rate
Authors: Nishibayashi Yoshiki , Imura Takeshi , Osaka Yukio , Shizuma Kiyoshi , Nishiyama Fumitaka
Published: November 2005

A high deposition rate of more than 2.2 nm/s was achieved for hydrogenated amorphous silicon nitride film by applying the substrate tuning method to glow-discharge decomposition of SiH4+NH3. The atomic ratio N/Si (1.1±0.1) in the film is nearly constant, irrespective of the increase of deposition rate. The valence-electron density and atomic density increase and buffered HF etch rate decreases with deposition rate. This high rate deposition method improves density in amorphous silicon nitride films.