bluuebunny/crossref_metadata_2025 huggingface dataset:
The Raman Spectrum of Carbon in Silicon
Authors: Forman R. A. , Bell M. I. , Myers D. R. , Chandler-Horowitz D.
Published: November 2005

Raman spectroscopy is used to characterize carbon-doped silicon samples prepared by ion implantation and pulsed laser annealing. Sharp lines are observed in the Raman spectra due to the 12C local mode at 604±1 cm-1 and the 13C local mode at 586±1 cm-1. Identical spectra are obtained from a given carbon implant whether it is annealed using a 10 ns pulsed ruby laser or the significantly longer pulse of an R6G dye laser. It is shown that Raman spectroscopy has sufficient sensitivity to detect striated carbon distributions in as-grown commercial silicon. Finally, at high carbon density, where the local modes begin to broaden in the implanted and laser-annealed samples, a disorder-induced first-order Raman spectrum is observed produced by the mass defect of the substitutional carbon.
Resistivity Lowering of Palladium Silicide Film due to Post-Annealing
Authors: Kikuchi Akira , Hinode Kenji
Published: November 2005

Resistivity, X-ray diffraction and transmission electron microscope measurements were performed on as-formed and post-annealed palladium silicide films. As the post-annealing temperature was increased, resistivity of the films decreased, and X-ray diffraction and transmission electron microscope measurements showed strong preferred orientation of (0016) reflection and grain growth of palladium silicide, respectively. It is thought that these structural changes affect the resistivity lowering of post-annealed palladium silicide film.
Ridge Type Microfabrication by Maskless Ion Implantation of Si into SiO2 Film
Authors: Shiokawa Takao , Miyamoto Isao , Kim Pil Hyon , Ochiai Yukinori , Masuyama Akio , Toyoda Koichi , Namba Susumu
Published: November 2005

A ridge type pattern can be fabricated by selective chemical etching after maskless ion implantation of Si++ into SiO2 film. The etchant is buffered HF, and maskless ion implantation into SiO2 film is carried out by a 100 kV focused ion beam apparatus with the ion dose from 2×1016 to 3×1018 cm-2. The ridge line width increases with the ion dose. The cross section of the ridge type pattern is a trapezoidal shape at a wide range of ion dose, while it is a triangular shape at a lower ion dose. The minimum line width of 50 nm with height of about 50 nm is obtained for a conventional CVD SiO2 film.
Plasma Etching of CVD Grown Cubic SiC Single Crystals
Authors: Dohmae Shinichi , Shibahara Kentaro , Nishino Shigehiro , Matsunami Hiroyuki
Published: November 2005

Plasma etching of CVD grown cubic SiC single crystals with CF4+O2 mixture gas was investigated for the first time. The O2 gas composition, rf power and pressure dependence of the etching rate were clarified. The maximum etching rate was obtained with the O2 gas composition of 67%. The ratio of the etching rate between cubic SiC and Cr was found to be about 8.3, which indicates Cr as a good etching mask for cubic SiC.
Coloration of Sapphire by Metal-Ion Implantation
Authors: Saito Yukinori , Kumagai Hideo , Suganomata Shinji
Published: November 2005

Relations between the coloration of synthetic sapphire and impure elements introduced by ion implantation were investigated. Ion species used for implantation were Nb+, Fe+, Cu+, Co+, Ti+, Cr+. Doses of metal ions were 1 ×1017 ∼3 ×1017 ions/cm2. The color of the parts implanted with Fe+ or Co+ and subsequently annealed at 1000°C for 3 h was yellowish-brown or light blue, respectively. Transparencies in the visible range and the depth profiles of Fe and Co of the parts implanted with Fe+ or Co+ ions were measured.
A Simple Measurement of the Properties of Superconducting Nb3Ge Films
Authors: Akinaga Masahiro
Published: November 2005

In superconducting phase transition, sputtered Nb3Ge thin films equipped with a small-sized, closed-cycle, helium-gas refrigerator have been observed. By the use of a specially devised sample holder, Nb3Ge thin films on a sapphire substrate have been capable of being cooled as low as 11 K, and the electric resistance of high-T
c superconducting thin films can be measured without liquid helium in quite a simple, easy way. The development of this measuring technique will be very useful to small-scale laboratories which do not have a supply system of liquid helium.
Formation of Copper Phthalocyanine Polymer Films by the Double Source Evaporation of Tetracyanobenzene and Copper
Authors: Yudasaka Masako , Nakanishi Kazumi , Hara Takao , Tanaka Masatoshi , Kurita Susumu
Published: November 2005

By the double source evaporation of Cu and tetracyanobenzene, films are obtained which are verified to be made of copper phthalocyanine polymer by comparing their IR and VIS/UV spectra with those of copper phthalocyanine (CuPc). The π→π* absorption bands observed around 600 nm in the spectrum of CuPc almost fade away in that of the obtained film because the π orbitals spread all over the polymer. The conductivity at room temperature is about 2×10-4 Scm-1. The activation energy calculated from temperature dependence of the conductivity is about 0.055 eV.
Experimental Test of the Composite Josephson Device
Authors: Nakanishi Masakazu , Hara Ko
Published: November 2005

A circuit composed of superconductive loops of 4 Josephson junctions (abbreviated as JJ) or more with infinitesimal loop area is named as a Composite Josephson device (abbreviated as CJD). Its numerical analysis has been reported before. One of the CJD, a 3 terminal 6 JJ loop device, is fabricated by the microbridge utilizing step edge technology and its experimental tests are reported in this paper. Its numerical analysis is proved by the experimental tests.
Optical Recovery of Photoquenching at the Midgap Electron Traps (EL2 Family) in GaAs
Authors: Mochizuki Yasunori , Ikoma Toshiaki
Published: November 2005

Partial optical recovery from the metastable state to the normal state was observed at the EL2 centers in liquid encapsulated Czochralski GaAs from photocapacitance measurements. It was found that the optical recovery spectrum has a peak at 0.855 eV with FWHM of 0.13 eV and that the recovery process has a strong non-exponentiality. Photoquenching transients at the optically recovered levels show that they are not regarded as a single level. The transition scheme between these states is found to be inconsistent within a simple configuration coordinate diagram model but is more likely to be due to various defect reactions in sizable defects. The result supports an arsenic cluster model for the origin of the EL2 family which we have already proposed.
Dependence of Deep Level Concentration on Nonstoichiometry in MOCVD GaAs
Authors: Fujisaki Yoshihisa , Takano Yukio , Ishiba Tsutomu , Sakaguchi Harunori , Ono Yuuichi
Published: November 2005

Investigations have been made of deep levels in undoped GaAs crystals grown by metal organic chemical vapor deposition (MOCVD) on liquid encapsulated Czochralski (LEC) GaAs wafers. The dependence of electron trap level EL2 concentration and a lattice constant on nonstoichiometric composition of epitaxial GaAs crystals has been clarified by changing the mole flux ratio of arsine (AsH3) to trimethyl gallium (TMG), [AsH3]/[TMG], from ten to eighty. The dependence of EL2 concentration and a lattice constant on [AsH3]/[TMG] strongly suggests that an interstitial arsenic atom or group of interstitial arsenic atoms leads to development of EL2.
Formation of High Resistance Region in GaAs by Ga Focused-Ion-Beam Implantation
Authors: Nakamura Kazuo , Nozaki Tadatoshi , Shiokawa Takao , Toyoda Koichi , Namba Susumu
Published: November 2005

It was experimentally confirmed for the first time that Ga focused-ion-beam maskless implantation into n-GaAs is effective to form a submicron high resistance region, even though 850°C annealing was made after Ga implantation. For conductive layers formed by 30 keV, 5×1012 cm-2 Si implantation, a critical Ga ion dose for obtaining the high resistance region was found to be about 3×1013 cm-2. Estimated resistivity in the high resistance region was around 1×104 Ω·cm with breakdown voltage of about 30 V. Residual radiation damage seems to be one of the main factors in the formation of the high resistance region.
Near Room Temperature CW Operation of 660 nm Visible AlGaAs Multi-Quantum-Well Laser Diodes Grown by Molecular Beam Epitaxy
Authors: Iwamura Hidetoshi , Saku Tadashi , Hirayama Yoshiro , Suzuki Yoshifumi , Okamoto Hiroshi
Published: November 2005

CW operation of 0°C at a wavelength of 660 nm was achieved by AlGaAs multi-qunatum-well laser diodes which were fabricated from a wafer grown by molecular beam epitaxy. With a 10 µm-wide stripe geometry laser structure, the threshold current density was as low as 5.5 kA/cm2 (pulse) and 8 kA/cm2 (cw). The shortest wavelength for pulse operation was 645 nm at 20°C.
The Role of Gallium Antisite Defect in Activation and Type-Conversion in Si Implanted GaAs
Authors: Hiramoto Toshiro , Mochizuki Yasunori , Saito Toshio , Ikoma Toshiaki
Published: November 2005

The role of the gallium antisite defect, GaAs, in the activation process of implanted Si in undoped GaAs was investigated by Hall effect and photoluminescence measurements. The activation efficiency increased with increase of the annealing temperature, but an efficiency reduction was observed above 900°C for 0 s hold time annealing and above 850°C for 20 min annealing. Moreover, p-type conversion took place above 900°C for 20 min annealing. It was found from photoluminescence measurements that at high temperatures the density of GaAs was increased to reduce the activation efficiency and eventually to convert the material to p-type. It is pointed out that the density of GaAs in semi-insulating GaAs must be low to attain high activation efficiency. It was also found that co-operative phenomena among C, Si and Ga that occupy arsenic sites appeared at rather high temperatures.
A Model for DX Centers: Bond Reconstruction due to Local Random Donor-Host Atom Configurations in Mixed Semiconductor Alloys
Authors: Kobayashi Keisuke L. I. , Uchida Yoko , Nakashima Hisao
Published: November 2005

A bond reconstruction model for DX centers is proposed. The model assumes the inherent instability in the sp3 covalent bonding between donor and host atoms in the indirect gap regime. This instability is due to the localization of donor bound electrons. The instability results in bond reconstruction which is governed by local host atom configurations around the donor atoms. The DX centers are resultant self-generated donor vacancy pairs.
Identification of the “EL2 Family” Midgap Levels in GaAs
Authors: Ikoma Toshiaki , Mochizuki Yasunori
Published: November 2005

Our arsneic cluster model for the midgap levels (EL2 family) is discussed in more details to account for the data of ESR and related measurements. It is shown that defect states in three fold coordinated amorphous arsenic clusters, namely four fold coordinated arsenic atoms, might give rise to an ESR spectrum which was previously attributed to an arsenic antisite. Moreover, the cluster model is more preferable in explaining complex ESR data which were recently observed. Defect reactions in arsenic clusters may predict peculiar optical properties of the EL2 family which have similarities to those in bulk amorphous arsenic. Motions of dislocations, annealing effects and laser degradation can also be explained by the behavior of excess arsenics (arsenic clusters) in GaAs.
N2 Laser System for Laser Microbeam Cell Surgery
Authors: Kagawa Kiichiro , Kobayashi Hiroko , Yokoi Sadahiro
Published: November 2005

A new method of making a laser microbeam is presented which uses a pulse UV gas laser in which oscillation of the multi transverse mode takes place. N2 laser light passing through a pinhole (diameter of 20 µm) is amplified by an amplifier after the beam is collimated with the aid of a lens (f
1=200 mm). The amplified laser light is then led to a microscope and focused by an objective lens (×20, f
2=8.9 mm). Thus the image of the pinhole is projected onto a specimen with the result that the size of the image is reduced by f
2/f
1. It is demonstrated that a localized hole with a diameter of less than 1 µm is produced on red corpuscles in human blood.
X-Ray Topography Examination of Lattice Distortions in LEC-Grown GaAs Single Crystals
Authors: Kitano Tomohisa , Matsui Junji , Ishikawa Tetsuya
Published: November 2005

We observed lattice distortions in liquid encapsulated Czochralski (LEC)-grown GaAs crystals by double crystal reflection topography. A large variation of lattice orientation due to dislocations was observed in undoped GaAs crystals and at slippage from the wafer periphery in In-doped GaAs crystals, while a large variation of lattice spacing was observed in In-doped GaAs crystals.
Theoretical Gain of Quantum-Well Wire Lasers
Authors: Asada Masahiro , Miyamoto Yasuyuki , Suematsu Yasuharu
Published: November 2005

Gain is given theoretically for quantum-well wire lasers where electrons are confined one-dimensionally. Maximum gain is obtained for a quantum-well wire perpendicular to light propagation, due to anisotropy of the dipole moment. Although the density-of-states is infinite at subband edges, gain remains finite due to the intraband relaxation. Therefore, high gain can be obtained by reducing intraband scatterings. Gain in 100 Å×100 Å Ga0.47In0.53As/InP quantum-well wires is about twice that in 100 Å thick conventional quantum-wells, and reduction of the laser threshold is expected.
Epitaxial Growth of Bi12SiO20 Films by Chemical Vapor Deposition
Authors: Nagao Yasuyuki , Mimura Yoshinori
Published: November 2005

The growth of Bi12SiO20 films on (111) Bi12SiO20 substrates has been attempted by chemical vapor deposition. With the source material combination of Bi metal and silicon alkoxide, transparent epitaxial films have been grown in the wide composition range of x=10.8–17.6, where x denotes the ratio of Bi to Si in the grown films.
Burstein-Moss Effect of PbTe-Pb1-xSnxTe Superlattice
Authors: Ishida Akihiro , Fujiyasu Hiroshi
Published: November 2005

Optical-absorption-edge shifts due to free carrier (Burstein-Moss effect) of PbTe-Pb1-x
Sn
x
Te (x=0.22) superlattices (SLs) were measured at 77 K to determine the band offset of the heterojunction. For the n-type SL, the shift was very small owing to the electron confinement into PbTe wider gap layers resulting from a type-I' band structure. On the other hand, a large shift was observed for the p-type SL owing to the electron confinement into Pb1-x
Sn
x
Te narrower gap layers. Analyzing the optical absorption properties, conduction band edge of the Pb1-x
Sn
x
Te was estimated to be 60 meV higher than that of PbTe.
Flow-Rate Modulation Epitaxy of GaAs
Authors: Kobayashi Naoki , Makimoto Toshiki , Horikoshi Yoshiji
Published: November 2005

We propose a flow-rate modulation epitaxy method which yields high-purity GaAs layers with improved growth rate controllability. This method is based on an alternate gas flow of triethyl gallium (TEG) and arsine (AsH3) by using hydrogen carrier gas. The most characteristic point of this method is that a very small amount of AsH3 is added during the TEG flow period. This small amount of AsH3 suppresses the formation of arsenic vacancies near the growing surface, and thus reduces the incorporation of impurity atoms. As a result, we could obtain high purity GaAs layer at relatively low growth temperatures.
Electrical Properties of Ga Ion Beam Implanted GaAs Epilayer
Authors: Hirayama Yoshiro , Okamoto Hiroshi
Published: November 2005

Resistivity enhancement by 5 orders or more was realized by Ga focused ion beam implantation into n+ and p- GaAs epilayers. For originally n+ epilayers, this resistivity enhancement is maintained after annealing as high as 800°C. However this enhancement disappears after annealing at above 650°C for p+ epilayer. This property makes GaAs high resistive only in a limited area whose minimum dimension is 0.1 µm or less, and is attractive for a device fabrication process to electrically isolate integrated elements.
Synchrotron Plane Wave X-Ray Topography of GaAs with a Separate (+, +) Monochro-Collimator
Authors: Ishikawa Tetsuya , Kitano Tomohisa , Matsui Junji
Published: November 2005

A plane wave X-ray topographic camera was constructed with a separate (+, +) monochro-collimator system at Photon Factory. Undoped and indium-doped GaAs crystals are topographically investigated. For the undoped GaAs, a two-fold symmetric strain field has been observed in a (001) wafer. In the indium-doped sample, a highly stressed region probably produced by the In segregation has been observed.
Dependence of Temporal Behavior of Conoscopic Figures in Nematic Liquid Crystals on Film Thickness
Authors: Yamashita Masafumi
Published: November 2005

The time required to form the conoscopic figure in nematic liquid crystals after the electric field is turned on and off is studied temporally, varying the thickness of the twisted film. The effect of the film thickness on the temporal behavior of the conoscopic figure is remarkable. The film thickness at which the conoscopic figure can be formed fastest is about 9 or 14 µm under 1 V/µm and the formation of the conoscopic figure depends strongly on the electric field strength. Reformation and rotatory motion of the conoscopic figure are observed after the electric field is turned off, and figures similar to those of a biaxial crystal are observed in films of thickness greater than 20 µm.
Nb-Pb-Nb Planar Josephson Junction Fabricated by RIE
Authors: Yoshimori Shigeru , Kawamura Mitsuo
Published: November 2005

Nb-Pb-Nb planar Josephson junctions were fabricated by electron-beam exposure and Reactive-Ion-Etching (RIE) and their response characteristics under millimeter-and submillimeter-wave radiation were investigated. The size of the weak-link was 0.67-1.0 micrometers long, 5.0 micrometers wide and 1000Å thick. The fourth Shapiro step under 70 GHz millimeter-wave radiation could be observed. On the other hand, the planar junctions showed only a bolometric response under 891 GHz submillimeter-wave radiation. In this paper, the characteristics of RIE using a CBrF3 gas as the etchant and an electron beam resist, PMMA, as the mask material are also discussed.
Solutions of Simultaneous Equations for Oxidation Enhanced and Retarded Diffusions and Oxidation Stacking Fault in Silicon
Authors: Yoshida Masayuki , Matsumoto Satoru , Ishikawa Yutaka
Published: November 2005

Equations for oxidation enhanced and retarded diffusions (OED and ORD) and oxidation stacking faults (OSF) in silicon have been solved simultaneously, using experimental results at 1100°C for 1.0×104-2.4×105 s. A simple relation between the concentrations of self-interstitials and vacancies was assumed in order to obtain the solutions. It is concluded that the product of the concentrations of the self-interstitials and vacancies, C
I
C
V, is nearly equal to the value for thermal equilibrium, C
I
0
C
V
0, and that the fractional components of the interstitialcy mechanism for self-, Sb and P diffusions are smaller than 0.5, smaller than 0.5 and larger than 0.5, respectively. This shows that the growth of OSF is caused mainly by the undersaturation of a vacancy, and that the ORD of Sb and the OED of P occur. The time dependences of the supersaturation ratios of the self-interstitials and vacancies were also obtained.
Effect of Ammonium Gas on Electrical Property of Conducting Polymers
Authors: Yoshino Katsumi , Gu Hal Bon
Published: November 2005

Contrary to polyacetylene and polythiophene, the electrical conductivities of poly(p-phenylene) and poly(p-phenylenevinylene) can be increased remarkably by ammonium doping. This can be explained in terms of n-type doping. Diethylamine and triethylamine have also been found to be effective concerning these conducting polymers. The application of this effect as a sensor of gas and odor is also proposed.
Photoelectrochemical Behavior of n-Type Porous-Si Electrodes
Authors: Koshida Nobuyoshi , Koyama Hideki , Kiuchi Yuji
Published: November 2005

A prolonged photoanodic operation of n-type Si in aqueous electrolytes was observed with porous-structure Si electrodes. The n-type porous-Si layers (n-PSL) were formed on n-Si substrates (1-2 Ωcm in resistivity) by anodic treatments in an HF solution. The total output charge Q obtainable from a n-PSL photoelectrochemical cell increased in proportion to the n-PSL thickness d. At d = 50 µm, Q reached 12.5 C/cm2; this was four orders of magnitude greater than was obtained from naked n-Si photoanodes. The H2 evolution rate from the Pt counterelectrode was about 60 µmol/2 h at d = 30 µm. The experimental results of the spectral response suggest an increase in the surface state density of the n-PSL surface with increasing d.
Coherent Anti-Stokes Raman Spectroscopy of Radio-Frequency Discharge Plasmas of Silane and Disilane
Authors: Hata Nobuhiro , Matsuda Akihisa , Tanaka Kazunobu
Published: November 2005

Coherent anti-Stokes Raman spectroscopy has been employed for the diagnosis of rf discharges of silane (SiH4) and disilane (Si2H6). The signal intensities from silane and disilane have been measured as a function of time after switching-on the rf power supplied to SiH4 and Si2H6 gas in a closed reaction chamber. From this measurement, the loss rates of silane and disilane have been determined directly as functions of the rf-power density and gas pressure for the first time. The rate of formation of SiH4 in disilane discharge plasmas has also been determined.
A High Pressure Rolling-Ball Viscometer up to 1 GPa
Authors: Izuchi Masaya , Nishibata Ken
Published: November 2005

A rolling-ball viscometer has been developed for use under high pressures up to 1 GPa. It is proven that the calibration coefficient of the viscometer depends on its inclination angle and that this dependence varies with the diameter ratio of the ball and tube. In order to permit a simultaneous measurement of the density, the viscometer was improved, allowing for the attachment of a potentiometric displacement sensor. The precision of the density measurement is estimated to be ±0.22%. The viscosity data of a pressure-transmitting liquid, di-(2-ethyl-hexyl) sebacate (Univis P12), is presented in the range of pressures up to 800 MPa at temperatures from 6 to 60°C. The accuracy of a viscosity measurement is estimated to be ±0.95%.
A Planarization Technique Utilizing Oxide Flow during H2 Treatment of a SiO2-GeO2 Film
Authors: Ogino Toshio , Amemiya Yoshihito
Published: November 2005

A large oxide flow has been found to appear when a SiO2-GeO2 mixed glass film is treated in a low-pressure H2 gas at 900°C. Simultaneously, the greater part of the GeO2 component is evaporated. The flow mechanism is explained by the diffusion and evaporation of GeO molecules produced by GeO2 reduction. A planarization process utilizing this flow exhibits a large effect at low temperatures in comparison with phosphosilicate-glass flow. The oxide profile after a H2 treatment is no longer changed by a high-temperature treatment. The formed oxide is highly durable against acids. Electrical properties such as the dielectric constant, resistivity, and dielectric strength are comparable to those of a SiO2 film grown by the thermal oxidation of Si. The problem of a small amount of Ge crystallized on the bottom of the oxide layer is controlled by a decrease in the H2 pressure.
Magnetic Anisotropy and Magneto-Optical Properties of Iron Oxide Films
Authors: Urabe Shuji , Numata Takuhisa , Inokuchi Seiji , Sakurai Yoshifumi
Published: November 2005

Iron oxide films were prepared by rf diode sputtering. Magnetic and magneto-optical properties of the iron oxide films are discussed. Perpendicular anisotropy was induced in sputtered iron oxide films (typically K
u=2×105 erg/cm3). This perpendicular anisotropy was lost by annealing in air. The value of the Faraday constant θf was typically 2×104 deg/cm at 633 nm. The absorption coefficient α was 105 cm-1 at 0.4-2.4 µm.
Large Dielectric Relaxations in an Alternate Copolymer of Vinylidene Cyanide and Vinyl Acetate
Authors: Furukawa Takeo , Date Munehiro , Nakajima Kenji , Kosaka Takeshi , Seo Iwao
Published: November 2005

An alternate copolymer of vinylidene cyanide and vinyl acetate has been investigated dielectrically at temperatures above T
g ∼170°C. A remarkable relaxation was observed in the 1 Hz to 10 kHz frequency range due to a separation from coexisting contributions as a result of the dc conductivity. The relaxation time depends upon the temperature in the WLF according to the characteristics of the micro-Brownian motions of molecular segments. The relaxation strength was found to reach 125, resulting in an unusually high dielectric constant. Such a large relaxation strength is an indication of some cooperative effects in relation to dipolar motions. Cooling to below T
g in the presence of a high electric field creates a large remanent polarization which is consistent with the strong piezoelectric activity reported for this copolymer.
Preparation of GaAs and Ga1-xAlxAs Multi-Layer Structures by Metalorganic Molecular Beam Epitaxy
Authors: Tokumitsu Eisuke , Katoh Toshiaki , Kimura Ryuhei , Konagai Makoto , Takahashi Kiyoshi
Published: November 2005

Metalorganic molecular beam epitaxial (MOMBE) growth of GaAs and (GaAl)As using triethylgallium (TEG) and triethylaluminum (TEA) has been studied. N-GaAs/p-GaAs multi-layer structures were prepared by applying an alternating ionization voltage to hydrogen. Single-crystal Ga1-x
Al
x
As ternary alloy with good surface mophology was successfully grown by introducing TEA as an Al source. The epitaxial layers typically showed p-type conduction with a carrier concentration of more than 1018 cm-3, this being due to residual carbon. A (GaAl)As/GaAs multiquantum well (MQW) heterostructure was fabricated by switching TEA and it was observed that the photoluminescence peak energies from the MQW structures were shifted to the higher energy position.
Furthermore, selective growth of GaAs and (GaAl)As on a partly SiO2 masked GaAs substrate was investigated. In the MOMBE growth of (GaAl)As, polycrystalline film was deposited on the SiO2 masked region, while no deposition took place in the growth of GaAs.
Lifetime Measurements of the 83.4 keV and 103.2 keV Levels in 153Eu
Authors: Sakata Akihiko , Yamada Yoshihiro , Ohira Kyozo
Published: November 2005

The half-lives of the 83.4 keV 7/2+ rotational level and the 103.2 keV [411 3/2+] level in 153Eu, lying in the boundary between deformed and non-deformed regions, have been measured by a delayed-coincidence method. The half-life of the former level was estimated from the composite decay spectrum of the 83.4 and 103.2-keV levels; the latter level deexcites mainly by a l-forbidden M1 transition. The results are τ1/2(83.4 keV)=0.77±0.05 ns and τ1/2(103.2 keV)=3.87±0.10 ns; B(M1, 83.4 keV)=(6.2±1.0)×10-3µN
2 and B(M1, 103.2 keV)=(2.1±1.1)×10-3µN
2; and the Weisskopf hindrance factors F
w(83.4 keV)=(2.11±0.34)×102 and F
w(103.2 keV)=(8.9±4.7)×102. The conclusion derived from the B(M1) values is that 153Eu represents two different deformation parameters (ε∼ 0.2 and ε∼ very small) for those two excited modes. This is discussed according to an assumed relation analogous to Δp·Δq∼\hbar.
Frequency Stabilization of CH3OH Laser at 469 µm to Millimeter-Wave Frequency Standard
Authors: Sakurai Toshio
Published: November 2005

Frequency stabilization of an optically-pumped CH3OH laser oscillating in the 469 µm line to a phase-locked 71 GHz reference was investigated. The CO2 pump laser was offset-locked to the 4.3 µm-fluorescence stabilized CO2 laser. A frequency stability σy(τ) of 2×10-11 in terms of the square root of the Allan variance was obtained at 469 µm, where τ is the averaging time. The stability is discussed in conjunction with the dispersion effect of the oscillation frequency due to variation of the pump frequency and also with the oscillation frequency shift due to variation of the pump power.
Circuit to Use a Photon Correlator as a Fast Analog Correlator
Authors: Terui Giichi , Kohno Tomoharu , Fukino Yohichi , Ohbayashi Kohji
Published: November 2005

A simple voltage-to-frequency converter has been made which has a 1-µs sampling time, generates a 25-MHz TTL pulse corresponding to a 10-V analog input, and responds up to a high-cutoff-frequency of 570 kHz. By processing an analog signal with it, a photon correlator has been used as a high-speed analog correlator. Observations of the analog correlation functions of sinusoidal signals and the Johson noise are given.
Velocity-Distribution Functions of Sputtered Atoms Caused by Insufficiently Developed Collision-Cascades
Authors: Matsuda Yoshinobu , Yamamura Yasunori , Honda Chikahisa , Matsubaguchi Satoshi , Maeda Mitsuo , Muraoka Katsunori , Akazaki Masanori
Published: November 2005

Velocity-distribution functions of sputtered iron atoms by argon-ion bombardment at oblique incidence, measured by laser fluorescence spectroscopy, were found to deviate from the Thompson formula at forward ejection angles relative to the incident ions. The effect was identified as being due to, and quantitatively evaluated by, contributions from insufficiently developed collision-cascades.
Low-Resistance Ohmic Contacts to p-GaAs
Authors: Hirano Makoto , Yanagawa Fumihiko
Published: November 2005

A new metal structure consisting of AuZnNi/Ti/Au has been proposed for forming low-resistance ohmic contacts to p-GaAs with a fine-pattern definition. The dependency of the contact resistance on the Ti-layer thickness indicated that an optimum amount of Ti is requred for reducing the contact resistance. A minimun contact resistance (0.3 Ω·mm) was obtained with 150-nm thick Ti attached to Be-implanted p-GaAs at a dose of 6×1013 cm-3.
Roughness Measurement of X-Ray Mirror Surfaces
Authors: Kunieda Hideyo , Hayakawa Satio , Hirano Tatsumi , Kii Tsuneo , Nagase Fumiaki , Sato Naohisa , Tawara Yuzuru , Makino Fumiyoshi , Yamashita Koujun
Published: November 2005

In order to fabricate an X-ray mirror telescope, we investigated the roughness of mirror surfaces using X-ray scattering. With Al-K (8.34Å) X-rays we measured the scattering profiles of plate glass. The spectral structure of surface roughness was revealed by the angular distribution of the X-ray scattering. The power spectral density functions of the surface-height distribution for these materials (except for a gold evapolated surface) were represented by the power-law spectra with power indices ranging from -1 to -2. The rms heights were derived to be 1.8-8.3Å for a wavelength range as expected from the power-law spectrum. The results obtained with this method were found to be consistent with those with an ordinary optical profilometer.
Absolute Intensity of Soft X-Rays of Synchrotron Radiation from the ETL-Storage Ring
Authors: Suzuki Isao H. , Saito Norio
Published: November 2005

The absolute intensity of X-rays in synchrotron radiation from the ETL-storage ring was measured using a proportional counter with a mylar (45 Å region), aluminum (8.3 Å region) or titanium window (2.7 Å region). The measured intensities were compared with those by calculation based on Schwinger's formula. The several parameters necessary for the calculation were obtained using the measured values and data from the literature. A comparison showed that the synchrotron radiation from the ring is suitable as a standard light source in these soft X-ray regions, and it was found that absolute intensity measurements in soft X-ray regions serve as accurate diagnostics for this storage ring.
Measurement of Elastic Constants of MBE Grown (Ga0.5Al0.5)As Mixed Thin Film Crystal by Diffuse X-Ray Scattering
Authors: Kashiwagura Nobuo , Kashihara Yasuharu , Harada Jimpei
Published: November 2005

By a measurement of X-ray thermal diffuse scattering and an analysis based on a least squares fitting procedure, it was demonstrated that a set of elastic constants could be determined for an MBE grown (Ga0.5Al0.5)As mixed crystal of 4 µm thickness. The absolute value ofC11and the ratios of the elastic constants,C12/C11andC44/C11, were determined to be 13.32±0.35 [×1011dyn/cm2], 0.418±0.021 and 0.473±0.013, respectively, for the sample. It turned out that the elastic constants of the mixed thin film crystal was slightly higher than that expected from the linear interpolation between GaAs and AlAs.
Properties of Plano-Concave Ultrasonic Resonator and Application to Velocity Dispersion Measurement
Authors: Bae Jong-Rim , Choi Pak-Kon , Takagi Kenshiro
Published: November 2005

The resonance characteristics of a plano-concave ultrasonic resonator, newly designed for precise measurements of ultrasonic velocity and absorption, were experimentally investigated over a frequency range between 100 kHz and 2MHz using five liquids with various absorption coefficients and acoustic impedances. The instrumental loss of the resonator was determined as a function of the frequency, which is subtracted from the observed resonance width in order to determine absorption in liquids. It was also found that water is the most suitable reference liquid for obtaining the instrumental loss curve of piano-concave resonator. To measure the velocity from the resonance interval, the frequency dependence of the apparent acoustic path length was observed and the results were theoretically described with a composite-resonator model consisting of an ultrasonic transducer, a sample liquid and a metal reflector. To demonstrate the usefulness of the new resonator, the velocity dispersion due to a relaxation effect was observed in methyl cyclohexane.
Effective Mass Reversal on InxAl1-xAs/GaAs Strained-Layer Superlattices
Authors: Kato Hiromu , Iguchi Naoya , Chika Shigeaki , Nakayama Masaaki , Sano Naokatsu
Published: November 2005

Here, we report on the first evaluation of two-dimensional hole masses of GaAs layers in In
x
Al1-x
As/GaAs strained-layer superlattices. The mass change in the valence band of the GaAs layers under a biaxial-layer strain has been determined by comparing the photoluminescence line shape with a theoretical calculation of the spectral dependence of the spontaneous emission rate. Reversals of the effective hole masses parallel to the heterointerfaces are important for evaluating optical transitions in strained-layer superlattices.
Study on the Polarity of Residual Voltage in Polymeric Insulating Films
Authors: Kitani Isamu , Arii Kiyomitsu
Published: November 2005

Residual voltages were measured for seven kinds of polymeric insulating films with brass or evaporated silver electrodes at room temperature. When the circuit was opened at the cathode side, the negative residual voltage was always observed in polyethylene terephthalete (PET), polycarbonate (PC), polystylene (PS) and polypropylene (PP) regardless of the experimental conditions. The positive residual voltage was ovserved in low-density polyethylene (LDPE), high-density polyethylene (HDPE) and ethylene and vinylacetete copolymer (EVA) under conditions which would bring about a double injection.
Superconducting Properties and Phase Analysis of Nb-Si Thin Films Produced by Sputtering
Authors: Ohshima Shigetoshi , Shiba Takashi , Kawanobe Tadashi , Wakiyama Tokuo
Published: November 2005

Nb-Si films were deposited on Nb.84Si.16, Ti3Au and W3Re films with an A15 structure by sputtering. The films with double layers were analyzed using Auger electron spectroscopy. Phase analyses of the sputtered Nb-Si films were carried out by X-ray diffraction studies. The A15 Nb.78Si.22 and Nb.75Si.25 films were grown epitaxially on Nb.84Si.16 and W3Re substrate films. The superconducting transition temperatures of these epitaxial films were found to range between 5 and 9 K.
Observations on Perpendicular Magnetic Recordings of High Recording Densities on Co-Cr Films by the Colloid-SEM Method
Authors: Goto Kimiyoshi , Sakurai Tomoaki , Kitakami Osamu
Published: November 2005

Perpendicular magnetic recordings of 5 to 100 kBPI densities on evaporated Co-24 wt%Cr films of 2200 Å in thickness have been observed by the colloid-SEM method and by the conventional magnetic powder pattern technique. The latter technique, using an optical microscope, gives satisfactory results for recording densities of 5 and 10 kBPI. For high recording densities of 50 and 100 kBPI, clear recorded patterns have been successfully obtained by the colloid-SEM method where dried powder patterns are made under external magnetic fields of 200 to 300 Oe applied vertically to the film planes. It is shown that a better recording can be determined from the obtained patterns, even in high-density recordings. Some discussions are given regarding the relation between the single-domain behaviour of columnar grains in the films and obtained recorded patterns.
Dependence of Lock-in Threshold and Winking Pattern on the Phase-Interaction of Scattering Waves in the Ring Laser
Authors: Kataoka Izumi , Kawahara Yukio
Published: November 2005

Relationships different from previously reported information about the direction of a ring-laser's rotation and winking pattern were observed. Also, the phase difference was observed between the periodic change of the winking intensity and the lock-in threshold when two mirrors are moved while interlocked with a constant optical path length. These phenomena could be satisfactorily explained by introducing the resultant change in the amplitude and the phase of the composite scattered waves from the displacement of the mirrors in self-consistent equations. it was shown that the inequality of the back-scattering rate among the three mirrors and the anisotropy of that to the oppositely directed traveling waves affected the above-mentioned phenomena in an important way.
A Distributed Feedback Evanescent Dye Laser in a Slab-Type Optical Waveguide
Authors: Sugii Masakatsu , Sugihara Okihiro , Ando Masaaki , Sasaki Keisuke
Published: November 2005

Distributed feedback (DFB) oscillation from a thin-film waveguiding evanescent dye laser was observed. Tunable narrow-linewidth oscillations of only the TE0 or TM0 modes were obtained by using a single-mode glass waveguide with a rectangular Rhodamine-6G activated polyurethane film. The experimental results were in good agreement with the results of the theoretical analysis.
Non-Linear Ellipsometer for the Measurement of Coherent and Incoherent Polarization Change in Optically Non-Linear Medium
Authors: Kuwata Makoto , Itagaki Toshikazu , Nagasawa Nobukata
Published: November 2005

A microcomputer-aided ellipsometer with a spinning quarter-wave plate and an analyzer was developed for the simultaneous determination of all the Stokes parameters. This system is quite good for measurements of a photo-induced non-linear polarization change, where a low-repetition pulsed laser is used as the light source. We applied this system for measurements of the photo-induced optical activity associated with the two-photon formation of Γ1 excitonic molecules in CuCl. The coherent polarization change of a linearly polarized probe beam due to two-photon dispersion was clearly observed under irradiation by a circularly polarized excitation beam of 0.5 MW/cm2, and a strong depolarization was found near the two-photon resonance. We ascribe the origin of this depolarization to a random modulation caused by an intensity fluctuation in the pump beam.
A Magnetic Refrigerator for Superfluid Helium Equipped with a Rotating Superconducting Magnet System
Authors: Hakuraku Yoshinori , Ogata Hisanao
Published: November 2005

A rotating magnetic refrigerator based on a new concept has been designed, and a prototype has been tested. The model refrigerator uses gadolinium gallium garnet (GGG) as the working substance and realizes a Carnot cycle between about 2 K and 4.2 K. Heat switches are employed which utilize differences in the heat transfer modes of helium and are free of moving parts. By rotating a system of superconducting coils in the persistent current mode, the working substance at rest is sinusoidally magnetized and demagnetized and this effects the refrigeration cycle. At the maximum magnetic field applied to the GGG of 2.94 T and the operating frequency of 0.20 Hz (rotational speed 4 rpm), the minimum temperature obtained was 1.90 K and the useful cooling power was 1.5 W at 2.10 K.
Generation-Recombination Current in the Emitter-Base Junction of AlGaAs/GaAs HBTs
Authors: Ito Hiroshi
Published: November 2005

The influence of an undoped spacer layer in the emitter-base junction on HBT characteristics was investigated experimentally and theoretically. The ideality factor n of the base current increased from 1.1 to 1.9 for an undoped spacer-layer thickness of between 25 and 150Å. This indicates that the increment of the depletion-layer thickness in GaAs base-side produces a g-r current enhancement in the EB junction. The theoretical analysis also suggests these tendencies. The calculation shows that the n value variation is caused by a one-sided distribution of carriers due to an energy barrier at the heterojunction.
Peroxotungstic Acid Coated Films for Electrochromic Display Devices
Authors: Yamanaka Kazusuke , Oakamoto Hiroshi , Kidou Hirokazu , Kudo Tetsuichi
Published: November 2005

Peroxotungstic acid coated films were investigated for applications to electrochromic display devices. Films coated with peroxotungstic acid aqueous solutions exhibited electrochromism in non-aqueous electrolyte solutions containing Li-salts. A good reversibility for the electrochromic reaction was attained after several writing-erasing cycles involving linear sweeps when the films had been heat-treated at about 120°C for 1 h. Cathodic polarization of the coated films irreversibly reduced the peroxotungstic acid to tungsten trioxide in the electrolyte. This resulted in the devices having poor initial response characteristics. After several aging cycles, however, the coloring efficiency and response rate of the coated films were favorable and comparable to those of tungsten trioxide evaporated films.
Generation of Large Volume Hydrostatic Pressure to 8 GPa for Ultrasonic Studies
Authors: Kozuki Yasushi , Yoneda Akira , Fujimura Akio , Sawamoto Hiroshi , Kumazawa Mineo
Published: November 2005

A new solid-liquid hybrid device has been developed wherein a liquid pressure of 8 GPa can be generated with 150 mm3 in an MA8 high-pressure apparatus. This system was demonstrated by measurements of the velocity of elastic waves in fused quartz; the longitudinal wave had a velocity minimum and an attenuation maximum at 3 GPa.
Temperature Dependence of Molecular Beam Epitaxial Growth Rates for InxGa1-xAs and InxAl1-xAs
Authors: Chika Shigeaki , Kato Hiromu , Nakayama Masaaki , Sano Naokatsu
Published: November 2005

The temperature dependence of the growth and evaporation rates in GaAs, In
x
Ga1-x
As and In
x
Al1-x
As grown by molecular-beam epitaxy (MBE) was measured by reflection high-energy electron-diffraction (RHEED) oscillations. The growth rate and the evaporation rate of GaAs were fitted using a thermodynamical approach. For ternary alloys the calculated results were in agreement with the observed growth rates.
X-Ray Fluorescence Analysis of Hg in SiO2 Films Deposited by Hg-Sensitized Photo-CVD
Authors: Usami Katsuhisa , Mochizuki Yasuhiro , Minagawa Tadashi , Iida Atsuo , Gohshi Yohichi
Published: November 2005

SiO2 films produced by Hg-sensitized photo-CVD were examined using X-ray fluorescence analysis with synchrotron radiation under a grazing incident condition. In all the SiO2 films studied Hg was detected. The concentrations were in the range 60 to 190 ppm. From the glancing-angle dependence of the HgLα intensity, it was concluded that Hg was not localized at the film surface, but was distributed throughout.
Measurement and Analysis of the Atomic Velocity Distribution and the Second-Order Doppler Shift of the Cesium Beam Frequency Standard, NRLM-II
Authors: Ohshima Shin-ichi , Nakadan Yasuhiro , Koga Yasuki
Published: November 2005

The atomic velocity distribution of NRLM-II was measured by the pulse-excitation method and the second-order Doppler shift was estimated (Δf=-4.7±0.3 mHz). The results were consistent with the previous results measured by the truncated Maxwellian method within the experimental errors. An analysis of the experimental errors is also reported.
Thickness Dependence of Etching Rate in Dry Photoetching of Organic Resists
Authors: Ueno Nobuo , Sugita Kazuyuki
Published: November 2005

This paper descrives experimental evidence that the etch rate in the dry photoetching of an organic resist, copolymer of 3,3,4,4,5,5,6,6,6-nonafluorohexyl methacrylate with methyl methacrylate, depends on the initial-film thickness as well as on the exposure time. The results indicate the predominance of a bulk effect over a surface effect during photoetching.
Effects of Deposition Conditions on Properties of a-Si1-xCx:H Diagnosed Using Optical Emission Spectroscopy
Authors: Yoshimoto Masahiro , Aizawa Kouichi , Fuyuki Takashi , Matsunami Hiroyuki
Published: November 2005

The effects of both plasma conditions and substrate temperatures on the properties of a-Si1-x
C
x
:H obtained by a glow-discharge plasma with SiH4-C2H4-H2 were investigated using deposition rates of Si and C atoms and in-situ optical-emission spectroscopy. The deposition rates of Si and C atoms were calculated from the deposition rates of a-Si1-x
C
x
:H (x=0.5-0.99) films with the measured values of the densities of the films. The deposition rate of C atoms is proportional to the emission intensity of CH* from a plasma; this shows that CH* is a good indicator of the decomposition of C2H4. The decomposition of C2H4 is reduced in a C2H4-rich gas composition, which causes a decrease in the deposition rate of C atoms and an increase in the average number of H atoms attached to C atoms in the film. The increase of H atoms in the film provides a low density and a large optical energy gap.
Luminance Distribution of X-ray Image Intensifiers
Authors: Tsuda Motohisa , Kimura Yutaro , Tanaka Shuji
Published: November 2005

For a number of reasons, the luminance distribution of the output image of an X-ray image intensifier (I.I.) tube is not uniform but has a tendency to decrease toward the periphery.
The reasons for this were investigated by measurement and calculation using two types of variable field I.I. with different viewing-field sizes and distances from the focal spot of the X-ray tube to the entrance plane (FED). The most significant cause of the nonuniformity in the luminance distribution is nonuniformity of the local area demagnification ratio (or distortion) of the image and the second is nonuniformity of the local photoelectric sensitivity of the input screen. The nonuniformity of an I.I. can be improved by selecting a smaller viewing field or a larger FED.
The distortion of the image is divided into that from the entrance plane to the input screen and that from the input screen to the output screen, the latter being rather mote significant.
Electron Scattering in GaAs at the Quantum Limit
Authors: Ohyama Tyuzi , Kobori Hiromi , Otsuka Eizo
Published: November 2005

A number of new features of electron quantum transport have been disclosed in the systematic time-resolved cyclotron resonance of GaAs in the far-infrared. The temperature dependence of electron-phonon scattering, magnetic field and concentration dependence of the electron-neutral donor scattering and electron-density dependence of carrier-carrier scattering have been investigated. Available theories give no good relationship with our observations regarding electronphonon type scattering. The electron-neutral donor scattering rate was found to be proportional to the donor concentration and the inverse square root of the magnetic field, the magnitude being much lower than predicted by the Erginsoy relation. The carrier-carrier scattering rate has been the only thing comparable with the existing theoretical predictions.