bluuebunny/crossref_metadata_2025 huggingface dataset:
VUV-Assisted Etching of Silicon (100) and Poly(methyl methacrylate)
Authors: Ueno Nobuo , Mitsuhata Tsuneo , Sugita Kazuyuki , Tanaka Kenichiro
Published: February 2005

The possibility of photoetching of silicon and poly(methyl methacrylate) (PMMA) has been studied using vacuum ultraviolet (VUV) light under the existence of reactive species produced by 2.45 GHz discharge of CF4/O2(5%) gas. The VUV light was obtained by hydrogen gas discharge with a capillary-type discharge lamp. For both materials, the chemical dry etching by the reactive species was clearly enhanced by VUV irradiation to the surface of the materials. The results suggest that the VUV-induced etching is the result of a surface photochemical reaction which is useful in producing anisotropic photoetching.
A Hybrid Fitting Method for Multiplet of K X-Ray
Authors: Hiromura Kazuyuki , Okada Eiji
Published: February 2005

A new fitting method is presented for analysis of K X-ray multiplets including very close-lying peaks. The method is composed of two routines. First, we fitted the second derivatives of a mathematical model for peaks to the data transformed by a second differentiation filter associated with Stirling's interpolation formula, then determined the profile parameters (width and centroid) of a peak by a nonlinear least-squares method. Second, we fitted the profile to raw data to evaluate areas of component peaks by a linear least-squares method, keeping the profile parameters constant This analysis method, named the “hybrid method”, was applied to the analysis of the K X-ray spectra of As, Ag and Eu and is shown to be more reliable and effective for unravelling multiplets than conventional methods.
Polarized Near-Band Edge Photoluminescence in CuGaS2 Single Crystal
Authors: Shirakata Sho , Murakami Kazuo , Isomura Shigehiro
Published: February 2005

Near-band edge photoluminescence in CuGaS2 has been measured at room temperature. It has been found that the green emission at 2.454 eV is strongly polarized parallel to the c-axis. In addition, a new emission peaked at 2.55 eV has been observed with the polarization perpendicular to the c-axis. These emissions are discussed in terms of the optical selection rule and exciton energies.
Persistent Photoconductivity in Doping-Modulated a-Si:H Multilayers
Authors: Ito Hiroshi , Kikuchi Minoru
Published: February 2005

Effects of high temperature illumination and annealing on persistent photoconductivity (PPC) were investigated in doping-modulated hydrogenated amorphous silicon nipi-multilayers. Room temperature illumination followed by annealing at 385 K resulted in room temperature conductivity considerably reduced from that of an unexposed sample. High temperature (357 K) illumination caused no PPC, but after annealing at 385 K, we observed room temperature conductivity much reduced from that of the unexposed sample. Further, this sample showed PPC critically dependent on the exposure level when illuminated again at room temperature. The PPC-resistive nature induced by high temperature illumination is explained in terms of the Staebler-Wronski (S-W) effect, demonstrating the interplay between the PPC and the S-W effect. Decay kinetics of the PPC is also briefly discussed.
ESR in Diamond Thin Films Synthesized by Microwave Plasma Chemical Vapor Deposition
Authors: Watanabe Ichiro , Sugata Ken
Published: February 2005

A variety of diamond films of poor and good quality are synthesized by microwave plasma CVD from a mixture of hydrogen and CH4, CH3OH or C2H5OH. A comparative study on the ESR and Raman spectra of these films is performed. The diamond films of good quality have a spin density of ∼1018 cm-3. The peak-to-peak linewidth in the ESR signal varies from 6.1 G in the film of poor quality to 3.0 G in the film of good quality. This change can be used as a convenient method for evaluating the quality of diamond films.
The Range of Observable Depth in a pnp Si Darlington Tr-Chip by Electron-Acoustic Microscopy
Authors: Takenoshita Hiroshi
Published: February 2005

Using a pnp Si Darlington Tr-chip as a specimen, images of electron-acoustic microscopy (EAM) and several modes of SEM images were observed in situ within the same area. The EAM was operated at a blanking frequency of 1 MHz and a duty ratio of 50%. In the EAM mode, the p-n junction, which was short-circuited to an Al electrode (∼3 µm) on the surface, was identified at HV ≧25 kV. In the SEM mode, however, it was observed only as surface irregularity. The results were as follows: (1) the contrast of the EAM image varied with the bias condition, (2) the observable depth in EAM was related to the electron range, and (3) the depth corresponded to approximately 60% of the electron range. The results agreed with those previously reported using npn-type Tr-chips. A mechanism of acoustic signal generation is also discussed in this paper.
Low Field Transport Properties of Two-Dimensional Electron Gas in Selectively Doped N-AlGaAs/GaInAs/GaAs Pseudomorphic Structures
Authors: Luo Ji-Kui , Ohno Hideo , Matsuzaki Kinichiro , Hasegawa Hideki
Published: February 2005

In order to clarify the low field transport properties of two-dimensional electron gas (2DEG) in selectively doped (SD) AlGaAs/GaInAs/GaAs pseudomorphic structures, electron effective mass as well as electron scattering mechanisms were investigated using molecular beam epitaxially grown SD-Al0.3Ga0.7As/Ga0.87In0.13As/GaAs structures. Temperature dependence of Shubnikov-de Haas oscillation showed that the effective mass of 2DEG was greater than that of a bulk alloy. Enhancement of the effective mass quantitatively agrees with that expected from the effect of strain and nonparabolicity. The 2DEG mobilities were measured by Hall measurements as a function of carrier concentration, n

s
, as well as a function of temperature. At a low temperature range (< 40 K), mobility increased with increasing n

s
and saturated at a high n

s
region where virtually no temperature dependence was observed. Comparison of the mobility with that of AlGaAs/GaAs heterostructures and the results of the scattering theory revealed that the mobility at low temperatures can be quantitatively explained by the cluster scattering due to compositional nonuniformity in addition to the remote ionized impurity scattering.
Optical Quenching of the Extrinsic Light Induced Enhanced Photocurrent in Semi-Insulating GaAs
Authors: Jimenez J. , Alvarez A. , Gonzalez M. A. , Bonnafé J. , Saja J. A. de
Published: February 2005

The existence of an optically enhanced photocurrent was demonstrated to be associated with the creation of a metastable state in previous papers. Herein the optical recovery of the normal state is studied. A partial restoration of the initial situation (low photocurrent level) is obtained after illumination with photons of the AsGa
+ EPR signal quenching spectral range. The recovery is made throughout the valence band, as revealed by photoHall experiments. All that suggests that the AsGa defect is involved in the optically enhanced photocurrent effect.
Separation and Characterization of Superconducting YBa2Cu3O7-x Powder
Authors: Hayashi Koya , Yokota Yasuhiro , Morita Shuji , Hanada Noriaki , Hayashi Shin-ichiro
Published: February 2005

The superconducting YBa2Cu3O7-x
powder has been sorted using the Meissner effect. Two separation methods have been employed. One is separating the powder at a constant temperature, the other is separating it over a temperature gradient. Both methods are effective for separating the high-T
c superconducting powder from the low-T
c superconducting parts. Separated powder was examined by X-ray diffraction and quantitatively analyzed by EPMA as well as by chemical analysis, and by a TEM. The higher-T
c part of YBa2Cu3O7-x
powder was characterized by smaller lattice constants, higher oxygen concentration, and higher twin density. The low-T
c YBa2Cu3O7-x
sample shows a low Cu/Y ratio relative to the high-T
c sample.
Experimental Study of Noise Characteristics of Large-β dc SQUID with Resistively Shunted Inductance
Authors: Kohjiro Satoshi , Enpuku Keiji , Yoshida Keiji , Yamafuji Kaoru
Published: February 2005

Noise characteristics of dc SQUIDs in large β regimes have been studied experimentally in the case when a SQUID inductance is resistively shunted. Here, β=2L
I
0/Φ0 is the modulation parameter, L is the SQUID inductance, I
0 is the critical current of the Josephson junction and Φ0 is the flux quantum. It is shown experimentally that the performance of the SQUID does not degrade significantly even for large β values; for example, the minimum energy resolution of the SQUID is as small as ε=25h and the flux region where ε<50h is as wide as 0.1Φ0, even for the case β=12, where h is the Planck constant. The experimental results agree quantitatively with the theoretical ones.
Fundamental Characteristics of a New Superconducting Motor Called the “Meissner Motor”
Authors: Takeoka Akio , Ishikawa Akira , Suzuki Masaharu , Kishi Yasuo , Kuwano Yukinori
Published: February 2005

We developed a brand new superconducting motor using high-T
c ceramic superconductors for the first time. This motor, called the “Meissner Motor”, utilizes the repulsive force caused by the Meissner effect, which appears below T
c and disappears above that. The motor rotated at a maximum speed of 40 rpm. Though the repulsive force to drive the motor increased with a decrease in temperature or an increase in the gradient magnetic field, it was only about 1.1 gf/g at 77 K in 3500 G/cm. This motor would have a maximum torque of 5.0 gf-cm theoretically, but actually had a torque of about 0.66 gf-cm, because it took some time to be cooled below T
c. Furthermore, the shortage of heating power was found to limit the rotating speed of the motor.
The Structure of Co–Cr Films Sputtered onto a Moving Substrate
Authors: Tomie Takashi , Ogasawara Makoto , Kato Yukio , Ouchi Isuke
Published: February 2005

Transmission electron micrographs, microbeam electron diffraction and X-ray pole figures were employed in order to elucidate the structure of Co–Cr films formed by facing targets sputtering. The c-axes of the hcp structure of the microcrystallites deposited on a static polyethylene terephthalate substrate had a sharp distribution around the normal of the film plane at the center of the deposition area, but were inclined slightly at the edge with respect to the target configuration. For a Co–Cr permalloy double-layered film formed on a moving substrate, the c-axes of individual crystallites scattered considerably, although the average was maintained along the normal of the film plane, with a slight tilt toward the forward-moving direction.
Average Lengths and Statistics of Bonds in In1-xGaxAs1-yPy Quaternary Alloy Semiconductor
Authors: Ichimura Masaya , Sasaki Akio
Published: February 2005

Statistics of relative numbers of bonds are derived by a thermodynamic analysis for the InGaAsP quaternary alloy semiconductor. Strain energy is taken into account as a dominant portion of the mixing enthalpy. In calculating the strain energy, a given kind of bond is considered to have various amounts of strain because of the randomness in the atom arrangement. On the basis of the results from the thermodynamic analysis, the average bond lengths in InGaAsP are obtained. Their dependences on the statistics of bonds and on the composition are discussed. The calculated bond lengths agree fairly well with those obtained by the extended-X-ray-absorption fine-structure measurement.
A Pseudopotential Approach to Mixing Enthalpies of (III–V)1-x(IV2)x
Authors: Ito Tomonori
Published: February 2005

The mixing enthalpies of pseudobinary (III-V)1-x
(IV2)
x
solid solutions are investigated using a pseudopotential perturbation approach. These enthalpies and lattice parameters of (III-V)1-x
(IV2)
x
with ordered (zincblende) and metastable disordered (diamond) structures are successfully calculated by accounting for atomic configurations. The lattice parameters are congruent with Vegard's law and the mixing enthalpies of the ordered structure alloys are found to be larger than those of the disordered structure alloys. The disordered alloy systems with small lattice parameter mismatch such as (GaAs)1-x
(Ge2)
x
and (GaP)1-x
(Ge2)
x
have a miscible region over the entire concentration range at very low temperatures. Those calculated results are also compared with Hume-Rothery's empirical rule.
AC Discharge Characteristics of a Needle-to-Semicircular-Electrode Gap with Solid Dielectric Surface under High Humidity
Authors: Hasegawa Seiichi , Akagami Hideo
Published: February 2005

In this study, the discharge phenomena combined with the air and the creepage discharges have been discussed experimentally with a simplified model electrode gap. A conventional frosted glass plate was used as the solid dielectric. As a result, some noticeable phenomena have been found. The flashover voltages on the solid surface depend upon the relative humidity in air and decrease with increasing humidity. Especially, when the vertical gap length (or the height) is given to the needle electrode to increase the flashover voltages, the flashover voltages in high humidity seem to be free from the vertical gap length of the needle electrode, in which the inclined angle formed with the horizontal gap length and the vertical gap length is less than 30°.
Growth of PbSe and PbTe Ultrafine Particles by Gas Evaporation Method
Authors: Kaito Chihiro , Saito Yoshio , Fujita Kazuo
Published: February 2005

Ultrafine particles of lead selenide and telluride have been produced by the reaction of the metal and selenium or tellurium vapors. It is shown that the crystal habits of the grown crystals are determined by the crystal structure type.
Photoemission Study of PbIn Alloy Surface Segregation Using Synchrotron Radiation
Authors: Suzuki Mineharu
Published: February 2005

PbIn alloy surfaces were examined using photoemission spectroscopy with synchrotron radiation. Pb segregation was revealed in the surface subnanometer region. Pb concentration at the surface was observed to be higher by about 20 at.% than that of bulk for indium 38 at.% alloy.
Nonlinear Dielectric Relaxations in a Vinylidene Cyanide / Vinyl Acetate Copolymer
Authors: Furukawa Takeo , Tada Masahiro , Nakajima Kenji , Seo Iwao
Published: February 2005

The third-order nonlinear permittivity has been measured as a function of the frequency for an alternate copolymer of vinylidene cyanide and vinyl acetate at temperatures above T
g
∼170degC. The observed frequency spectra were found to be fitted by a function Δε3/(1+(i ωτ3)β3
)3 with negative Δε3. Its real part changes sign from positive to negative with decreasing frequency. A negative Δε3 implies that the polarization tends to be saturated as the field is increased. Combined knowledge about linear and nonlinear dielectric increments allows an estimate of the size of equivalent dipoles, which explains the unusually large permittivity of this copolymer.
Particular RF Property in a Magnetized Plasma near the Lower Hybrid Frequency
Authors: Ohnuma Toshiro
Published: February 2005

Particular RF properties, that is, potential fields radiated from a localized source, in a magnetized plasma are investigated numerically near the lower hybrid frequency. The coupled stationary field patterns of the lower hybrid wave and the ion acoustic wave are obtained.
Microcomputer-Assisted CCD Driver System for General Use
Authors: Mizukata Katsuya , Tsunemi Hiroshi
Published: February 2005

We report here a CCD driver system which can operate almost any type of CCD in any type of operation mode. Since all the required clock patterns can be generated with the software, we can easily modify the clock pattern. Using this system and the frame transfer-type CCD, we obtained an X-ray image of 8.9×11.8 mm2 in the full frame imager mode with a spatial resolution of one pixel size (11.5×27 µm2).
Phosphorus Doping Properties of Hydrogenated Amorphous Silicon Prepared by Mercury Sensitized Photo-CVD
Authors: Suzuki Kazuhiko , Kuroiwa Koichi , Tarui Yasuo
Published: February 2005

A doping-induced defect creation of phosphorus-doped mercury-sensitized photo-CVD amorphous silicon is investigated by photoluminescence and the isothermal capacitance transient spectroscopy technique. Two kinds of silicon dangling bonds, i.e., the isolated dangling bond and the dangling bond coupled with a charged dopant have been observed. Their concentration dependence on the gas-phase doping ratio is different from those reported for glow discharge a-Si:H films. The isolated one increases as a square root of the gas-phase doping ratio, while the coupled dangling bond shows linear dependence on the ratio. A possible origin of the difference is discussed in terms of surface reaction.
Texture Morphology of SnO2:F Films and Cell Reflectance
Authors: Mizuhashi Mamoru , Gotoh Yoshio , Adachi Kunihiko
Published: February 2005

The texture formation on the surface of SnO2:F films was carried out using a four component CVD reaction system with tin tetrachloride as a main source. The texture up to about 30% in terms of the haze value could be formed by selecting CVD parameters. It was found in the transmission measurement of hazy SnO2:F films that a part of incident light escaped from the cut edges of the glass substrate even if the integration sphere was used. A nondestructive immersion method is proposed. This enables more exact evaluation of light quantity effectively transmitted to the active part of the a-Si solar cell when it is combined with the reflectance measurement of a pseudocell. It was also found that the reflectance of pseudocells decreased as the haze value increased, and as the shape of grains became sharper when the haze values were similar.
A Novel Real-Time Chirp Measurement Method for Ultrashort Optical Pulses
Authors: Mogi Kazuo , Naganuma Kazunori , Yamada Hajime
Published: February 2005

Rapid measurements of ultrashort optical pulse chirping were realized with a newly developed real-time chirp monitor. The application of a moving coil translator and electrical filters enabled the rapid measurement and decoding of fringe-resolved second-harmonic-generation (FRSHG) autocorrelation. The prototype system displayed chirping characteristics at a repetition rate higher than a few hertz, which demonstrates the usefulness of this monitor for dye laser system alignment.
Second Harmonic Generation in Crystals of Benzofurazan Derivatives
Authors: Kurihara Takashi , Kaino Toshikuni , Matsumoto Shiro , Tomaru Satoru
Published: February 2005

A discussion is presented on the second harmonic generation of benzofurazan (benzo-2-oxa-1,3-diazole) derivatives. In particular, a report is made on the phase-matched second harmonic generation of a nonlinear optical material, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl).
Aspects of the Defect Reactions Related to Carbon Impurity in Silicon
Authors: Londos C. A.
Published: February 2005

Deep-level transient spectroscopy (DLTS) measurements are reported for the well-studied carbon (C) and oxygen (O) related centers with activation energy aroundEv+ 0.36 eV irradiated p-Si. Comparisons of the concentrations of this defect state with those of carbon interstitial (Ci) defect state in pulled and float-zone material have been considered. The results yield some new insight concerning the Ciinvolvement in reactions with primary defects and other impurities a) during and after low-temperature irradiation and b) after annealing around room temperature.
Band-Gap Energy Anomaly and Sublattice Ordering in GaInP and AlGaInP Grown by Metalorganic Vapor Phase Epitaxy
Authors: Suzuki Tohru , Gomyo Akiko , Iijima Sumio , Kobayashi Kenichi , Kawata Seiji , Hino Isao , Yuasa Tonao
Published: February 2005

The previously reported photoluminescence(PL)-peak-energy anomaly problem for Ga0.5In0.5P grown on GaAs by metalorganic vapor phase epitaxy (MOVPE) was studied in detail. X-ray microprobe analysis, and optical transmission spectra measurements were carried out to examine alloy compositions and band-gap energies (E
gs), respectively. The MOVPE growth condition dependence of {1/2, 1/2, 1/2} superlattices (SLs) on the cation sublattice in Ga0.5In0.5P was studied in detail, using transmission electron microscopy. The correlation between the E
g anomaly and the SLs was examined in detail and established. Raman spectra seemed to show zone-folding effects due to the monolayer SL. A similar E
g anomaly was reported for AlGaInP. AlGaInP and AlInP were also found to show the same SLs.
Excitation of Azimuthally Propagating Ion-Cyclotron Drift Waves in Large Magnetized Plasma
Authors: Kando Masashi , Kishimoto Shigeru , Sugai Hideo , Ikezawa Shunjiro
Published: February 2005

The dispersion relations of ion-cyclotron drift waves strongly depend on both the axial and azimuthal wave numbers as well as the radial gradient of the plasma density. The dispersion surfaces of the waves have been shown graphically in order to determine the characteristics of ion-cyclotron drift waves. The azimuthally propagating electrostatic waves have been excited externally by a mesh grid in a large-diameter magnetoplasma. The measured azimuthal dispersion relations agree with the theoretical ones of ion-cyclotron drift waves.
Conversion Efficiency of a Large-β DC-SQUID with a Resistively Shunted Inductance
Authors: Kohjiro Satoshi , Enpuku Keiji , Yoshida Keiji , Yamafuji Kaoru
Published: February 2005

The conversion efficiency between a signal magnetic flux and the output power of a large-β dc SQUID, i.e., a SQUID with a modulation parameter β larger than unity, have been studied theoretically. In our investigation the inductance of the SQUID was shunted by using a damping resistor. The dependence of the output power on such SQUID parameters as β, the McCumber parameter βc and the damping parameter γ=R

s
/R

d
(R

s
and R

d
are the shunt and the damping resistances, respectively) was investigated in detail. It has been shown that an order-of-magnitude increase in the output power can be realized with a large-β SQUID without a degradation of noise characteristics, compared with the case of β=1. It has also been shown that the values of βc=0.4 and γ=1 are optimum with regard to a large output power and a low-noise operation of the SQUID.
Bunch Lengthening in Single-Bunch Mode of UVSOR Storage Ring
Authors: Yonehara Hiroto , Kasuga Toshio , Hasumoto Masami , Kinoshita Toshio
Published: February 2005

The bunch lengthening and widening in the single-bunch mode of the UVSOR electron storage ring were measured. Certain thresholds were observed in the measurement and they were consistent with the thresholds determined by the balance between the bunch lengthening due to the distortion of the acceleration potential well and the microwave instability. The longitudinal coupling impedance of the UVSOR ring was obtained with the threshold current. The horizontal bunch widening of the beam was also observed above the threshold current.
Cylindrical Mirror Analyzer (CMA) with an Axially Integrated ISS-AES Gun for Surface Composition Analysis
Authors: Katayama Itsuo , Shoji Fumiya , Oura Kenjiro , Hanawa Teruo
Published: February 2005

We have devised CMA with an axially integrated ion-electron gun for low-energy ion scattering spectroscopy (ISS) and Auger electron spectroscopy (AES). This allows an alternate analysis of ISS and AES within 30 sec, being applicable to surface segregation phenomena. The CMA accepts a large segment of the particles scattered through an angle of 146° at normal incidence. The detection sensitivity and the mass resolution in the ISS mode are shown using Ne+ ion beams with an energy of 1 keV. The Ne+ ion dose required to scan a scattering peak can be reduced to an order of 1011 ions/cm2. A practical application is presented for the coevaporated Cu-Mu alloy films prepared in an ultrahigh vacuum.
Microwave Behaviour of Bi2O3, TiO2 and γ-Fe2O3 Thick Film Overlays on Microstrip Rejection Filter
Authors: Joshi A. M. , Mandhre M. M. , Jadhav M. L. , Gangal S. A. , Karekar R. N.
Published: February 2005

The paper reports the preliminary studies on the effect of thick film overlays of Bi2O3, TiO2 and γ-Fe2O3 materials on microstrip rejection filters. Variation of resonant frequency and quality factor of the rejection filter with overlay thickness are studied. It is observed that resonant rejection frequency and quality factor decrease smoothly with increase in the overlay thickness for Bi2O3 & TiO2 with logarithmic relation; but for γ-Fe2O3 after a particular thickness, resonant rejection abruptly disappears and its variation is slightly orientation dependent.
X-Ray Study on Single Crystals of Hg1-xMnxTe
Authors: Chan B. T. , Fun H. K. , Teoh S. G.
Published: February 2005

Various samples of Hg1-x
Mn
x
Te with x=0, 0.0001, 0.0025 and 0.1 were investigated for the relative shifts of the atoms in the unit cell using the X-ray single-crystal technique. It was found that the lattice constants, on the average, decrease with increasing x as Mn dopants entered by random substituton into the unit cell.
Optical Isolator for Orthogonally Polarized Two-Frequency Laser
Authors: Umeda Norihiro , Eguchi Tadashi
Published: February 2005

An optical isolator for an orthogonally polarized two-frequency laser was investigated experimentally. It consisted of two polarization beam splitters, a Faraday rotator and a half-wave plate. The experiment showed isolation ratios of 23.5 dB and 26.9 dB for the orthogonally polarized components. We demonstrated that a laser source was insensitive to the feedback light from the external optical system using our optical isolator.
Phased-Array Laser Diode with Buried Optical Guides and Inverted Current Injection
Authors: Zucker Erik P. , Hashimoto Akihiro , Fukunaga Toshiaki , Watanabe Nozomu
Published: February 2005

A novel, phase-locked semiconductor laser diode array design is presented that utilizes current injection through the spacer regions between the waveguides to obtain fundamental supermode oscillation. The real-index waveguide array fabricated by selective disordering of multiquantum well optical guide layer, spatially removed from the active layer, is proposed.
Recovery Enhancement of hFE Due to Pulse Aging for Electron-Irradiated npn Si Transistors
Authors: Ohyama Hidenori , Nemoto Kuniharu
Published: February 2005

The differences in h
FE recovery properties between thermally annealed and pulse-aged npn Si transistors, which were irradiated with 2 MeV electrons to a fluence of 1015 e/cm2, were investigated for the first time. The recovery of h
FE after pulse aging was found to be enhanced in comparison with that after thermal annealing. This recovery enhancement was increased by increasing the collector peak current and the collector-base reverse voltage.
Position Determination by Laser Marks of Biological Samples Placed on a Plastic Track Detector and Inactivation of B.subtilis Spores by a Single Heavy Ion
Authors: Takahashi Tan , Yatagai Fumio , Katayama Toshiko , Konno Satoshi , Nakano Kazushiro , Kaneko Ichiro , Kasuya Takahiro
Published: February 2005

Reference grid marks were printed with a UV laser beam on a dyed CR-39 track detector. By using the marks, inactivation probability of the spores on the plastic detector was obtained as a function of distance from the path of a single heavy ion.
Lattice Defects in High-Dose As Implantation into Localized Si Area
Authors: Tamura Masao , Horiuchi Masatada
Published: February 2005

Cross-sectional transmission electron microscopy observations have been carried out to clarify two-dimensional depth distributions of lattice defects generated in high-dose (5×1015 and 2×1016 ions/cm2), 80 and 150 keV As-implanted, and annealed Si through 1.0 and 1.5 µm windows on (100) Si. Amorphous Si (a-Si) layer thicknesses formed by implantation range between projected range, R
p, +(5∼6) standards deviation, ΔR
p, with a lateral spread of about 0.18 times a-Si thickness under the mask edge. Typical post-annealed, induced defects in such amorphous layers are mask edge defects composed of dislocation lines caused by a complicated process for recovering mask edge amorphous layers, together with commonly observed dislocation loops in high-dose As implantation. Interaction between dislocation loops and knocked-on oxygen atoms is discussed, particularly concerning the elimination or survival of As-rich precipitate-induced dislocation loops.
An X-Ray Diffraction Study of Martensitic Transformation in Ti-Doped Nb3Sn
Authors: Watanabe Yousuke , Toyota Naoki , Inoue Tetsuo , Komatsu Hiroshi , Iwasaki Hiroshi
Published: February 2005

The effect of titanium addition on the martensitic transformation in Nb3Sn was investigated by low-temperature X-ray diffraction using small-sized (0.1–0.3 mm) high-quality single crystals. It has been found that addition of 0.2 at.% Ti lowers the transformation temperature, T
m, by 3 K while further addition up to 1.5 at.% suppresses the transformation. T
m is very sensitive to the manner of sample adhesion to the cold end of the cryostat and it rises nearly to ambient temperature if improperly adhered. The axial ratio a/c of the 0.2 at.% Ti doped alloy was measured to be 1.001 at 30 K, which compares to a value of 1.005 for the undoped alloy. A tendency to form a single tetragonal domain with decreasing temperature through T
m for the 0.2 at.% Ti doped alloy was observed.
Measurements of Work Function Change of Fe(110) Surface due to Adsorption of Carbon Monoxide
Authors: Ueda Kazuyuki , Mega Tetsuya
Published: February 2005

Changes in the work function of the surface of single-crystal Fe(110) due to carbon-monoxide (CO) adsorption have been studied as a function of CO exposure. The work function increased by 0.425 eV for Fe surface covered with saturated CO. The changes in the work function originating from different adsorbed states of CO are discussed in conjunction with the thermal desorption spectroscopy (TDS) and Auger analysis.
Fracture of GaAs Wafers
Authors: Yasutake Kiyoshi , Konishi Yoshito , Adachi Kaoru , Yoshii Kumayasu , Umeno Masataka , Kawabe Hideaki
Published: February 2005

Fracture characteristics of undoped and several kinds of doped GaAs single-crystal wafer were studied. The fracture toughness value determined by four-point bending fracture test of specimens precracked by indentation at room temperature showed no difference for In-, Si-, Cr- and undoped crystals. Indentation microcracking characteristics of In-, Si- and undoped crystals and probability distribution functions of the fracture stresses of In-doped and undoped crystals were found not to have meaningful differences. The polarity of the indentation cracking in relation to the indentation rosette extension and the temperature dependence of the fracture toughness value in relation to the crack tip plasticity were also investigated.
Temperature Dependence of PHB Hole Profiles in Polymer Matrices
Authors: Nishi Toshihiro , Arishima Koichi , Tabei Hisao , Hiratuka Hiroaki
Published: February 2005

The temperature dependences of irreversible hole decay for tetraphenylporphines / polymers as guest / host systems were investigated. The irreversible hole decay values depend on the chemical structure of matrix polymers. Irreversible hole decay is caused by the motion of polymer side chains or backbones of poly(alkyl methacrylate)s and polyethylene. Excellent hole retention is observed in the PMMA matrix, and is explained by the small, symmetrical structure of methyl groups. PnDMA shows hole decay profiles similar to those of PE. This result indicates that PnDMA forms microstructures that are similar to PE microstructures because of long methylene side chains.
A Study of the Magnetic Domains of Isolated Fine Particles of Ba Ferrite
Authors: Kitakami Osamu , Goto Kimiyoshi , Sakurai Tomoaki
Published: February 2005

Isolated Ba ferrite particles are prepared by the conventional powder metallurgical method, and the magnetic domains of about 200 particles 0.5 to 5 µm in size are investigated by the colloid-SEM method (the Bitter method using a scanning electron microscope). The relationship between the three-dimensional sizes of Ba ferrite particles and their magnetic domain states is clarified. It is found that the critical size of isolated single-domain particles of Ba ferrite is somewhat larger than the value calculated using the magnetic domain theory.
Undoped Semi-Insulating GaAs of Very Low Residual Acceptor Concentration
Authors: Reichlmaier S. , Löhnert K. , Baumgartner M.
Published: February 2005

We have studied undoped GaAs of shallow acceptor concentrations close to and below 5·1014cm-3. After ingot annealing with slow cooling rate this material shows resistivity values below 107 Ωcm, spanning several orders of magnitude. By an additional annealing procedure these values can be raised to some 107 Ωcm. DLTS results are presented indicating that the electrical characteristics in the ingot annealed state are governed by uncompensated deep donors shallower than EL2, mainly EL6 near E
c -0.35 eV. After the additional annealing a drastic decrease in EL6 concentration is observed, which explains the rise in resistivity. This is confirmed by theoretical calculation of the resistivity in dependence of the EL2 and EL6 to net acceptor compensation ratio, which agrees quantitatively with the experimental values.
Seed-Atom Density Profiles in a Boundary Layer on a Flat Plate in MHD Combustion Gas Plasmas
Authors: Ikegami Tomoaki , Matsuo Takahide , Oniki Kazunori , Masuda Mitsuharu , Watanabe Yukio , Akazaki Masanori
Published: February 2005

Density profiles of potassium (K) were measured experimentally in a boundary layer on a cooled metal flat plate, and the K density was found to be higher than the estimated value without chemical reactions. Results of the boundary layer simulation with reactions and transport of chemical species showed that this enrichment of the K density was caused when the chemical species densities largely deviated from their thermochemical equilibrium values. The simulation also showed that this phenomenon might appear in a viscous sublayer in a turbulent boundary layer of an actual MHD power generation channel.
Spectroscopic Studies on Carbon Coating in Heliotron E
Authors: Kondo Katsumi , Okazaki Kiyohiko , Oda Toshiatsu , Noda Nobuaki , Akaishi Kenya , Kaneko Hiroshi , Mizuuchi Tohru , Sano Fumimichi , Motojima Osamu , Iiyoshi Atsuo
Published: February 2005

Visible and vacuum ultraviolet (VUV) spectroscopic studies on carbon coating were described. In Heliotron E, carbon coating was performed on the vacuum chamber wall to reduce metallic impurities. The carbon layer was deposited on the wall using glow discharge with CH4 and H2 mixed gases. The CH(A
2Δ-X
2Π) spectrum was observed in the CH4+H2 glow discharge, and its excitation mechanism was discussed in relation to H2 and Hα emissions. The reduction of iron impurity by the carbon coating was confirmed measuring multiply ionized iron emissions by a calibrated VUV monochromator in the neutral beam heated plasmas. The behavior of the retained hydrogen, which was absorbed in the carbon layer during the glow discharge, was also studied observing Hα and Dα emissions in the RF-heated plasmas by the ion cyclotron range of frequency (ICRF).
Theory of Photoacoustic Measurements of the Thermal Diffusivity of Two-Layer Samples
Authors: Tominaga Tetsuo , Ito Kenichi
Published: February 2005

The theory of photoacoustic measurements of thermal diffusivity making use of rear-surface illumination has been extended to include the effect of two-layer samples. It has been found that the ratio of the thermal thickness of each layer becomes important in measuring the phase shift of photoacoustic signals. When the thermal thickness of one layer is thicker than another layer, only the thermal diffusivity of the thermally thicker layer could be obtained. On the other hand, when the thermal thickness of both layers are the same order, the combined thermal diffusivity of the two-layer system is obtained.
Free Vibrations of a Drop in Partial Contact with a Circular Support
Authors: Watanabe Yoshio
Published: February 2005

Axisymmetric free vibration of a drop in partial contact with a circular solid support is analysed under the conditions of zero gravity and negligible viscous effects. It is assumed that the axial gradient of pressure is uniform everywhere in the vibrating drop and the lowest eigenmode is obtained. The theoretical results for different radii of the support are compared with the computed results of Sterni and Sabetta and also with the experimental results of Bisch, Lasek and Rodot.
Time-of-Flight Measurement of Particles in SiO2 Sputtering
Authors: Tominaga Kikuo , Kume Michiya , Tada Osamu
Published: February 2005

The decrease of the deposition rate of SiO2 sputtered films is investigated by using time-of-flight apparatus. It is found that the increase of signal intensity of H atoms corresponds to the decrease of the deposition rate of SiO2 films, which confirms the reports by Hosokawa that the absorbed H2O at the target surface is the most important factor affecting the decrease of the deposition rate of SiO2 films.
New Plasma Oxidation of InP for IGFET
Authors: S.N. Al-Refaie S.N. Al-Refaie
Published: February 2005

InP surfaces have been oxidized by reactive sputtering of InP target in a magnetically confined, DC excited, plasma of pure oxygen. Microprobe and Auger analyses have indicated a uniform composition with equal proportions of phosphorus and indium oxides. Measurements on MOS devices have shown a film resistivity of 4.6 ×1013 Ω·cm and minimum interface states density of 1.2 ×1012/cm2/eV. The MOSFET on p-InP has indicated an electron mobility of 400 cm2/Vs in the induced n-channel.
Doping Effect in Solution of Poly(3-Alkylthiophene)
Authors: Gu Hal Bon , Nakajima Shigeaki , Sugimoto Ryu-ichi , Yoshino Katsumi
Published: February 2005

Poly(3-alkylthiophene) in solution can be doped just as in the case of polythiophene films, resulting in the suppression of the interband absorption and the appearance of absorption peaks in the infrared region originating in the transitions between polaron states and from the valence band to the low-lying polaron state. Enhancement of the spin density by doping in an ESR measurement was also observed, which supports the polaron formation but not bipolaron formation. From these results, it has been clearly demonstrated that even a single polymer chain has the characteristics of conducting polymers.
Random-Dot Model in the Presence of Signal
Authors: Yamada Isao , Tanaka Kazuo
Published: February 2005

A random-dot model which can contain signal information is presented. A two-dimensional nonstationary Poisson process was applied to the conventional random-dot model in order to construct the new model. The exact forms of the average transmittance and the transmittance autocorrelation function were obtained. An application of the new model to the evaluation of the detectability of radioisotope images is demonstrated by showing numerical calculations. The model proposed in this paper can be applied to image noise analysis, such as signal-to-noise prediction of photographic images and radioisotope images in gamma-ray imaging systems.
Evaluation of MQW Wafer for Surface-Emitting Laser by X-Ray Diffraction
Authors: Onda Haruka , Uenohara Hiroyuki , Koyama Fumio , Iga Kenichi
Published: February 2005

Wide-angle double-crystal X-ray diffraction was utilized to characterize a multi-quantum well (MQW) structure designed for a surface-emitting MQW laser. A precise measurement of the period was achieved and an evaluation of the abruptness of a hetero-interface is presented.
Measurements of Lattice Parameters and Half-Widths of the Rocking Curve on GaAs Crystal by the X-Ray Double-Crystal Method Using a Cu Kα Doublet
Authors: Fukumori Taichiro , Futagami Kōji
Published: February 2005

GaAs wafers grown by HB and LEC techniques were appraised by the double-crystal method using a Cu Kα doublet. Distributions of lattice strains and defect density along the <110> radial direction on wafers have been obtained from measurements of lattice parameters and half-widths of the rocking curve, respectively.
A Note on the Cross Section of the Syummetric Charge Transfer between Uranium Ions
Authors: Mizushima Masataka
Published: February 2005

The time development operator formalism is presented in order to justify the conventional formulas for the cross section of the symmetric charge transfer process. The formulation clarifies the approximations made in the derivation. The cross section for the process U+U
+→U
+
U is examined. Considering the situation that the lower energy states of the uranium atom/ion are made of two kinds of cores, 5f3(4I) and 5f3(2H), with an energy difference of less than 0.1 eV, and that transfer of one of the 7s-electrons contributes to the cross section of charge transfer to about the same extent as that of the 6d-electron, we obtain a theoretical result which agrees with a recent experimental value at 100 eV.
Flux Reversal and Calculations of Hysteresis Loops in CoCr Sputtered Films
Authors: Honda Shigeo , Yamakawa Toshiaki , Takahashi Kenichi , Kusuda Tetsuzo
Published: February 2005

Stripe domain patterns were clearly observed in CoCr-sputtered films using the Bitter method. These patterns suggested that wall motion dominates the flux reversal for films having a low coercive field; however, both the wall motion and rotational modes take place in a flux reversal for films having a high coercive field. Therefore, the hysteresis loops and angular dependence of the coercive field for CoCr sputtered films were calculated based on the assumption of a simultaneous occurrence of the rotational and wall motion modes. Good agreements were obtained between the experimental and calculated results.
Growth and Characterization of GaAs Layers Grown on Ge/Si Substrates by Metalorganic Chemical Vapor Deposition
Authors: Fukuda Yukio , Kadota Yoshiaki , Ohmachi Yoshiro
Published: February 2005

Epitaxial GaAs layers have been grown on (100) oriented Ge/Si substrates by metalorganic chemical vapor deposition. Double-crystal X-ray diffraction shows that the full width at half maximum of the (400) reflection obtained from 3 µm-thick GaAs is as small as 114 arc seconds. The GaAs surface dislocation density estimated by a molten KOH study is 4.9×106 cm-2. Photoluminescence measurements show that an excitonic transition at 1.4852 eV dominates at 4.2 K. These results suggest that Ge/Si substrates are suitable for growing sufficiently high quality GaAs layers.
A Computer Analysis of Effects of Annealing on InP Insulator-Semiconductor Interface Properties Using MIS C-V Curves
Authors: He Li , Hasegawa Hideki , Sawada Takayuki , Ohno Hideo
Published: February 2005

The effects of annealing on the distributions of interface states at the I-S interface were investigated by analyzing the C-V characteristics of as-grown and annealed Al2O3/native oxide/InP MIS capacitors using a self-consistent computer simulation program. It is shown that interface states form a continuum of donor-like and acceptor-like states continuously distributed both in energy and in space. The state density distribution before and after annealing maintains the same functional form, which is U-shaped in energy and exponentially decaying in space. The charge neutrality point dividing donor-like and acceptor-like states occurs at the U-shaped minimum. Annealing reduces the spatial extension of states, the U-shape curvature and the magnitude of density. However, the energy position of the charge neutrality point remains remarkably invariant.
Microstructure of SnO2 Conductive Film Prepared by Pyrohydrolytic Decomposition onto a Glass Substrate
Authors: Fujimoto Masayuki , Nishi Yuji , Ito Atsuo , Mishuku Toshio , Iida Hideyo , Shirasaki Shinichi
Published: February 2005

The microstructure of a thin SnO2 film prepared by pyrohydrolytic decomposition onto a glass substrate was studied by scanning transmission electron microscopy (STEM) and high-resolution transmission electron microscopy (HR-TEM) of cross-sectional specimens, and the findings were correlated with the low resistivity shown by this material when employed as a transparent electrode. The thin film was found to consist of three regions: a region which showed reaction with the glass substrate, a non-oriented polycrystalline region and an oriented columnar polycrystalline region showing a crystallographic shear (CS) structure which was thought to contribute to the low resistivity.
A Wide-Band Polymer Ultrasonic Transducer Using Acoustic Impedance Matching Technique
Authors: Kimura Kuniko , Yoneya Kazuyuki , Ohigashi Hiroji
Published: February 2005

A wide-band polymer ultrasonic transducer having acoustic impedance matching layers is proposed. In this transducer, a polystyrene or polypropylene matching layer is bonded onto the front surface of a piezoelectric film of vinylidenefluoride and trifluoroethylene copolymer (P(VDF-TrFE)). The matching layer, λ/4 thick, is most effective for obtaining a wider-band frequency response and sharper impulse response operating in water. Analytical and experimental results proved that the matching layer brings about a depth resolution 1.7 times higher than that of a conventional P(VDF-TrFE) transducer without any reduction in sensitivity. A medical ultrasonic image taken with the new transducer shows its usefulness for practical applications.
Properties of the S/N Ratio of the Beat Note in Frequency-Mixing Using the W-Ni Point Contact Diode at 32 THz
Authors: Kurosawa Tomizo
Published: February 2005

By mixing the radiation from two CO2 lasers (about 10 MHz apart, oscillating at R(24) of the 9.4 µm band in a W-Ni diode) the S/N ratio of the beat note was measured as a function of the incident laser power, the distance from the focal point of a lens, the incident angle onto the diode, the detected dc voltage, and the diode resistance. Furthermore, for frequency-mixing between R(24) and R(26) of the 9.4 µm band, the dependence of the S/N ratio on the diode resistance, the incident power of the CO2 laser and the microwave radiation on the diode is described. The detector performance is evaluated regarding the responsivity, effective coupling efficiency and noise equivalent power.
Photoluminescene of KTaO3 under Electric Field
Authors: Yamaichi Eiji , Ohno Shunichi , Ohi Kikuo
Published: February 2005

The photoluminescence in undoped KTaO3 crystal has been measured under static electric fields at 49 K. When a voltage is applied to the crystal, the intensity of the blue emission band decreases, and the emission spectrum becomes a yellow emission band. It is shown that these effects are caused by an increase of the temperature in KTaO3 as a result of Joule heating.
Hard Magnetic Properties of Nd-Fe-B Alloys Crystallized from Amorphous Phase
Authors: Hatta Shin-ichiro , Mizoguchi Tadashi
Published: February 2005

The hard magnetic material with a maximum
i

H

c
of about 30 kOe was obtained by crystallizing Nd-Fe-B alloys from the amorphous phase. The hard magnetic properties are considered to be due to single domain behaviors of the Nd2Fe14B fine grains, which are precipitated by annealing at 600-800°C for less than 3 min. When the specimens are further crystallized, Nd2Fe17 or α-Fe appears at the expense of the region of Nd2Fe14B phase.
Gain Characteristics of Hollow Cathode He-Cd+ White Light Laser
Authors: Fuke Akira , Masuda Katsuhiko , Tokita Yasuhiro
Published: February 2005

The hollow cathode He-Cd+ white-light laser simultaneously oscillates at three primary colors of light (red, green, and blue) in the visual range. The red output has wavelengths of 636.0 nm and 635.5 nm; the green output has wavelengths of 537.8 nm and 533.7 nm; and the blue output has a wavelength of 441.6 nm. The authors measured the small signal gains of these five wavelengths using an amplifier method. The three color outputs radiated from the oscillator tube were directed into an amplifier tube in order to measure the dependence of the gain coefficient on the anode current and the He pressure for each wavelength.