bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-Linearity in Position Sensing with Cathode Strips of a Single Wire Proportional Counter
Authors: Ohgaki Hideaki , Kondo Shingo , Uehara Seiji , Fujiki Toshihiro , Ijiri Hidenobu , Matoba Masaru , Sakae Takeji , Koori Norihiko
Published: February 2005

The nonlinearity in the position readout from cathode strips has been investigated by a single-wire proportional counter using the charge-division method. The measured nonlinearities depended on the width of the cathode strip. This dependence agrees very well with theoretical predictions based on the formulate of Gatti et al. and Gordon and Mathieson. Obtainable position resolutions are independent of the strip width.
Formation of Nickel Oxyhydroxide Thin Films by Electrodepositon and Their Electrochromic Characteristics
Authors: Morisaki Shigeyoshi , Kawakami Koichi , Baba Nobuyoshi
Published: February 2005

Electrochromic nickel oxyhydroxide films were formed by an electrodeposition method from 0.005 M NiSO4+0.015 M (NH4)SO4 solution, and their memory characteristics, response time and operation lifetime were investigated. The films prepared were porous with a network structure. They were colorless and transparent in a lower oxidation state [Ni(OH)2], but were dark brown in a higher oxidation state [NiOOH]. By heat-treating the films at 250degC for 15 minutes, electrochromic characteristics such as the operation lifetime could be remarkable improved.
Molecular Beam Flux Monitor Using Cold Cathode Discharge Induced Emission Spectroscopy
Authors: Sakai Junro , Chen Guorong , Hirama Kimiaki , Murakami Shun-ichi , Ishida Tetsuo
Published: February 2005

Cold Cathode discharge induced Emission Spectroscopy (CCES) was developed in order to apply a multiple molecular beam flux monitor for molecular beam epitaxy. The response characteristics of the emission intensity were in proportion to the molecular beam flux intensity under the MBE growth condition. The arsenic atomic emission intensity was satisfactorily, corresponding to the As4 molecular beam pressure. The detectable wavelengths of Al, Ga and As were found to be λ (Al)=309 nm, λ (Ga)=294, 417nm and λ (As)=194nm, which did not interfere with each other. When the growth rate of Al was at 0.1 nm/s, and the CCES had an accuracy of 0.1±0.0023 nm/s. The CCES directly controlled the Ga beam flux. The Ga beam pressure directly reflected the response time of the CCES control.
KrF Excimer Laser Projection Lithography: 0.35µm Minimum Space VLSI Pattern Fabrication by a Tri-Level Resist Process
Authors: Sato Takashi , Nakase Makoto , Nonaka Misako , Higashikawa Iwao , Horiike Yasuhiro
Published: February 2005

An excimer laser exposure system has been newly developed, which adopts a 0.37 NA achromatic projection lens and a 248 nm wavelength KrF excimer laser as a light source. Irregular PMMA development was observed for exposures on a silicon substrate. Theoretical simulation clarified that an initial 0.02 µm thickness variation caused more than 0.16 µm thick resist residues due to intense standing waves. The standing waves could be suppressed by the use of a tri-level resist process so that VLSI patterns of 0.35 µm minimum space could be obtained.
Determination of Ruby R-Lines Profile by Tunable Dye Laser
Authors: Noda Yoshitoshi
Published: February 2005

The R-line profile in a ruby of chromium concentration=0.065 wt% was determined by a nitrogen laser-pumped nile blue dye laser (spectral resolution=0.01 nm). This profile is much clearer than that obtained by the usual spectrometer method, and shows no splitting of the line in R1-line center (694.3 nm) at room temperature. The numerical value of the absorption coefficient α obtained by this method is compared with that of the other method.
Ultra-High Throughput of GaAs and (AlGa)As Layers Grown by Molecular Beam Epitaxy (MBE) with a Specially Designed MBE System
Authors: Sonoda Takuji , Ito Michihiro , Segawa Kazuaki , Takamiya Saburo , Mitsui Shigeru
Published: February 2005

The ultra-high throughput of extremely uniform GaAs and (AlGa)As layers with excellent surface morphology can be realized by MBE with a new MBE system designed for both a drastic increase of the throughput and a reduction of the surface defect density. The simultaneous growth of seven 5-cm-dia. epiwafers can be achieved with a thickness variation of less than 2% by optimizing the effusion cell geometry. A computer-controlled growth sequencer and a newly developed source recharging system are incorporated for automatic growth, and operated continuously day and night without venting the growth chamber even during source recharging. The surface defect density has been reduced to less than 50/cm2 by the introduction of a modified Ga cell and a face-down sample-transfer system. This system allows the growth of nearly 100 GaAs FET or HEMT wafers each day (24 hr). The devices constructed from these wafters showed excellent performance.
Analysis of Frequency Response Characteristics of Polymer Ultrasonic Transducers
Authors: Ohigashi Hiroji , Itoh Toru , Kimura Kuniko , Nakanishi Toshiharu , Suzuki Miyo
Published: February 2005

Piezoelectric polymers have large dielectric and mechanical internal losses. In this study, we introduced internal losses into Mason's equivalent circuit, and analyzed the effects of these losses on the transducer response, mainly in the frequency domain. To prove the validity of the theoretical analysis, we fabricated polymer transducers of several backing load types which are effective for practical use, using vinylidene fluoride and trifluoroethylene copolymer films, and evaluated their frequency and impulse responses. The experimental results are in good agreement with the theoretical prediction. We conclude that a consideration of the internal losses is essential for the proper design and correct evaluation of polymer transducers.
Preparation of Zinc- and Aluminum-Substituted Cobalt-Ferrite Thin Films and Their Faraday Rotation
Authors: Suzuki Koichiro , Namikawa Tatsuru , Yamazaki Yohtaro
Published: February 2005

Zinc- and aluminum-substituted cobalt-ferrite thin films were prepared on fused quartz substrates using vacuum evaporation followed by heat treatment. Magnetic measurements and X-ray diffraction analyses of the films showed that zinc and aluminum were successfully substituted in the spinel lattice and that the Curie temperature was reduced by both substitutions. The Faraday rotation spectra of the films were measured and the difference between Co-ferrite, CoZn-ferrite- and CoAl-ferrite films are discussed considering the distribution of Co2+ and Fe3+ over the lattice sites and the difference of the lattice constants. The performance factor of the films was improved around 800 nm by zinc substitution and around 1500 nm by aluminum substitution.
Numerical Solution of Landau-Lifshitz-Gilbert Equation with Two Space Variables for Vertical Bloch Lines
Authors: Hayashi Nobuo , Nakatani Yoshinobu , Inoue Toshiaki
Published: February 2005

Detailed structures of two-dimensional vertical Bloch lines (VBL's) are obtained from first-principle calculations in which the Euler equation is solved by means of Newton's method. Starting from the thus-obtained equilibrium state, the Gilbert equation is solved using various numerical methods to examine their accuracy and extent of stability. The examined methods include the forward difference, the original and the so-called modified Dufort-Frankel, ADI, backward difference, and Crank-Nicolson methods. The results of the examination show the advantage of using the backward difference method and the risk of using the modified Dufort-Frankel method. Although both methods are found to be very stable, the modified Dufort-Frankel method has the possibility of yielding results that are completely different from what is believed to be an accurate solution. This paper describes the principles of the numerical methods examined and the results of the examination together with the derived detailed structures of two-dimensional VBL's.
Preparation and Properties of a-Si Films Deposited at a High Deposition Rate under a Magnetic Field
Authors: Ohnishi Michitoshi , Nishiwaki Hidenori , Uchihashi Kenji , Yoshida Kazuhiro , Tanaka Makoto , Ninomiya Kunimoto , Nishikuni Masato , Nakamura Noboru , Tsuda Shinya , Nakano Shoichi , Yazaki Takehito , Kuwano Yukinori
Published: February 2005

An rf plasma decomposition of SiH4 under a magnetic field was investigated. It was confirmed by the optical emission spectra that a high-electron-density plasma can be produced under a magnetic field. High-quality a-Si films with a photosensitivity of σph/σd of 7×105 were obtained at a high deposition rate of 10 Å/s under the magnetic field. The a-Si solar cells with i-layers deposited at a high deposition rate under a magnetic field have a higher open-circuit voltage and a higher conversion efficiency than those without the magnetic field; a conversion efficiency of 10.1% under AM1(100mW/cm2) illumination was obtained at a deposition rate of 10 Å/s. The rf plasma decomposition of SiH4 under a magnetic field is thought to be very suitable for fabricating a-Si solar cells with a high conversion efficiency at a high deposition rate.
Reflection of Ion Waves from a Bipolar Electrode in an Ion Beam-Plasma System
Authors: Noda Shunichi , Nakamura Yoshiharu , Kawai Yoshinobu , Akazaki Masanori
Published: February 2005

Wave reflection in an ion beam-plasma system was studied using a bipolar electrode as a reflector. For an incident beam mode, both the beam and the ion acoustic modes were observed. It was found that these reflected waves depend on the energy distribution of the reflected ions. Wave excitation by a grid is also discussed.
The Inverse Smith-Purcell Effect in the Submillimeter Wave Region –Theoretical Analyses–
Authors: Bae Jongsuck , Furuya Kazuyuki , Shirai Hirokazu , Nozokido Tatsuo , Mizuno Koji
Published: February 2005

The inverse Smith-Purcell effect is theoretically investigated in the submillimeter wave region for planning experiments. The effect in which coherent light waves interact with charged particles resonantly through a diffraction grating is one of the candidates for laser-driven linacs.
The optimum grating dimensions with a rectangular groove profile are designed by analyzing the fields just in front of the grating surface. The energy spreads of the electrons resulting from interactions with the laser field were evaluated by computer simulations. It can be seen from the simulations that a laser power of 1 W can produce ∼ 30 eV increase in the electron energy spectrum.
Size Distribution of Aerosol Produced from p-Dichlorobenzene by Ultraviolet Radiation
Authors: Sekiya Takashi , Yabuzaki Tsutomu , Kitano Masao , Ogawa Toru
Published: February 2005

The particle size distribution of aerosol produced from gaseous p-dichlorobenzene by the irradiation of UV light with a wavelength of 220 nm was measured by a light-scattering method. In particular, the temporal change was studied. First, many particles of radii smaller than 0.1 µm were produced homogeneously. The peak number density ∼3×106 particles/cm3 was achieved in 6 minutes. In about 20 minutes, the steady-state distribution was established, in which the most frequent radius was 0.2 µm, with a number density of about 5×105 particles/cm3. The breadth of the distribution first increased, but then decreased as time elapsed. At the steady state, the distribution was almost monodispersed.
X-Ray Sensing Pickup Tube
Authors: Suzuki Yoshio , Hayakawa Kazunobu , Usami Katsuhisa , Hirano Tatsumi , Endoh Tooru , Okamura Yoshinori
Published: February 2005

An X-ray sensing pickup tube free of white defects in the scanning area has been developed, and its characteristics have been evaluated. This pickup tube functions over a wide X-ray energy range, from 7 to 40 keV. The maximum spectral sensitivity, observed at a 20 keV photon energy, is 6×10-17 A/(photons/s). The limiting resolution is about 8µm. A preliminary study for monochromatic X-ray microradiography has also been performed.
Reflectance Spectra of BN Materials in the Vacuum Ultraviolet
Authors: Chayahara Akiyoshi , Yokoyama Haruki , Imura Takeshi , Osaka Yukio , Fujisawa Masami
Published: February 2005

The optical reflectance spectra of microcrystalline cubic and hexagonal BN films prepared by plasma CVD, a sintered cubic BN and a pyrolytic BN were measured in the energy range 5–25 eV with synchrotron radiation. For cubic materials, reflectance peaks appear near 11.4 and 14.0 eV. Hexagonal materials have peaks at 6.2, 7.0, 10 and 16 eV. The reflectivity peaks are interpreted using available experimental and theoretical data.
Dynamic Responses of Ferroelectric Liquid Crystals in the Surface-Stabilized Geometry I
Authors: Nakagawa Masahiro , Ishikawa Masahito , Akahane Tadashi
Published: February 2005

The dynamic response of surface-stabilized ferroelectric liquid crystals was studied on the basis of a continuum theory. In this work, polarization electric field was consistently introduced through Poisson's equation, including the polarization charge accompanied by an elastic deformation. An improved anchoring energy consistent with inclined smectic layers relative to the bounding plates is put forward. From numerically calculated results, the polarization current and the hysteresis curves are found to be crucially affected by the inherent chirality and the polarization electric field. Remarkably, it is shown that an increase of the inherent chirality or the negative dielectric anisotropy results in a doubly or a triply peaked polarization switching current under an alternating external field.
Threshold Behavior of a Bistable Ferroelectric Liquid Crystal with a Large Tilt Angle in Thick Cells (4-14µm)
Authors: Kondo Katsumi , Nagae Yoshiharu , Isogai Masato , Kitamura Teruo , Mukoh Akio
Published: February 2005

Threshold characteristics were measured of a cell consisting of a compound which shows a large tilt angle of 35° and possesses bistability in cells thicker than 4 µm. A value, which represents the sharpness of the threshold, V
sat
(max)/V
th
(min), of 2.5 was obtained at T-T
c=-20°C. The optical responses to two kinds of voltage waveform applications were also measured. The introduction of zero voltage periods improved the bistability and, consequently, made it possible to drive matrix displays.
In Situ IR Spectroscopic Study of a-Si:H Films Growing under Photo-Chemical Vapor Deposition Condition
Authors: Wadayama Toshimasa , Suëtaka Wataru , Sekiguchi Atsushi
Published: February 2005

Polarization modulation infrared spectroscopy has been successfully applied for in situ observations of a-Si:H films growing under photo-chemical vapor deposition conditions. The thin films exhibited absorption bands arising from SiH3 or SiH2 species, depending upon the substrate temperature. Whereas the mass thickness of the film deposited at 293 K increased in proportion to the deposition time, the IR absorption intensity of SiH3 species decreased in rate when the film grew beyond 15 Å in thickness, showing that the concentration of the SiH3 species becomes reduced with the deposition time. Although the band ascribable to the Si-O stretching vibration could not be observed during the deposition, it grew when the film was exposed to air. This fact suggests that the origin of the oxygen incorporated in the film is mainly atmospheric oxidizing agents.
Photo-Process of Tantalum Oxide Films and Their Characteristics
Authors: Matsui Masahiro , Oka Satoshi , Yamagishi Koji , Kuroiwa Koichi , Tarui Yasuo
Published: February 2005

TaO
x
film formation by a photo-CVD method using TaCl5 as a source material is examined. The deposition rate increases with increasing growth temperature and decreasing chamber pressure down to 1 Torr. The leakage current of the formed TaO
x
film decreases drastically with annealing in the presence of both UV-irradiation and an oxygen ambient after deposition (p-O2 annealing), when the underlying layer contains Si. The leakage current density is 10-8 A/cm2 at the 4 MV/cm electric field. The dielectric constant for MIS structure capacitors decreases with decreasing TaO
x
thickness, but does not decrease much with p-O2 annealing. In addition, the mechanisms of reduction of the leakage current with p-O2 annealing are discussed.
Thermal Stability of Hydrogen in Silicon Nitride Films Prepared by ECR Plasma CVD method
Authors: Hirao Takashi , Kamada Takeshi , Kitagawa Masatoshi , Setsune Kentaro , Wasa Kiyotaka , Matsuda Akihisa , Tanaka Kazunobu
Published: February 2005

Infrared (IR) absorption measurements, hydrogen evolution experiments and ESR measurements have been carried out in order to study the thermal stability of hydrogen, bond configuration and defect structure in silicon nitride films (SiN) prepared by an ECR plasma CVD method and in part by a conventional plasma CVD method. It is shown that the SiN films deposited at high microwave powers in which the bond configuration of N-H is predominant are thermally very stable, even after annealing at 900 °C in a dry N2 atmosphere. The IR spectra scarcely vary before and after the annealing. The hydrogen evolution from SiN films was found to be highly dependent upon the deposition conditions and deposition methods. The amount of hydrogen evolved after experiments up to 900 °C becomes less as the microwave power increases. The temperature at which hydrogen evolution starts to take place for SiN films deposited by the ECR plasma CVD method is generally higher than that for the P-CVD method, except for ECR SiN films deposited at high gas pressure. ESR measurements revealed that the hydrogen concentration in SiN films has little influence on the spin density.
Analysis of Impulse Response Characteristics of Polymer Ultrasonic Transducers
Authors: Kimura Kuniko , Ohigashi Hiroji
Published: February 2005

The impulse response characteristics of polymer ultrasonic transducers were analyzed using the Mason's equivalent circuit. These characteristics strongly depend on material factors of the piezoelectric polymer: the dielectric and mechanical internal loss factors, the electromechanical coupling factor and the acoustic impedance. Based on the analytical results, we evaluated the piezoelectric polymers that are presently available as transducing materials. The analytical results were verified experimentally using transducers composed of poly(vinylidene-fluoride) film and vinylidene fluoride and trifluoroethylene copolymer film.
Longitudinal Mode Competition and Asymmetric Gain Saturation in Semiconductor Injection Lasers. I. Experiment
Authors: Ogasawara Nagaatsu , Ito Ryoichi
Published: February 2005

Longitudinal mode competition in transverse-mode-controlled laser diodes has been experimentally investigated. A careful examination of the output power change associated with both random mode switching and hysteretic mode jumping has revealed a peculiar feature of mode competition in laser diodes; in most devices, the output power is decreased as the lasing mode jumps from a shorter to a longer wavelength mode, which it is increased at mode jumping toward shorter wavelengths. The peculiar feature has been interpreted in terms of an asymmetry in gain saturation, which was experimentally observed. A terminal voltage change associated with mode jumping has also been measured. In some devices, a small shift of the beam profile was observed at mode jumping.
Laser-Induced Fluorescence Study of Penning Collision of HeI 21S Atom with Xe in He+Xe Gas Discharge Plasma
Authors: Uchiike Heiju , Arinaga Kenji , Manabe Kazutaka , Shindo Haruo , Fukushima Yoshifumi , Tamaru Takeshi
Published: February 2005

This paper presents experimental results concerning the population of the 21S atom of HeI in a discharge plasma of a He+Xe gas mixture. The population measurement was made by the laser-induced fluorescence method with the laser light tuned to the HeI line of 5016 A(21S-31P). The fluorescence intensity of the HeI line was measured as a function of the discharge current at pressures ranging from 0.2 to 5.0 Torr, and the behavior of the fluorescence intensity was clarified in terms of the measured electron density. In the Xe-mixed gas, the fluorescence intensity was significantly reduced in the region of low electron density; this region extended to a higher electron density as the Xe gas content was increased. Thus, it was concluded that the population of the 21S state was dominated by Penning collisions with Xe atoms at low electron density.
Electrical Properties of Single Crystalline TiO2 Doped with Metallic Sodium Vapor
Authors: Maruyama Satoshi , Kitazawa Koichi , Fueki Kazuo
Published: February 2005

Single crystals of Na
x
TiO2 were prepared up to x=0.007 by heating single-crystalline TiO2 in Na vapor at 700°C or below. The electrical property of Na
x
TiO2 below the room temperature, down to 4.2 K, could be explained on the basis of the metal-insulator transition model for doped semiconductors. No essential differences were observed in the electrical properties between Na
x
TiO2 and reduced rutile (TiO2-y
) when the doping level was low (x=0.004). However, there was a significant difference between them in the case of heavy doping, i.e., the conductivity in the lowest temperature region was much higher in Na
x
TiO2 than in reduced rutile. This indicates that the donor level in Na
x
TiO2 remains shallow while that in reduced rutile becomes deeper in the heavily-doped region.
Photo-CVD SiN Assisted Self-Aligned Metal Contact Technology for High-Speed GaAs Devices–Recess Gate Structure with High Breakdown Voltage for GaAs FETs–
Authors: Usagawa Toshiyuki , Okuhira Hidekazu
Published: February 2005

A new self-aligned recess metal contact process utilizing photo-CVD SiN as a side-wall between the gate metal and the n
+ source region has been accomplished for recessed gate GaAs MESFETs with a single lithographic procedure. The process achieves excellent transconductance, G
m, of 190∼240 mS/mm for a gate length, L
g, of 1.2 µm with keeping the source-gate breakdown voltage as high as 7-14 V.
Soft X-Ray Optical Constants: Pt, Ag, and Cu
Authors: Yanagihara Mihiro , Niwano Michio , Koide Tsuneharu , Sato Shigeru
Published: February 2005

The optical constants of Pt, Ag, and Cu in the soft X-ray region (100-1200 eV) derived from the reflectance method are reported. Samples were thickly deposited on substrates so that interference effects would be negligible. Using Debye-Waller and constant factors we could explain the angular dependence of the specular reflection of the soft X-rays from conventionally-evaporated mirrors.
Empirical Relation between Transition Temperature and Work Function in Elemental Superconductors
Authors: Koshida Nobuyoshi
Published: February 2005

It is shown that in elemental superconductors, there exists some degree of correlation between transition temperature T
c and work function φ. The T
c-φ curve exhibits an oscillatory behavior. For both transition and nontransition elements, an optimum condition for T
c occurs at φ=4.0 eV. To determine if this rule is available for new high-T
c oxides, systematic studies for determination of their φ values are required.
Thin Crystal Growth of Alkali Halides from Melt by Using Quartz Cell and Their Optical Properties Due to Excitons
Authors: Hashimoto Satoshi , Itoh Minoru
Published: February 2005

A growth method has been developed for preparing thin alkali halide crystals of thicknesses from 0.05 to 50 µm. In this method, the melt is introduced, through capillary action, into a narrow gap between two parallel quartz plates and allowed to solidify. Optical properties of these thin crystal have been measured low temperatures. As an example of this, we examine the case of KI, in which the absorption and emission spectra of excitons are discussed in comparison with those obtained in bulk crystals.
Galvanomagnetic Effect of an Y–Ba–Cu–O Ceramic Superconductor and Its Application to Magnetic Sensors
Authors: Nojima Hideo , Tsuchimoto Shuhei , Kataoka Shoei
Published: February 2005

The galvanomagnetic effect of a ceramic superconductor Y1Ba2Cu3O7-x
was measured. It was found that when a magnetic field of a certain small value applied, the electric resistance of this material suddenly increases very rapidly from zero with increases in the applied magnetic field. The magnetic field at which the resistance appears is controllable by changing the magnitude of a current through the material. This effect is characterized by a very high magnetic sensitivity at low magnetic field. This is quite useful as a highly sensitive magnetic sensor both in digital and analogue operations. This magnetic sensor using the ceramic superconductor has many advantages over the conventional semiconductor magnetoresistive sensor.
Characterization of High-Efficiency Cast-Si Solar Cell Wafers by MBIC Measurement
Authors: Shimokawa Ryuichi , Hayashi Yutaka
Published: February 2005

Cast-Si wafers for high-efficiency solar cells were characterized by MBIC measurement, in which the minority-carrier recombination loss at structural defects were seen as a drop in intensity. Cast-Si wafers contained a large number of non-planer and irregular grain boundaries, the majority if which had the electrical activity greatly due to a slight difference in the crystal orientation. These boundaries were classified into three geometrical structures, that is, columnar-structure grain boundary (GB), tilt-structure GB and GB structure with a transition interface layer. Other dominant defects were planar boundaries, {111} twin boundaries, {221} second-order twin boundaries and {221} planar boundaries without a twinning relationship (symmetric twist boundaries) which were found to be electrically inactive and were mainly observed in the high-quality wafers. Besides, the boundary structures off the twinning relationship, fine-crystalline structures and subgrain boundary structures were found to have remarkable electrical activity.
Dark Current in Selectively Doped N-AlGaAs/GaAs CCDs
Authors: Akatsu Yuji , Ohno Hideo , Hasegawa Hideki , Sano Naokatsu
Published: February 2005

The dark current of Schottky-barrier gate charge-coupled devices (CCDs) utilizing selectively doped N-AlGaAs/GaAs structures grown by molecular beam epitaxy was investigated. The generation rate of carriers in the CCD channel, i.e. the dark current, and its temperature dependence were measured in detail. The dark current was dominated by the reverse current of the Schottky barrier gate and consisted of the reverse current of the operating gate as well as that of the neighboring two gates. The reverse current was shown to be dominated either by the thermionic-field emission current or by the field emission current because of the high doping of AlGaAs. A measure of the reduction of the reverse current is also presented.
Stark-Broadening of Ar I Lines
Authors: Abbas A. , Basha T. S. , Abdel-Aal Z. A.
Published: February 2005

The half-width and shift of some Stark-broadened Ar I lines are measured using a highly-stabilized argon arc at different electron densities. The relation of the ratio of the half-width over the plasma electron density as a function of the electron density itself, for the isolated argon line, 4300 Å, shows an excellent agreement with the theory. This argon line may therefore be used for the accurate determination of the electron density in argon plasma sources. The line profile is analysed and discussed.
Half-Width, Shift and Transition Probability of Ar II Lines
Authors: Abbas A. , Basha T. S. , Abdel-Aal Z. A.
Published: February 2005

The half-width, line shift, transition probability, lifetime, oscillator strength and profile of some Ar II lines are investigated using a high-current wall-stabilized arc with argon flow around the electrodes and in the middle of the arc. The arc plasma is operated with currents from 40 to 125 amperes, corresponding to an arc temperature in the range 12,000 to 17,000 K. The experimental results are compared theoretically and with data reported by others; a fair agreement is obtained for most of the present results. The effect of pressure on Ar I and Ar II lines is discussed.
Charge Waveform of a New Two-Dimensional Position-Sensitive Silicon Detector
Authors: Hasebe Nobuyuki , Ezawa Yasuo , Yoshii Hisashi , Yanagimachi Tomoki
Published: February 2005

The operation principles of the two-dimensional position-sensitive silicon detector newly developed by Doke et al. were studied using a simple model. This model treats the detector as an area of continuously distributed capacitance C and resistance R

s
of position surface layer. A linear relationship can then be obtained between the position of the incident particle and change collected at the contacts of the detector. The kinetics of charge collected at corner contacts, ballistic deficit and noise were calculated. Rise time of the charge pulse (10–90%) was found to vary with the position of incidence up to about R

s

C/8. It was found that a shaping time constant longer than R

s

C/3 is required for pulse shaping with single CR-differentiation and single CR-integration in order to obtain a ballistic deficit of less than 1%.
Investigation of Magnetic Field Properties in the Helical Axis Stellarator: Asperator NP-4
Authors: Funato Yasuyuki , Kitajima Sumio , Watanabe Hiroshige
Published: February 2005

Experimental measurements of the magnetic field properties of a helical axis stellarator were carried out. The results, together with the numerical calculation, are described herein. The toroidal device, Asperator NP-4, has a helical magnetic axis with a pitch angle of 45° and a multi-field period of n=8. The magnetic field of NP-4 is produced by the currents of helical solenoids and L=+1, -1 helical windings. By an electron beam mapping of field lines, the existence of a high rotational transform angle and magnetic surfaces are confirmed and the position if the helical magnetic axis is obtained. The other fundamental magnetic properties such as the shear and the specific volume of the configuration are also deduced from the measurements. Numerical calculations lead to a good agreement with the results of the experiment.
Electrical Properties of Bromine-Doped Nickel (Phthalocyanine) Films and Their Structural Change
Authors: Nakamura Shuhei , Amatatsu Hiroshi , Ozaki Tamon , Yamaguchi Shinji , Sawa Goro
Published: February 2005

The change in electrical conductivity of bromine-doped nickel phthalocyanine (Ni(Pc)) film doping level has been studied based upon the analysis of the film structure. The electrical conductivity of bromine-doped Ni(Pc) films exhibits a maximum and minimum at doping levels x(=Br/Ni)≃ 1 and 4, respectively. Its apparent activation energy also shows a minimum and maximum, which respectively correspond to the maximum and minimum of the electrical conductivity. It was concluded that the decrease in conduction accompanied by the decrease in activation energy with doping level in the range (1<x<4) arises from the decrements in both the number of electrical conduction paths and charge carriers due to cracks on the film surface, and from the morphological change from polycrystalline into amorphous structures. It is, however, uncertain why the electrical conductivity again increases above x≃4.
Effects of Refraction of X-Rays in Double-Crystal Topography
Authors: Niwano Michio , Kanai Akira , Suemitsu Maki , Nakamura Hirofumi , Miyamoto Nobuo
Published: February 2005

We have investigated the effects of refraction of X-rays in double-crystal topography in the (+, -) Bragg-Bragg asymmetric arrangement, in which the angle of incidence of X-rays is very small. It is shown that in a double-crystal topograph of a sample having an uneven surface, the refraction effect gives rise to diffraction contrasts corresponding to the shape of the sample surface. This effect can be applied to an examination of surface roughness of a crystal and to a determination of a refractive index in the X-ray region. An attempt to derive the refractive index for silicon crystals has been made. The derived value was found to be in good agreement with the nominal one.
Evaluation of LB Films as Quarter Micron Lithography Resists Using Excimer Laser, X-Ray, and Electron Beam Exposure
Authors: Ogawa Kazufumi
Published: February 2005

An evaluation of LB films was performed to determine whether or not LB films were applicable to quarter micron lithography using excimer laser (EX), X-ray and electron beam (EB) exposure. The pattern resolution and sensitivity were investigated on seven kids of LB films. The highest resolutions obtained were 0.3 µm for pentacosa diynoic acid (PDA) using EX exposure, 0.4 µm for ω-tricocynoic acid (TCA) using X-ray exposure and 0.2 µm for TCA using EB exposure. On the basis of these results, it was concluded that quarter micron lithography would be possible on LB films using the former two methods if the resolution of the lens for EX exposure was improved and a mask having finer patterns for X-ray exposure was obtained.
Crystallization of Amorphous Zr–20 at%Ni Alloy
Authors: Asahi Nobuo , Miyashita Akira
Published: February 2005

The crystallization process of an amorphous Zr80Ni20 alloy was investigated by X-ray diffractometry, electrical resistivity measurement and differential scanning calorimetry (DSC). The resistivity (at 300 K) of amorphous ribbon used in this experiment was 1.7 ×102 µΩ·cm. The temperature coefficient of resistivity was -1.04 ×10-4/K, in the region between 300 and 370 K. The crystallization temperature determined by resistivity measurement was 615 K. The activation energies for the crystallization were found to be 2.4 eV from the resistivity data and also 2.5 eV from DSC data. A time-temperature-transformation (T-T-T) diagram consisting of two straight lines was obtained.
The Effect of Interposing Thin Oxide Layers on the Photovoltaic Properties of a-Si:H Solar Cells. I. Between a-Si:H and Transparent Conductive Oxide Layers
Authors: Sakai Yuichi , Fukuyama Keiichi , Matsumura Michio , Nakato Yoshihiro , Tsubomura Hiroshi
Published: February 2005

The open-circuit voltages (V
oc) of Schottky-barrier type, hydrogenated-amorphous-silicon (a-Si) solar cells having structures [glass/fluorine-doped SnO2/metal-oxide/i-p a-Si/Ag] and [glass/SnO2(F)/metal-oxide/i-n a-Si/Ag] with NiO, SnO2(F), TiO
x
, Fe2O3, WO3, and V2O5 as the interposed metal-oxides, were studied and discussed on the basis of the work functions of the metal-oxide layers determined experimentally. Metal-oxides having small work functions, such as NiO and SnO2(F), gave high V

o
c
for the former-type cells, while those with large work functions, such as V2O5, gave high V
oc for the latter-type cells. Similar studies were also made for p-i-n type a-Si solar cells. For p-i-n cells with the p-layer thinner than 10 nm, the V
oc was enhanced by interposing a very thin V2O5 layer between the SnO2(F) layer and the p-layer.
Growth Modes of MBE and SPE in the Heteroepitaxy of a NiSi2 Layer on Si(111) Substrate
Authors: Ishizaka Akitoshi
Published: February 2005

The growth mechanism of NiSi2/Si(111) heteroepitaxy by molecular beam epitaxy (MBE) was studied as a function of substrate temperature. Growth modes of the epitaxy were classified into these kinds: 1) two-dimensional epitaxy at ledge, 2) two-dimensional epitaxy at kink, and 3) three-dimensional epitaxy. The temperature regions corresponding to these growth modes were ∼1/4– ∼1/2T
m, ∼1/2– ∼3/4T
m, and \gtrsim3/4T
m, respectively, where T
m (°K) is the melting point of NiSi2. By comparing these results with those of the various MBE material systems, e.g., Si/Si, GaAs/GaAs, Ga0.7Al0.3As/GaAs and InP/InP systems, the relation between growth mode and epitaxial temperature range was found to be almost the same. The epitaxial layers with high crystallinity and smooth surface morphology grew in the region of 2) of the above classification.
Magnetic Properties and Magnetic Anisotropy Dispersion of Fe/Ni–Fe Multilayered Films
Authors: Nakatani Ryoichi , Kobayashi Toshio , Ootomo Shigekazu , Kumasaka Noriyuki
Published: February 2005

Fe/Ni–Fe multilayered films are formed by the ion beam sputtering method. Their magnetic properties and film structures are examined. As the period of the Fe/Ni–Fe multilayered films is reduced, the Fe crystallite diameter and the magnetic anisotropy dispersion become small and the soft magnetic properties are improved. The Fe/Ni–Fe multilayered film, whose period is 25 nm, displays a coercive force of 90 A/m, a relative permeability of 1900, a saturation magnetic flux density of 1.9 T, and a magnetostriction constant of 8×10-7. It is thought that the reduction of magnetic anisotropy dispersion improves the soft magnetic properties of Fe/Ni–Fe multilayered films.
Magnetic Field and Temperature Dependences of the Magnetic Aftereffect in Sm2Co17 Sintered Magnet
Authors: Nishio Hiroaki
Published: February 2005

One of the intrinsic instabilities of permanent magnets is magnetic aftereffect. The magnetic field and temperature dependences of the magnetic aftereffect constant, S
v, were measured for a Sm2Co17 sintered magnet under the effective magnetic field, H
eff, ranging from -230 to -700 kA/m and at a temperature range from 77 to 473 K. Through these experiments the following results were obtained: The magnetic aftereffect constant, S
v, is independent of the magnetic filed at 77 K, and scarcely varies in the field ranging from the point of (B
H)max to H
CB and in the temperature range from 270 K to 470 K. Also in the results of measuring S
v, and time dependence of magnetization at room temperature for 1000 h, it was found that the optimum magnetic field condition for stabilized demagnetization coincides with the magnetic aftereffect field, H
k.
Single Silicon Etching Profile Simulation
Authors: Arikado Tsunetoshi , Horioka Keiji , Sekine Makoto , Okano Haruo , Horiike Yasuhiro
Published: February 2005

Single Si etching profile by Cl2 and a mixture of Cl2 and CHF3 are discussed in terms of experimentation and simulation. A microprobe Auger analysis of a trench side wall has proven that the bombardment of obliquely impinging ions to a side wall leads to both concave and tailed features. In the case of a mixture of Cl2 and CHF3, the polymer film produced by CHF3 protects the side wall from species impinging from an inclined direction. Furthermore, the difference in the polymer sputtering rate, resulting from subsequently impinging ions between the tailed part and the flat bottom regions improves the tailed part to the rectangular bottom. A profile simulation supports the idea that obliquely impinging species, polymer deposition and sputtering of a polymer are important factors in determining the single Si etching profile.
Critical Slowing Down of the Spin Relaxation and Center Shift Anomaly in NiFe2O4 Observed with Mössbauer Spectroscopy
Authors: Uen T. M. , Yang F. H.
Published: February 2005

Detailed Mössbauer-effect studies of NiFe2O4 were carried out in the temperature range from 13.4 to 890 K. The respective temperature dependences of the center shifts, the hyperfine fields, and the longitudinal relaxation rates of the spin fluctuation were determined for both A- and B-site ferric ions. An anomalous change in the slope of the center shift of the B-site ferric ion was clearly observed near 475 K. The Néel temperatures and the critical exponents of the average spins were determined for the A- and B-site ions. It was also observed that the spin relaxation rates decreased remarkably in the critical region. The exponents which characterized the critical slowing down of spin relaxation were also determined.
Barrier Height of Metal/InP Schottky Contacts with Interface Oxide Layer
Authors: Yamagishi Haruo
Published: February 2005

The barrier height qφB for metal/InP Schottky contacts with an interface oxide layer formed by exposing an InP surface to microwave-induced oxygen radicals has been studied as a function of metal work function qφm·qφBn (qφBp) for n (p)-type InP contact is found to increase (decrease) linearly with increasing qφm for a fixed oxide layer thickness. Sum of qφBn and qφBp for each metal is found to roughly coincide with the band gap of InP. Based on the interface layer theory which considers fixed charges at the interface between the oxide layer and the semiconductor, the dielectric constant for the oxide layer εi of ∼6ε0, the interface state density D
s of ∼2×1013 eV-1·cm-2 and the positive interface fixed charge density Q
s/q of ∼5×1012 cm-2 have been evaluated, indicating that the volume charge within the oxide layer is negative.
Determination of Chevron Direction and Sign of the Boat-Shaped Disclination in Surface-Stabilized Ferroelectric Liquid Crystals
Authors: Hiji Naoki , Ouchi Yukio , Takezoe Hideo , Fukuda Atsuo
Published: February 2005

On the basis of a smectic layer bend (chevron) structure confirmed recently, the absolute configuration of a zigzag defect and a boat-shaped disclination loop were investigated in surface-stabilized ferroelectric liquid crystal (SSFLC) cells. Comparing the color of the SSFLC state stabilized by a lateral electric field with the color calculated by a suitable model, the following configurations were clarified: 1) the apices of lightning and the thick lines of hairpin zigzag defects correspond to \lll* \ggg and \ggg* \lll, respectively, and 2) the bow and the stern of boat-shaped domains correspond to +2 π and -2 π wedge disclinations, respectively.
Preparation and Physical Properties of Y1-xCa1.1xBa2-0.1xCu3Oy
Authors: Kosuge Michikazu , Okai Bin , Takahashi Koh , Ohta Masatsune
Published: February 2005

The Y-Ca solid solution of the “1-2-3” crystal structure with composition Y1-x
Ca1.1x
Ba2-0.1x
Cu3O
y
(0<x<2) was prepared. An excess of 10% of Ca ions which occupied Ba sites was necessary for obtaining a single phase. The superconducting transition temperature T
c steadily decreases with increasing x, while the change of valence of Cu is not uniform with x from 0 to 0.2. The relationship between T
c and the valence of Cu was discussed.
Preparation of High-Tc (110 K) Superconducting Phase by the Annealing of Low-Tc (80 K) Superconductor Bi2(Sr0.5Ca0.5)3-xCu2Oy
Authors: Wada Takahiro , Suzuki Nobuo , Maeda Atsutaka , Uchida Shin-ichi , Uchinokura Kunimitsu , Tanaka Shoji
Published: February 2005

The high-T
c (110 K) superconducting phase of Bi-Sr-Ca-Cu-O system is obtained by the transformation of the low-T
c (80 K) phase, Bi2(Sr0.5Ca0.5)3-x
Cu2O
y
[x=0, 0.1, 0.2, 0.4] through long time sintering. One sample with x=0.4 whose sintering temperature is 868°C shows zero resistivity at 106 K and a sharp onset of the diamagnetic susceptibility. The Meissner signal reaches about 30% of the ideal value at around 100 K. The relation between starting composition and the process of the formation of the 110 K phase is briefly discussed, based on the results of ac and dc magnetic susceptibility measurements.
Synthesis and Superconductivity of a New High-Tc Tl-Ba-Ca-Cu-O Phase
Authors: Kikuchi Masae , Kobayashi Norio , Iwasaki Hideo , Shindo Daisuke , Oku Takeo , Tokiwa Ayako , Kajitani Tsuyoshi , Hiraga Kenji , Syono Yasuhiko , Muto Yoshio
Published: February 2005

A 120 K-class superconductor in the Tl-Ba-Ca-Cu-O system was synthesized, and the flux exclusion proved to be greater than 90% of the perfect diamagnetism. X-ray and electron diffraction studies showed a tetragonal unit cell with lattice parameters a=5.4454(7) Å and c=35.586(9) Å, indicating triple perovskite-like layers interposed between Tl2O2 layers. A structure model is proposed, in which the layer sequence along the c-axis is Tl2O2-BaO-CuO2-Ca-CuO2-Ca-CuO2-BaO. The chemical composition is Tl2Ba2Ca2Cu3O10+x
assuming trivalent thallium. If the same average Cu valence as in YBa2Cu3O7 is assumed, this composition requires x=0.5 for oxygen.
Intergrowth Structures in Superconductor Tl-Ba-Ca-Cu-O Oxides
Authors: Iijima Sumio , Ichihashi Toshinari , Shimakawa Yuichi , Manako Takashi , Kubo Yoshimi
Published: February 2005

Direct read-out of metal atom coordinates from HREM images was performed on superconductive Tl-Ba-Ca-Cu-O (TBCCO) oxide crystals. The technique permits examination, in a quantitative fashion, of crystal structures including stacking disorders. Some ordered intergrowth structure for TBCCO oxides, beside the Tl2Ba2CaCu2O8+x
(2212) and Tl2Ba2Ca2Cu3O10+x
(2223) phases, were observed, and their structure were identified as sequences of structure with a single Tl-O sheet instead of double Tl2O2 sheets, a chemical formula TlBa2Ca2Cu3O9+x
, has been confirmed.
Effect of Lattice Distortions on 90-K Class Superconductors: Y1-xEuxBa2Cu3O7-δ, Yb1-xSmxBa2Cu3O7-δ and Eu(Ba1-xSrx)2Cu3O7-δ
Authors: Taguchi Isao
Published: February 2005

X-ray powder diffraction studies show that an oxygen deficient perovskite structure is preserved in the whole range of x for the Y1-x
Eu
x
Ba2Cu3O7-δ and Yb1-x
Sm
x
Ba2Cu3O7-δ system. Resistivity measurements do not show a strong x-dependence of T
c for either system which has the large difference of ionic radius between Y and Eu or Yb and Sm. In contrast, T
c is more strongly depressed in the Eu(Ba1-x
Sr
x
)2Cu3O7-δ system than in the Y(Ba1-x
Sr
x
)2Cu3O7-δ system. This result gives suggestion that the decrease of T
c is due to local distortions of the CuO2 planes induced by Sr substitutions on the Ba sites.
Observation of Donor-Related Deep Levels in GaxIn1-xP (0.52≤x≤0.71)
Authors: Kitahara Kuninori , Hoshino Masataka , Ozeki Masashi
Published: February 2005

This paper reports donor-related deep levels in Ga
x
In1-x
P (0.52≤x≤0.71). S-, Se- and Si-doped GaInP grown by chloride-vapor-phase epitaxy were used for the measurements. At the Ga composition x of 0.52 that is lattice matched to GaAs, a deep level was observed for S-doped GaInP but not for Se- or Si-doped GaInP. Se-doped GaInP with larger x values was also studied, and the deep level was observed for x larger than 0.56. It is found that the behavior due to these donor-related deep levels, with effects such as persistent photoconductivity and Ga-composition dependence, is the same as for DX centers in AlGaAs.
Josephson Effects at 77 K in Grain Boundary Bridge Made of Thick Films
Authors: Yamashita Tsutomu , Kawakami Akira , Noge Satoru , Xu Weiwei , Takada Masasuke , Komatsu Takayuki , Matsusita Kazumasa
Published: February 2005

Using the screen printing method, YBaCuO high T
c superconducting films were fabricated. The thickness of the films was ≃30 µm and maximum grain size was ≃70 µm. T
czero=90.7 K and J
c=20 A/cm2 at 77 K were obtained. With a razor edge, the films were cut and formed to grain boundary bridges having a few grain boundaries in the bridge region. The devices showed clear Shapiro steps and SQUID patterns at 77 K.
High-Tc Superconducting Film on Silicon Substrate with ZrO2 Buffer Layer
Authors: Kitagawa Takeshi , Shibata Shuichi , Okazaki Hisaaki , Kimura Takao , Enomoto Youichi
Published: February 2005

A screen-printed YBa2Cu3O7-x
superconducting film with T
c,zero=85 K has been fabricated on a ZrO2-coated silicon substrate made by the sol-gel technique. The ZrO2 buffer layer effectively protects the superconducting film from the interfacial reaction between the Y-Ba-Cu-O film and the Si substrate during the firing process.
Effect of Compaction on the Superconducting Transition of YBa2Cu3O9-y Compound
Authors: Singh Bhanu Pratap , Agarwal S. K. , Jayaram B. , Nayar R. K. , Nagpal K. C. , Narlikar A. V.
Published: February 2005

A study of the effect of compacting pressure on the superconducting transition of YBa2Cu3O9-y
compound has been systematically carried out. The observed data have been related to the microstructure as observed by scanning electron microscopy and related techniques.
Magnetic Shielding Using High-Tc Superconductor
Authors: Hattori Takeo , Higemoto Nobumasa , Kanazawa Shigeyasu , Kobayashi Matsuo
Published: February 2005

The magnetic shielding has been investigated by measuring magnetic coupling between primary and secondary coils separated by a high-T
c superconductor. The magnetic coupling between primary and secondary coils could not be zero below T
c. This can be explained by the existence of superconductivity related surface current, which flows out from front to rear surface to couple with the secondary coil.