bluuebunny/crossref_metadata_2025 huggingface dataset:
A Very Small Holographic Optical Pick-up Head with a Movable Single-Assembly Optical System
Authors: Kadowaki Shin-ichi , Komma Yoshiaki , Nishino Seiji , Hori Yoshikazu , Makoto Kato Makoto Kato
Published: February 2005

A very small holographic optical pick-up head with a movable single-assembly optical system was proposed. The optical system measures 11 mm(W)×4 mm(D)×4 mm(H) and weighs only 0.34 grams. The basic performance of the optical system mounted on a conventional actuator was demonstrated experimentally.
Phase-Shifting Apodizer of Three or More Portions
Authors: Hideo Ando Hideo Ando
Published: February 2005

This paper is aimed at the problem of attaining increased recording density in optical disks. One way of achieving this is to decrease the size of the optical disk drive's “beam waist spot” (the narrowest portion of the focused area).
The author is presently developing a new type of apodizer structure designed for decreasing the sidelobe intensity and raising the center peak intensity ratio accompanying reduced beam waist spots. The apodizer incorporates a new optical structure and is currently undergoing evaluation.
In developing designs for the new apodizer, the author first used algebraic approximate formulas to obtain a general understanding of the relationship between the intensity distribution at the beam waist spot and each of the relevant parameters. Computer simulation was then used to obtain a detailed performance evaluation.
The evaluation results indicated the following:
(1) The beam waist spot's sidelobe intensity can be reduced by using an optimized apodizer consisting of three or more portions;
(2) Phase-shifting apodizers serve to increase the center peak intensity ratio.
High-Speed Magneto-Optic Disk Drive with Overwriting and Read-Verifying Functions
Authors: Watabe Akinori , Yamada Ichiro , Katoh Kikuji , Kazuki Kudo Kazuki Kudo , Manabu Yamamoto Manabu Yamamoto
Published: February 2005

A 3-beam overwritable magneto-optic (MO) disk drive with instantaneous read-verification is developed for random-access image databases and for high-speed file backup. This drive has two optical heads and three optical beams enabling it to be used with an ISO standard 130-mm diameter MO disk. Write-once optics are used in erasing and writing optical systems, and high-efficiency transmission of laser power yields a data transfer rate of 2.1 MB/s at 5400 rpm.
Stacked Optical Disk Drive for Multimedia Files
Authors: Nakamura Shigeru , Seya Eiichi , Sukeda Hirofumi , Matsumoto Kiyosi , Niihara Toshio , Nihei Hideki , Ichikawa Kouji , Seiichi Mita Seiichi Mita
Published: February 2005

A stacked optical disk drive with multiple optical heads has been developed for large-capacity multimedia files. This drive will be suitable for such applications as a network database through LAN, a picture library Including moving pictures, and an editing machine for broadcast use.
Spatial Resolution and Data Addressing of Frequency Domain Optical Storage Materials in the Near IR Regime
Authors: Ao R. , Jahn S. , Kümmerl L. , R. Weiner R. Weiner , D. Haarer D. Haarer
Published: February 2005

This paper reports recent advances in the study of Frequency domain optical storage (FDOS) based on the photochemical hole-burning (PHB) method. New PHB systems are introduced which operate in the near IR regime and are suitable for the use of semiconductor lasers. Furthermore experiments to determine the spatial resolution of the method are presented. Future applications will also be discussed.
Photochemical Hole Burning of Quinone Derivatives
Authors: Yagyu Eiji , Tetsuya Nishimura Tetsuya Nishimura , Motomu Yoshimura Motomu Yoshimura
Published: February 2005

Photochemical Hole Burning (PHB) has a potential storage density of more than 1011 bits/cm2 using the wavelength dimension. We have investigated increasing the number of holes by additional using the electric field. The holes were measured with high resolution double beam laser spectroscopy. Furthermore, we have demonstrated multiple hole formation using both dimensions, which shows the possibility of the formation of thousands of multiple hole.
Microroughness Measurements on Polished Silicon Wafers
Authors: Abe Takao , Steigmeier Edgar F. , Hagleitner Walter , Pidduck Allan J.
Published: February 2005

Six different techniques i.e. Stylus profilometry, Phase Shift Interferometry (PSI), Scanning Optical Microscopey in Differential Phase Contrast mode (SOM-DPC), Light Scattering Topography (LST), Scanning Tunneling Microscopy (STM) and Atomic Force Microscopy (AFM) have been used for measurements of silicon surface microroughness. Specimens with 4 different surface roughness levels have been prepared by variation of the mechanical or chemical components of a traditional polishing process. At low microroughness, a contradiction is observed between 2 groups: on one hand stylus and PSI, which sample the longer length scales from about 1 micron upwards, and STM and AFM on the other hand, which in this work sampled in the submicron range. The results of SOM-DPC and LST, which sample intermediate roughness scales, coincide with the latter group.
GaAlAs/GaAs Optical Beam Scanner Using Phased Array Waveguides
Authors: Moriki Kazunori , Ohnishi Yoshihumi , Katoh Hisayuki , Inoue Toshihiro , Sakaguchi Takahiro , Iga Takeo Hattori
Published: February 2005

An optical beam scanner integrated with two phased array waveguides is fabricated. The optical beam scanner consists of twin GaAlAs/GaAs waveguides which are integrated with an optical branch for optical power distribution to the twin waveguides. The optical beam can be deflected about 1.0 degree by applying a reverse bias of 10 V to the pn junction in one of the waveguides.
Study on Ferroelectric Transistions of Vinylidene Fluoride/Trifluoroethylene Copolymers by Means of ac Calorimetry Technique
Authors: Ogura Hiroshi , Shimizu Toshihiro , Motoyama Hideki , Chiba Moyuru Ochiai
Published: February 2005

By means of the ac calorimetry technique, the ferroelectric transition behavior of vinylidene fluoride/trifiuoroethylene (VDF/TrFE) copolymers was investigated. The data from ac calorimetry were compared with those from adiabatic calorimetry to elucidate the orders of the transition. From the comparison, it was clarified that the ferroelectric transitions of copolymers containing 73 and 65 mol% VDF are of the first order, while the copolymer with 55 mol% VDF shows the second-order character. These results were qualitatively explained using a simple model for rotational transitions. Throughout this work, an important feature of ac calorimetry, i.e., the exclusion of the contribution of latent heat, was confirmed in the measurements of PE and VDF/TrFE copolymers.
Experimental Characteristics of Electret Generator, Using Polymer Film Electrets
Authors: Yasufusa Tada Yasufusa Tada
Published: February 2005

An experimental electret generator has been developed to examine its operating theory. Although the generator is essentially a simplified version of Jefimenko's electret generator, it has none of the shortcomings of his generator. Since the electret used in our generator is a Teflon FEP film electret retaining stable homocharge, it does not have to be shielded. Our generator is of the single-ended-output type; therefore the electret need not have mechanical strength. The generator is a typical parametric machine which has the simplest structure. The fundamental electrical characteristics of the generator are derived experimentally. The experimental characteristics agree well with the theoretical ones. The maximum power obtained when the revolution number equaled 5000 rpm was \fallingdotseq1.02 mW.
Monte Carlo Modelling of Ion-Beam-Assisted-Deposition: Application to Diamondlike Carbon
Authors: Fran\ccois Rossi Fran\ccois Rossi , Bernard Andre Bernard Andre
Published: February 2005

We have performed a Monte Carlo simulation of the growth of a carbon film under ion bombardment, taking into account a preferential displacement of atoms in the film depending on their hybridization state. The size of the cascade and the number of displacements in the solid are calculated depending on the concentration in diamond-type chemical bonds (sp3) or graphite-type chemical bonds (sp2). These values are used in a Monte Carlo code which calculates the local changes in concentration in sp3 sites and sp2 sites due to the effect of the cascades. The effect of the ion energy and the ratio between ions and atoms fluxes is studied. A comparison is made with experimental results where diamondlike carbon films are obtained under Ar+ and Xe+ irradiations. Good qualitative agreement is obtained between the properties of the film measured and the results of the model.
Electronic Properties of GaAs Thin Film Deposited on Silica Substrate by RF Sputtering
Authors: Tsuji Seiji , Iri Eiji , Takakura Hideyuki
Published: February 2005

Electrical conductivity on GaAs thin film deposited by RF sputtering was measured, and temperature dependence was analyzed. The film has very low conductivity in the range of 10-4 Ω-1 cm-1, and the activation energy of the conductivity is 0.67 eV. The conductivity is strongly limited by the high density of deep oxygen impurity as well as by grain boundaries.
A Study on the Scalar Wave Equation for Nonlinear Surface Acoustic Wave Distortion
Authors: Yamanouchi Yasuo Cho
Published: February 2005

A new definition and interpretation of nonlinear parameter β and scalar potential φ of the one-dimensional phenomenological nonlinear scalar equation of surface acoustic waves (SAW) are proposed. This definition made it possible to solve the problem of SAW waveform distortion caused by its nonlinearity. Finally, the discontinuity length of the SAW propagating along the X-axis on 128°-rotated Y-cut LiNbO3 was obtained by means of this definition.
Properties of Photosensor with Amorphous Si:H/SiOx:H Double-Layer Structure
Authors: Haga Koichi , Murakami Akishige , Adachi Kazuhiko , Watanabe Masafumi Kumano
Published: February 2005

A new amorphous silicon photosensor with glass/Cr/a-Si:H/a-SiO
x
:H/ITO structure was prepared. Initially, the photoresponse of this structure to a light pulse is about 750 times slower than that of the photosensor with the inverse (glass/ITO/a-SiO
x
:H/a-Si:H/Cr) structure. The X-ray photoemission spectra show that the a-SiO
x
:H surface is additionally oxidized during deposition of the ITO electrode. A fast response with a rise time of less than 1 ms can be obtained by treating the a-SiO
x
:H surface with boron plasma or depositing the boron-doped a-SiO
x
:H layer onto the undoped a-SiO
x
:H layer before the ITO deposition.
Analysis of Oxidation-Enhanced/Retarded Diffusions of Substitutional Impurities in Silicon
Authors: Takahisa Okino Takahisa Okino
Published: February 2005

Oxidation-enhanced/retarded diffusions of substitutional impurities in Si(OED/ORD) are generally expressed by well-known equations consisting of self-interstitial and vacancy concentrations (I and V). From the asymptotic forms of the formal solutions of those equations, an approximate relation between I and V was obtained in the time range of interest. Identifying this approximate relation with that of local equilibrium between I and V gave a simple method by which to obtain mathematically self-consistent solutions of OED and ORD equations. Consequently, I and V were obtained as functions of the diffusion time. The fractional components of the interstitialcy mechanism for OED of P and ORD of Sb (d
1
P and d
1
Sb) were obtained, with the first results being independent of time, i.e., d
1
P=0.93 and d
1
Sb=0.029 at 1100°C.
Transient Light-Induced ESR Investigations of the Role of Hydrogen in the Stability of a-Si:H
Authors: Saleh Zaki M. , Tarui Hisaki , Ninomiya Kunimoto , Takahama Tsuyoshi , Nakashima Yukio , Nakamura Noboru , Haku Hisao , Wakisaka Kenichiro , Tanaka Makoto , Tsuda Shinya , Nakano Shoichi , Yasuo Kishi Yasuo Kishi , Yukinori Kuwano Yukinori Kuwano
Published: February 2005

Transient light-induced electron spin resonance (LESR) at 120 K has been used to investigate the light-soaking behaviors and the role of hydrogen in the stability of a-Si:H through changes in the lineshape. Dramatic changes occur in the LESR lineshape upon prolonged light-soaking, and we suggest that hydrogen defects (Si-H2 or clustered Si-H bonds) play an important role in these changes. A microscopic explanation of the possible optical excitations and defect conversion processes leading to these changes during the LESR experiment is proposed.
Elastic Anomaly of YBa2Cu3O7-δ at the Superconducting Transition
Authors: R. Abd-Shukor R. Abd-Shukor
Published: February 2005

The relative change in shear ultrasonic velocity in single phased YBa2Cu3O7-δ (δ=0.02) polycrystalline high T
c superconductor has been determined using the phase detection technique. The shear velocity was found to increase at a greater rate below the zero-resistance temperature (T
c=90 K) and showed a slope discontinuity (d/dT[Δvs/vs]) of 84 ppm/K. Using experimental value of the discontinuity in the specific heat at T
c, the second shear-stress-derivatives of the transition temperature (∂2
T
c/∂σ2) is estimated to be 0.06 K/(kbar2).
The Anisotropy of Transport Critical Current Densities in Tl2Ba2Ca2Cu3Ox Thin Films under Magnetic Fields up to 20 T
Authors: Nabatame Toshihide , Watanabe Kazuo , Awaji Satoshi , Saito Yukio , Aihara Katsuzo , Tomoichi Kamo Tomoichi Kamo , Shin-Pei Matsuda Shin-Pei Matsuda
Published: February 2005

The anisotropy of transport critical current densities (J
c) in Tl2Ba2Ca2Cu3O
x
thin film was measured resistively at 77 K under magnetic fields up to 20 T. When the magnetic field was applied parallel to the a-b plane (a-b plane//B), the values of J
c were 1.2×104 and 1.5×103 A/cm2 at 5 and 16 T, respectively. On the other hand, in fields perpendicular to the a-b plane (a-b plane⊥B), J
c decreased drastically in the low field region. The irreversible magnetic field (B
c2
*) values for (a-b plane//B) and (a-b plane⊥B) were 22.0 and 0.89 T, respectively. The pinning force density (F
p=J
c×B) can be described by the Kramer scaling law, F
p/F
p
max=3.4×b
1/2(1-b)2, where b (B/B
c2
*) is the reduced field. From measuring the angular dependence of J
c, as incident angle (θ) increased, J
c decreased drastically.
Liquid-Nitrogen-Cooled Dry Etching of YBaCuO Thin Films
Authors: Sato Hiroshi , Akoh Hiroshi , Nishihara Keirou , Masahiro Aoyagi Masahiro Aoyagi , Susumu Takada Susumu Takada
Published: February 2005

A new dry etching method has been developed for patterning YBaCuO thin films with less damage, wherein samples are cooled by liquid nitrogen. It is found that the critical current density J
c of films etched by this cooling method is significantly improved, more than one order of magnitude higher than that for the films etched at 5°C. Furthermore, it is found that this technique causes less damage to the surface of the YBaCuO films, compared to the etching at 5°C. This result suggests that the dry etching process with liquid nitrogen cooling is a promising method for the fabrication of high-T
c superconducting electronic devices of small dimensions.
Photochromic Property of Triphenylformazan Films Prepared by Vacuum Evaporation
Authors: Ito Kohzo , Shimomura Masaki , Hiroko Kyotani Hiroko Kyotani , Yoshikazu Tanabe Yoshikazu Tanabe
Published: February 2005

Morphology and the photochromic property were studied comparatively for triphenylformazan (TPF) films prepared by vacuum deposition on glass substrates at -150°C (S-LT) and room temperature (S-RT). The S-LT sample showed photochromic change from violet to pale blue whereas the S-RT sample was insensitive to the irradiation of visible light. Microscopic observation indicated that rapid cooling would impede the crystallization of TPF molecules on the substrate and thereby yield amorphous films with conformational change of the molecules.
Determination of a Track's Edge by Differential Power Spectrum
Authors: Indeck Ronald S. , Guo Mian Guo Mian , Marcel W. Muller Marcel W. Muller
Published: February 2005

We show experimentally that the transverse edge of recorded data can be determined by spatially differentiating the readback power spectrum with respect to the displacement of the recording head. This was accomplished using straightforward signal processing described here as the differential power spectrum. This technique can be applied to data tracks having pseudorandom data even in systems not possessing guard bands. We describe a multi-element head structure which may be used to exploit this phenomenon to realize a new continuously monitored track following servo system.
Thermally Addressed Polymer Dispersed Liquid Crystal Displays
Authors: Yamaguchi Rumiko , Hiroshi Ookawara Hiroshi Ookawara , Susumu Sato Susumu Sato
Published: February 2005

Thermally addressed liquid crystal displays are prepared using polymer dispersed liquid crystal films which have highly transparent memory states. Thermal images can be written in positive and negative modes using an yttrium-aluminum-garnet laser beam, and local erasure and rewriting are possible in both modes. A thermal printer head can also be used to write.
Quantitative Analysis of Surface Contaminations on Si Wafers by Total Reflection X-Ray Fluorescence
Authors: Kondo Hideyuki , Ryuta Jiro , Morita Etsuro , Yoshimi Toshihiro , Yasushi Shimanuki Yasushi Shimanuki
Published: February 2005

A total reflection X-ray fluorescence (TRXRF) technique has been recently used to analyze metal contaminations on Si wafers. In this work, microdrop-contaminated Si wafers are used to make the calibration curves. Metal impurities in these wafers are shown to be condensed in a very small area near the center of the dropped area. To make the calibration curve, a relationship is derived between the intensity of the characteristic X-ray from metal impurities in the condensed area and that from the impurities uniformly distributed over the wafer surface. On the basis of this relationship, calibration curves for Fe, Ni, Cu and Zn are obtained.
Helium Beam Diffractive Scattering from an Ordered Layer of Carbon on a W(110) Surface
Authors: Yamamoto Shigehiko , Tanuma Tatsuya Miyake
Published: February 2005

Diffractive scattering of a He supersonic beam has been observed from a W(110) surface covered with carbon. The beams, of [1̄11] and [001] azimuthal incidence angles, show diffraction peaks resulting from an ordered structure which has doubly spaced lattice spacings of the substrate W(110), suggesting a (2×2) structure of a quarter monolayer of adsorbed carbon.
A Novel Preparation Method of Organic Microcrystals
Authors: Kasai Hitoshi , Nalwa Hari Singh , Oikawa Hidetoshi , Okada Shuji , Matsuda Hiro , Minami Nobutsugu , Kakuta Atsushi , Ono Katsumichi , Mukoh Akio , Hachiro Nakanishi Hachiro Nakanishi
Published: February 2005

Organic microcrystals ranging from several tens nm to µm in size of several chromophores were successfully prepared by simply dispersing ethanol solutions of compounds into stirred water, i.e. by a reprecipitation method. The size of microcrystals was found to depend on concentration of ethanol solutions, dispersing conditions, temperature and so on.
Phase Shift of Neutrons in Magnetic Domains Observed by Interferometry
Authors: Nakatani Shinichiro , Tomimitsu Hiroshi , Kikuta Toshio Takahashi
Published: February 2005

Intensity variations of outgoing beams from a perfect crystal neutron interferometer were measured using an Fe-3%Si crystal and an Al plate as phase shifters. The inside of the Fe-3%Si crystal was partitioned with 180° magnetic domain walls whose images were clearly observed by neutron topography. From the analysis of intensity oscillations the magnetic forward scattering length of Fe atoms in the crystal was estimated as 5.56×10-13 cm, which is very close to the established value, 5.98×10-13 cm. This result indicates that the spontaneous magnetization in each domain is almost saturated.
Epitaxial Growth of Metal(CoSi2)/Insulator(CaF2) Nanometer-Thick Layered Structure on Si(111)
Authors: Watanabe Masahiro , Muratake Shigeki , Fujimoto Hiromasa , Sakamori Shigenori , Masahiro Asada Masahiro Asada , Shigehisa Arai Shigehisa Arai
Published: February 2005

Epitaxial growth of a metal(CoSi2)/insulator(CaF2) nanometer-thick layered structure on Si(111) was demonstrated. An epitaxial CoSi2 layer on CaF2 was obtained by the two-step growth technique, i.e., solid phase epitaxy with the epitaxial Si layer grown in the first step and Co deposited in the second step. This technique was shown to be effective in avoiding the Co agglomeration on the CaF2 layer observed in the co-evaporation of Si and Co. An epitaxial CaF2 layer was formed on CoSi2/CaF2 at low substrate temperature (450°C) with a partially ionized and accelerated CaF2 beam, to avoid Co agglomeration in the CoSi2/CaF2 underlayer as well. Obtained results showed a single-crystalline nature in reflection high-energy electron diffraction (RHEED) and transmission electron microscopy (TEM) observations.
Second-Harmonic Generation in Poly(vinylidene fluoride) Films Prepared by Vapor Deposition under an Electric Field
Authors: Kubono Atsushi , Kitoh Tetsuji , Kajikawa Kotaro , Umemoto Susumu , Takezoe Hideo , Atsuo Fukuda Atsuo Fukuda , Norimasa Okui Norimasa Okui
Published: February 2005

Second-harmonic generation (SHG) revealed the dipole orientation of poly(vinylidene fluoride) (PVDF) thin films prepared by vapor deposition in the presence of an electric field along the substrate surface. The dipole alignment was confirmed for the substrate temperatures between -130°C and 100°C under an electric field of 16 MV/m. The degree of dipole orientation estimated from the ratio of nonlinear susceptibility components depended on the deposition conditions such as the substrate temperature and the field strength. Thermal stability of the poled structure was found to be much better than that obtained by postpoling.
Optical Humidity Sensor with a Fast Response Time Using Dye-Adsorbed Langmuir-Blodgett Films
Authors: Morisawa Masayuki , Hidenori Uematsu Hidenori Uematsu , Shinzo Muto Shinzo Muto
Published: February 2005

When Langmuir-Blodgett (LB) films made of multilayered stearic acid or hematoporphyrin containing a phenol-red dye were exposed to a moist environment, changes in the absorption coefficient occurred. This is due to an ionization reaction of the dye molecules dispersed into these LB films. The optical humidity sensors which were simply constructed using these dye-adsorbed LB films operated with good reproducibility and a very fast response time.
Intensity Fluctuations in Multimode Lasers with Spatial Hole Burning
Authors: Otsuka Kenju , Georgiou Miltos , Mandel Paul
Published: February 2005

The intensity fluctuations in multimode lasers with spatial hole burning are investigated. We give experimental evidence for a self-organized collective behavior resulting from the cross saturation dynamics of spatially hole-burned lasers, in which each mode is characterized by N relaxation oscillation frequencies ω
l
(l=1, 2, 3,···, N; N: number of oscillating modes), while the total output exhibits a unique relaxation oscillation at the highest frequency in ω
l
which coincides with that in a single mode laser.
Catalytic Precracking of Amino-As in Metalorganic Molecular-Beam Epitaxy of GaAs
Authors: Koui Tomoaki , Suemune Ikuo , Miyakoshi Kaoru , Kazuyuki Fujii Kazuyuki Fujii , Masamichi Yamanishi Masamichi Yamanishi
Published: February 2005

Precracking of an As source employing the catalytic effect of GaAs is proposed for the growth of GaAs in metalorganic molecular-beam epitaxy. The As source used was an amino-As, tris-dimethylamino-arsenic {TDMAAs, As[N(CH3)2]3}. The enhancement of the growth rate was observed for an optimum combination of the substrate temperature and the cracking temperature. The mechanism of the growth enhancement was studied by means of quadrupole mass spectrometry. It is shown that the intermediate As species of the amino-As play a prominent role in growth enhancement.
Zero-Bias Resistance Peak in Oxide-Semiconductor Junctions
Authors: Tamura Kazuaki , Miyakawa Nobuaki , Shimada Daisuke , Akahane Takashi , Nobuo Tsuda Nobuo Tsuda
Published: February 2005

A zero-bias resistance peak appeared in the tunneling resistance curve of Bi-cuprates, Na0.89WO3 and ReO3, contacted with GaAs or SnO2-x
. Therefore the peak is not inherent to high-T
c superconductors and may not be relevant to the electronic properties in the bulk.
Improvement of Reproducibility of High Transport Jc for Bi2Sr2CaCu2Oy/Ag Tapes by Controlling Bi Content
Authors: Shimoyama Jun-ichi , Tomita Naruaki , Morimoto Takeshi , Kitaguchi Hitoshi , Kumakura Hiroaki , Togano Kazumasa , Maeda Hiroshi , Nomura Katsumi , Seido Masahiro
Published: February 2005

A new method to obtain high J
c Bi-2212/Ag tapes with high reproducibility was developed. Melt-solidifying with Bi2Al4O9 is found to be an effective method for suppressing the vaporization of bismuth oxide during the high-temperature heat treatment. By application of this method, the homogeneity of the microstructure of the Bi-2212 layer was improved considerably due to a decrease of the Bi-poor phase, (Sr, Ca)-Cu-O. The reproducibility of J
c values was also improved corresponding to the microstructure, and J
c maintained more than 1×105 A/cm2 at 4.2 K in 7 T even for a 1 m tape.
Atom Intensity Variation in the Scanning Tunneling Microscope Image of Mixed Crystals of Transition Metal Dichalcogenides
Authors: Mori Tomohiko , Koichiro Saiki Koichiro Saiki , Atsushi Koma Atsushi Koma
Published: February 2005

Two kinds of mixed crystals of transition metal dichalcogenides (TX2), Mo1-X
W
X
Se2 and MoSe2-Y
S
Y
, have been studied using the scanning tunneling microscope (STM). Both mixed crystals have shown atom intensity variation in STM images, whereas very uniform atom images have been observed for pure MoSe2. This indicates that both surface and subsurface atom substitutions induce atom intensity variations. The observed features can be explained qualitatively in terms of their band structures.
Reappraisal of Si-Interlayer-Induced Change of Band Discontinuity as GaAs-AlAs Heterointerface Taking Account of Delta-Doping
Authors: Akazawa Masamichi , Hasegawa Hideki , Tomozawa Hidemasa , Fujikura Hajime
Published: February 2005

The title should read:Reappraisal of Si-Interlayer-Induced Change of Band Discontinuity at GaAs-AlAs Heterointerface Taking Account of Delta-Doping
Doping Properties of GaAs Selective Epilayers Grown by Atmospheric-Pressure Metalorganic Chemical Vapor Deposition
Authors: Yamaguchi Ko-ichi , Shigeki Kishida Shigeki Kishida , Kotaro Okamoto Kotaro Okamoto
Published: February 2005

Selective epitaxial growth of Si- and Zn-doped GaAs was carried out by atmospheric-pressure metalorganic chemical vapor deposition. The carrier concentration of the selective epilayers changed from that of the uniformly grown epilayers: decrease in Si-doping efficiency and increase in Zn-doping efficiency in selective epitaxial growth. The main cause for these phenomena is the lateral supply of AsH3 from SiO2-mask areas to GaAs-window areas, which is induced by the selective decomposition of AsH3.
Determination of the Energy Distribution of Grain Boundary Traps in Polycrystalline Silicon Films
Authors: Ichiro Yamamoto Ichiro Yamamoto , Hiroshi Kuwano Hiroshi Kuwano
Published: February 2005

The energy distribution of grain boundary traps in polycrystalline silicon films is determined from the activation energy of resistivity measured as a function of boron and phosphorus doping concentrations. The energy distribution is expressed as the Gaussian distribution with its center located at 0.10 eV under the midgap and the standard deviation of 0.18 eV.
Phosphine Doping Effects in the Plasma Deposition of Polycrystalline Silicon Films
Authors: Kakinuma Hiroaki , Mikio Mohri Mikio Mohri , Taiji Tsuruoka Taiji Tsuruoka
Published: February 2005

The effects of phosphine doping on the electronic and structural properties of polycrystalline silicon (poly-Si) films prepared by plasma chemical vapour deposition using SiF4/SiH4/H2 gases have been investigated. With increasing doping ratio, the conductivity rapidly increases and takes a maximum value of 80 S·cm-1 at [PH3]/[SiH4](=γ)∼1.7×10-2, while it decreases at larger doping ratios. This change is found to be caused mainly by the change in the carrier density, by Hall measurements. X-ray diffraction and transmission electron microscopy indicate that this electronic change is associated with the change in the preferred orientation of grains from <110> to <111> with a slight decrease in grain size, and the structural change from crystalline to amorphouslike with increasing γ.
Flux Pinning Characteristics in 180 MeV Cu11+-Irradiated Bi2Sr2CaCu2Ox
Authors: Kumakura Hiroaki , Kitaguchi Hitoshi , Togano Kazumasa , Maeda Hiroshi , Shimoyama Jun-ichi , Okayasu Satoru , Kazumata Yukio
Published: February 2005

We investigated the effect of Cu11+ irradiation on the flux pinning in c-axis grain-oriented Bi2Sr2CaCu2O
x
by means of the d.c. magnetization method. Irradiation significantly enhanced both hysteresis of d.c. magnetization and the irreversibility field at temperatures up to 60 K. Flux creep was suppressed by the irradiation. However, the apparent pinning potential energy U
0 of irradiated samples was still small. The U
0 values of irradiated and nonirradiated samples were 14 meV and 8 meV in 4 T at 4.2 K and 40 meV and 15 meV in 0.2 T at 41.8 K, respectively.
Optical Anisotropy of Vacancy-Ordered Ga2Se3 Grown by Molecular Beam Epitaxy
Authors: Okamoto Tamotsu , Kojima Nobuaki , Yamada Akira , Konagai Makoto , Takahashi Kiyoshi , Nakamura Yoshio , Nittono Osamu
Published: February 2005

Optical anisotropy of the vacancy-ordered Ga2Se3 grown on (100)GaP has been investigated. The electron-diffraction studies revealed that the vacancy-ordered superstructure was predominantly formed in the [011] direction when the film was grown with a VI/III ratio of 150. From the transmission spectra for light polarized toward [011] and [011̄], it is found that a difference in the absorption coefficients of the two polarized lights is more than 104 cm-1 at a wavelength of around 525 nm, and that the vacancy-ordered Ga2Se3 behaves like a polarizer in the selected wavelength range.
Image Recording with Ferroelectric Film (I)
Authors: Guo Yufeng , Hoshino Katsuyoshi , Kokado Jun-ichi Hanna
Published: February 2005

A novel image recording system with memory effect is proposed, which utilizes unique corona charging characteristics of thin films of an organic ferroelectric material, a copolymer of vinylidene fluoride and tetrafluoroethylene (poly(VDF-TFE)). Using this recording system, a high-quality image was formed through the following successive processes: 1) uniform poling of the poly(VDF-TFE) film by corona charging, 2) image-wise depolarization of dipoles by a thermal pulse (latent image formation), and 3) uniform corona charging to attain the contrast potential for toner development (visualization of latent image). The fundamentals of the imaging process are also discussed in terms of the properties of the films.
Relaxation Process of the Thermal Strain in the GaN/α-Al2O3 Heterostructure and Determination of the Intrinsic Lattice Constants of GaN Free from the Strain
Authors: Detchprohm Theeradetch , Hiramatsu Kazumasa , Kenji Itoh Kenji Itoh , Isamu Akasaki Isamu Akasaki
Published: February 2005

The relaxation process of the thermal strain in a GaN film due to the thermal expansion coefficient difference in the GaN(0001)/α-Al2O3(0001) heterostructure is studied by varying the film thickness of GaN in a wide range from 1 to 1200 µm. The lattice constant c has a large value of 5.191 Å at a film thickness less than a few microns, while it decreases to about 150 µm, and becomes constant above 150 µm, indicating that the strain is almost completely relaxed. The intrinsic lattice constants of wurtzite GaN free from the strain, a
0 and c
0, are determined to be 3.1892±0.0009 and 5.1850±0.0005 Å, respectively.
High-Quality InGaN Films Grown on GaN Films
Authors: Shuji Nakamura Shuji Nakamura , Takashi Mukai Takashi Mukai
Published: February 2005

InGaN films were grown on GaN films with a high indium source flow rate and high growth temperatures between 780°C and 830°C. Strong and sharp band-edge (BE) emissions between 400 nm and 445 nm were observed, while deep-level emissions were barely observed in photoluminescence (PL) measurements at room temperature. The full width at half-maximum (FWHM) of the BE emissions was about 70 meV. The FWHM of the double-crystal X-ray rocking curve (XRC) from the InGaN films was about 8 minutes. This value of FWHM was the smallest one ever reported for InGaN films, and was almost the same as that of the GaN films which were used as the substrate.
Electrical Transport and Superconductivity in the Au-Bi2Sr1.8Ca1.2Cu2Oy Composite System
Authors: Lin Wen-Yuan , Chen Juhn-Jong Lin
Published: February 2005

We have measured the resistivity ρ of the Au-Bi2Sr1.8Ca1.2Cu2O
y
composite system with Au volume fraction p
Au ranging from 0.00 to 1.00. We find, for the samples with p
Au≤0.4, that the addition of Au does not disturb the superconducting transition temperature of Bi2Sr1.8Ca1.2Cu2O
y
. For the samples with p
Au≥0.6, no zero-resistivity state is observed. The variation of ρ(300 K) with p
Au indicates a three-dimensional percolating Au matrix occurring at p
Au≈0.18.
Size Dependence of Response Time of Volume Instability in Conducting Polymer Gel
Authors: Morita Shigenori , Shakuda Shuzo , Ryu-ichi Sugimoto Ryu-ichi Sugimoto , Katsumi Yoshino Katsumi Yoshino
Published: February 2005

The expansion time of poly(3-alkylthiophene) gel depends on its size. The time increases linearly with increasing thickness as well as side length. The expansion of poly(3-alkylthiophene) gel is interpreted by the diffusion of solvent molecule into gel as the first step and then the diffusion of gel network into solution. The solvent molecule diffusion and the gel network diffusion depend on the thickness and the side length, respectively. The gel network diffusion velocity is much higher than the solvent diffusion. The shrinkage time upon doping also increases linearly with increasing side length.
Fabrication of Bi2Sr2CaCu2Ox High Tc Superconducting Film with H2O Assisted Metalorganic Chemical Vapor Deposition
Authors: Nishikawa Tsuyoshi , Satoh Mitsuru , Kunio Asada Kunio Asada , Takuo Sugano Takuo Sugano
Published: February 2005

With the objective of the deposition of Bi2Sr2CaCu2O
x
(BSCCO(2212)) films at low temperature, the metalorganic chemical vapor deposition (MOCVD) has been carried out and c-axis oriented BSCCO(2212) films on MgO(001) substrates were obtained at 550°C and 600°C. When water vapor was added into the reactor, the crystallization of deposited films changed in relation to the partial pressure of water vapor. The more H2O was supplied, the less BSCCO(2212) crystal tended to be formed at 600°C, and the opposite tendency was found at 550°C.
A Second-Harmonic Generation Study Applied to Sulfur Passivation and Photochemical Washing of GaAs Surfaces
Authors: Yamada Chikashi , Takahiro Kimura Takahiro Kimura , Peter Fuqua Peter Fuqua
Published: February 2005

Second-harmonic generation (SHG) method was applied to a real-time study of the passivation process using Na2S and photochemical washing of GaAs (100) surfaces. In these processes a remarkable similarity between the intensity changes of SHG and photoluminescence (PL) which was observed simultaneously, was observed. Possible causes of the SHG enhancement, electron-hole pair formation, interband transition, and still controversial model of Fermi level pinning, were examined.
Effect of Size of Superconductor on Estimation of Critical Current Density Using AC Inductive Method
Authors: Ohtani Nozomu , Otabe Edmund Soji , Ni Teruo Matsushita
Published: February 2005

Applicability of the ac inductive measuring method for estimation of the critical current density, J
c, in superconductors of relatively small size is theoretically investigated in terms of the Campbell model for pinning force density vs the displacement of fluxoids. It is shown that J
c is significantly overestimated by the conventional method due to reversible fluxoid motion for superconductors comparable to or smaller than Campbell's ac penetration depth, λ0
′. Only the recently proposed analysis of imaginary ac susceptibility yields relatively accurate values even for superconductors much smaller than λ0
′.
Preparation of ZBLAN Fluoride Glass Particles by Chemical Vapor Deposition Process
Authors: Nishida Yoshiki , Fujiura Kazuo , Sato Hirotsugu , Sugawara Shungo , Kenji Kobayashi Kenji Kobayashi , Shiro Takahashi Shiro Takahashi
Published: February 2005

We have successfully synthesized NaF-containing ZrF4-based fluoride glass (ZrF4-BaF2-NaF) (ZrF4-BaF2-LaF3-AlF3-NaF) particles by the chemical vapor deposition (CVD) process. In this process, Na β-diketonate (Na(ppm)) was used for the Na source. Differential scanning calorimetry (DSC) results suggested that NaF should be contained uniformly in the glass particles. The thermal properties of the glass which was prepared in this experiment were almost the same as those glass prepared by the conventional melt-casting method.
Role of Hydrogen in Atomic Layer Epitaxy of GaAs Using GaCl3
Authors: Kobayashi Ryuji , Ishikawa Katsumi , Satoru Narahara Satoru Narahara , Fumio Hasegawa Fumio Hasegawa
Published: February 2005

Effects of hydrogen on chloride atomic layer epitaxy (ALE) of GaAs using GaCl3 were studied using He carrier gas and solid arsenic. It was found that some gallium chloride complexes adsorb on the GaAs surface even during H2 purging, and the desorption of Cl atoms only occurs when arsenic is supplied as AsH3 or arsenic vapor with H2. However, since partial pressure of GaCl3 is quite different in ordinary chloride ALE, those results may not be directly applied to ordinary chloride ALE using GaCl.
Estimation of the Surface State Density of N-Type (111)A GaAs Grown Using Molecular Beam Epitaxy
Authors: Lovell David R. , Takebe Toshihiko , Yamamoto Teiji , Inai Makoto , Kikuo Kobayashi Kikuo Kobayashi , Toshihide Watanabe Toshihide Watanabe
Published: February 2005

The Schottky barrier heights of Pt, Ni and Cr on Si doped n-type GaAs, grown by molecular beam epitaxy on (111)A GaAs which was misoriented by 5° toward [100], have been measured using capacitance-voltage and current-voltage techniques. The contacts were formed by metal evaporation onto GaAs which was cleaned with dilute H3PO4. By fitting a straight line to the Schottky barrier height versus metal work function data, the surface state density of the n-type epitaxial GaAs is estimated to be 4.57×1013 cm-2·eV-1.
Properties of Titanium Layers Deposited by Collimation Sputtering
Authors: Hara Tohru , Chen Tomonori Nomura
Published: February 2005

Properties of titanium (Ti) films deposited by collimation sputtering are studied. In Ti film deposition at the 0.5 µm ohmic contact area (aspect ratio: 3.6), conformality, y/x, defined by the thickness on the bottom, y, to the surface, x, is as low as 6% in conventional sputtering. However, it can be improved to 21% by employing collimation sputtering. Strongly (002)-oriented Ti film is deposited by conventional sputtering. Weakly (002)- and (011)-oriented grains, however, are grown in collimation film. with annealing at 650°C of the Ti film deposited on Si, different solid phase silicidation reactions occur at the Ti/Si. That is, metastable C49 TiSi2 grains are grown in conventional Ti film at 625-650°C. In collimation film, C54 TiSi2 grains are preferentially grown at this temperature. This result indicates the formation of a stable C54 TiSi2 layer with lower sheet resistance.
Resonance Photoemission Spectroscopy of Mn2As, Cr2As and Fe2As
Authors: Matsushita Tomohiro , Kimura Akio , Daimon Hiroshi , Suga Shigemasa , Kanomata Takeshi , Kaneko Takejiro
Published: February 2005

Synchrotron radiation photoemission spectra are measured for antiferromagnetic Mn2As, Cr2As and Fe2As in the 3p core excitation region. It is found from the constant initial state (CIS) spectra that the 3d states in Mn2As provide many different spectral features from those of Cr2As and Fe2As. The experimental results are discussed in comparison with the results of recent band calculations as well as with the experimental results of Mn2Sb and MnAlGe.
Fabrication of Porous TiO2 Films Using Two-Step Replication of Microstructure of Anodic Alumina
Authors: Masuda Hideki , Kazuyuki Nishio Kazuyuki Nishio , Nobuyoshi Baba Nobuyoshi Baba
Published: February 2005

Microporous TiO2 films were fabricated using a two-step replicating process, in which porous anodic alumina was used as a template. The TiO2 films prepared from a TiO2 sol solution had straight micropores of high aspect ratio, and the distribution of the pore diameter was very sharp. Change due to postheating treatment of as-prepared TiO2 films was examined by electron diffraction analysis and scanning electron microscopic observation.
In Situ Observations of the Growth Process of C-Axis-Oriented Bi2Sr2Ca1Cu2Ox Superconducting Phase
Authors: Hasebe Tsuginori , Tanaka Yoshiaki , Yanagiya Tomoyuki , Asano Toshihisa , Fukutomi Masao , MAEDA Hiroshi
Published: February 2005

The growth process of the highly oriented microstructure of Bi2Sr2Ca1Cu2O
x
(2212) crystalline phase has been studied by a method of in situ high-temperature microscopy. The melting state of calcined powders and growth of 2212 crystals on an Ag foil substrate have been directly observed by an optical microscope. The 2212 calcined powders are resolved into a mixed phase at 890°C, which consists of liquid, Bi-free crystalline and Cu-free crystalline phase. The composition of the liquid phase is closer to Bi2Sr2Cu1O
x
than to Bi2Sr2Ca1Cu2O
x
of the starting material. The plate-shaped Bi2Sr2Ca1Cu2O
x
crystals are grown with the a-b planes parallel to the free surface of molten samples.
Dual Wavelength Electro-Optical Bistability in an Asymmetric Self-Electro-Optic Effect Device
Authors: Kawashima Kenji , Fujiwara Kenzo , Sano Kikuo Kobayashi
Published: February 2005

We have demonstrated bistable operation of an asymmetric self-electro-optic effect device (A-SEED) which consists of a GaAs/AlAs superlattice and an InGaAs/AlGaAs multiple quantum well. The A-SEED is driven by two illuminations with widely separated wavelengths, one of which is transparent to the GaAs substrate. Advantages of the A-SEED for applications to optically bistable transmission devices are discussed with emphasis on negligible crosstalk between the signal beam and the control beam.
Proximity Effect in NbN-La1-xCaxMnOz Magnetic Oxide-NbN Coplanar-Type Junction
Authors: Kozono Yuzoo , Ohno Toshiyuki , Masahiro Kasai Masahiro Kasai , Yooko Kanke Yooko Kanke
Published: February 2005

A coplanar-type NbN-La1-x
Ca
x
MnO
z
(x=0.23)-NbN junction was fabricated on MgO(100) single-crystal substrates by means of electron-beam lithography and the argon ion-beam milling method, and the junction characteristics were measured. The spacing between the NbN electrodes is 0.25 µm and the junction width is 100 µm. Nonlinearity in the current-voltage characteristics is observed below 6 K, and supercurrent through the junction is observed below 3 K. These results indicate the possibility of a novel proximity effect in the junctions of the combination of NbN and La1-x
Ca
x
MnO
z
as well as for that of Y1Ba2Cu3O
y
and La1-x
Ca
x
MnO
z
.
Ion Implantation into Polypropylene
Authors: \vSvor\vcík Václav , Rybka Vladimír , Volka Karel , Hnatowicz Vladimír , Kvítek Ji\vrí , Seidl Pavel
Published: February 2005

The effects of F+ion implantation on the composition and the structure of oriented polypropylene were studied by optical methods and the Rutherford backscattering (RBS) technique. From the measurement of the contact angle, it was found that the polar component of the surface energy increases with increasing ion fluence. The spectroscopic measurements confirmed the formation of conjugated double bonds and C=O groups in the implanted polypropylene, but not the presence of C-F groups. The oxygen contamination of the polypropylene surface layer was observed in RBS measurements.
Effect of Thermal Treatments on Fe3+-Related Absorption and Infrared Photoluminescence Spectra of CuGaS2
Authors: Li Xiang-Ji , Kudo Yuki , Matsuda Seisuke , Igor Aksenov Igor Aksenov , Katsuaki Sato Katsuaki Sato
Published: February 2005

Optical absorption and infrared photoluminescence spectra of CuGaS2 single crystals, grown by chemical vapour transport and annealed in various atmospheres (under vacuum, S-vapour, and in the presence of Cu and Ga), have been studied in order to gain information on the positions of residual iron ions in the crystal lattice of CuGaS2. Having analysed the results obtained, we have proven that Fe ions substitute both Cu and Al sites in the crystel lattice, forming two types of defects, i.e., FeCu and FeGa, the former being responsible for the infrared photoluminescence and the latter causing the green colouration of the crystals.
Effects of Deposition Temperature on Strain in Polycrystalline SiC Films Deposited by Radio-Frequency Glow Discharge
Authors: Takeshita Tetsuyoshi , Inokuma Takao , Yoshihiro Kurata Yoshihiro Kurata , Seiichi Hasegawa Seiichi Hasegawa
Published: February 2005

Polycrystalline SiC films were deposited by rf glow-discharge decomposition of silane-methane mixtures under heavy hydrogen dilution. As a result of X-ray diffraction measurement, the lattice parameter is found to be closely related to the crystallinity. Variation in the lattice parameter reflects the presence of strain in the films. It is shown that the crystallinity improves with increasing deposition temperature, although the improvement is saturated above 700°C. This saturation is interpreted in terms of the strain due to C-C bonds.
Optical Image Processing Using Liquid Crystal Panels
Authors: Yasuyuki Hanazawa Yasuyuki Hanazawa , Tatsuo Uchida Tatsuo Uchida
Published: February 2005

The authors have already proposed an optical parallel logic device using two liquid crystal panels and three color polarizers with suitable absorption property. This device can execute all sixteen types of binary logic by changing the wavelength and direction of polarization of incident light. In this paper, the authors propose an optical parallel logic device in which the number of wavelengths required for the operation is decreased from four to three, thereby eliminating the need for a steep absorption edge for the color polarizers, which enables the use of commercially available color polarizers.
Time-of-Flight Measurement of Particles with Laser-Induced Fluorescence in the Plume Produced by Laser Ablation of YBa2Cu3O7-x Target
Authors: Okada Tatsuo , Shibamaru Noboru , Yasushi Nakayama Yasushi Nakayama , Mitsuo Maeda Mitsuo Maeda
Published: February 2005

The time-of-flight (TOF) distributions of nonemissive particles in the plume produced by the laser ablation of an YBa2Cu3O7-x
target are measured by laser-induced fluorescence spectroscopy (LIF). The TOF distributions of Ba atoms and BaO molecules are presented for different O2 pressures, and the reaction kinetics with O2 are discussed.
1/f Fluctuations of Phonon Energy in Water
Authors: Toshimitsu Musha Toshimitsu Musha , Gábor Borbély Gábor Borbély
Published: February 2005

Brillouin scattering of laser light at the wavelength of 514.5 nm has shown that fractional phonon number fluctuations in water at about 5 GHz have a 1/f spectrum from 10-3 Hz up to the frequency where the spectrum merges into photon shot noise. The power spectrum is inversely proportional to the number of phonon modes N which are involved in the scattering down to the smallest observed value N=7000. The spectrum per phonon mode is equal to 3/f provided the observed 1/N dependence continues down to N=1. Energy partition in phonon modes does not reach equilibrium, at least over the time scale of hours.