bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of Large Single Crystals of Black Phosphorus under High Pressure
Authors: Endo Shoichi , Akahama Yuichi , Terada Shin-ichi , Narita Shin-ichiro
Published: November 2005

A large volume high pressure apparatus has made it possible to grow large single crystals of black phosphorus, P. After converting red P powder into black P under a high pressure of 10 kbar at high temperature, a melt of polycrystalline black P has been gradually solidified to bring about the growth of single crystals. Crystal sizes larger than 5×5×10 mm3 are, for the first time, adequate for various measurements of the physical properties expected for this narrow gap semiconductor with a special layered structure. An X-ray analysis has proved the good single crystalline structure.
Very Short Wavelength (621.4 nm) Room Temperature Pulsed Operation of InGaAsP Lasers
Authors: Fujimoto Akira , Yasuda Hirohiko , Shimura Mikihiko , Yamashita Shigeaki
Published: November 2005

InGaAsP/InGaAsP double-heterostructure laser diodes with wavelength as short as 621.4 nm at room temperature were demonstrated and their growth conditions were described. The laser diodes were constructed by InGaAsP grown on GaAs0.61P0.39 substrates by liquid phase epitaxy. Their threshold current densities were approximately 1.19×105 A/cm2 in pulsed room temperature operation.
Effects of Arsenic Pressure on GaAs Heat-Treated in Hydrogen
Authors: Ohsawa Jun , Ikeda Kenji , Takahashi Kazuhisa , Susaki Wataru
Published: November 2005

The arsenic partial pressure required to suppress the thermal decomposition of GaAs surfaces was determined experimentally by introducing AsH3 into the reactor tube. The required partial pressure agreed well with the equilibrium pressure of As2 over the Ga–As liquidus. Although thermal conversion of the surface region was not prevented by the same pressure, a remarkable decay was observed in the intensity of the associated photoluminescence peak at 1.41 eV.
Resistive Ion-Acceleration in a Plasma Focus
Authors: Tanimoto Mitsumori , Koyama Kazuyoshi
Published: November 2005

It is shown that there appears a strong resistive electric field in plasma focus discharges due to the effect of the self-magnetic-field insulation. This field, much more prevalent than an inductive one, can accelerate ions up to a directed energy of the order of MeV. A simple scaling is given for peak ion-energy and compared with recent experimental results.
Photo-Annealing of Fatigue in Photoluminescence of Hydrogenated Amorphous Silicon
Authors: Tomozane Mamoru , Hasegawa Fumio , Kawabe Mitsuo , Nannichi Yasuo
Published: November 2005

It was found that fatigue in photoluminescence of hydrogenated amorphous silicon could be photo-annealed with infrared light. This photo-annealing effect supports the three state model of the fatigue which consists of initial, intermediate and final fatigued state. Different fatigue behavior at two different temperatures (77 K and 294 K) is also interpreted by the model.
Formation of Semiconductive Metal-Sulfide at Interface of (SN)x-Metal Junction
Authors: Yoshino Katsumi , Ura Shogo , Sasa Shigehiko , Kaneto Keiichi , Inuishi Yoshio
Published: November 2005

Semiconductive metal-sulfides such as Cu2S, Ag2S, etc. are found to be formed at the interface between (SN)
x
and various metals. The electrical properties of these sulfides are studied.
Photoluminescence Decay in Amorphous As2S3
Authors: Murayama Kazuro , Ninomiya Toshiyuki
Published: November 2005

The decay of the intensity of the luminescence in a-As2S3with the energies of 1.16 and 1.57 eV was measured from 10-8sec to 2×10-3sec at 4.2 K. The shape of the decay curves shows three kinds of luminescence whose intensity decays according to the empirical decay function (f(t)=tn-1exp -(t/τ)n) with effective decay times (τ) of 2×10-8, 2×10-6and 2×10-4sec. Each luminescence process is discussed in this paper.
Inhomogeneity in Semi-Insulating GaAs Revealed by Scanning Leakage Current Measurements
Authors: Matsumoto Yoshishige , Watanabe Hisao
Published: November 2005

Inhomogeneity in semi-insulating (SI)-GaAs has been examined by scanning leakage current (I
L) measurements. The observed leakage current exhibits broad intensity variation accompanying short period sharp fluctuation along both radial and pulling directions. The undoped SI-GaAs generally shows marked inhomogeneity of the leakage current compared with the Cr-doped GaAs. The broad I
L intensity variation along the radial direction is correlated with dislocation distribution. Thermal annealing at 850°C for 1 hour in H2 significantly smooths out the inhomogeneity.
Brillouin Scattering from PMMA under Uniaxial Tensile Stress
Authors: Yap Ber-Chin , Shichijyo Shiro , Matsushige Kazumi , Takemura Tetuo
Published: November 2005

Longitudinal hypersonic velocities in PMMA under uniaxial tensile stress at room temperature were studied. It was observed that the velocity of local thermal phonons along the stress direction showed a gradual softening with the applied stress, and this softening took place even at the stress level where a macroscopic tensile measurement would reveal a relatively linear stress-strain relationship. Present results suggest that the local softening leads to the craze formation in PMMA. However, the local phonons perpendicular to the stress showed no softening. These facts explain the craze formation profile appearing on the sample.
Sensitive Detection of Hydrogen in a-Si: H by Coincidence Measurement of Elastically Scattered 100 MeV 3He2+ Ions and Recoil Protons
Authors: Fukuda Noboru , Imura Takeshi , Hiraki Akio , Itahashi Takahisa , Fukuda Tomokazu , Tanaka Masayoshi
Published: November 2005

We have drastically improved the sensitivity of the nuclear elastic scattering (NES) method for determining hydrogen concentrations in hydrogenated amorphous silicon (a-Si: H) films. A beam of 100 MeV 3He2+ ions was used in the experiment. By taking the coincidence of detection of the scattered 3He ion with that of the recoil proton, we could achieve a sensitivity of 0.1 atomic percent with a precision of about 1 percent for 1 µm films.
Efficient PPF-αNPO Energy Transfer Dye Laser in Ultraviolet Region
Authors: Muto Shinzo , Ito Chiaki , Inaba Humio
Published: November 2005

Efficient energy transfer dye laser (ETDL) in the near ultraviolet region was performed in PPF-αNPO dye mixtures pumped by a N2 laser. As the PPF concentration increases, the sensitized αNPO laser power increases remarkably and its lasing wavelength largely shifts towards a shorter wavelength compared to an unsensitized system. An improved tunable range realized by this mixture system is also demonstrated.
Annealing Behavior of Damage Introduced in GaAs by Reactive Ion Beam Etching
Authors: Yamane Yasuro , Yamasaki Kimiyoshi , Mizutani Takashi
Published: November 2005

Characteristics for damage introduced in GaAs by Reactive Ion Beam Etching (RIBE) are reported. RIBE introduced damage has mostly been recovered by low temperature annealing around 300°C. This recovery includes diffusion of and reduction in carrier killer.
Gap-State Profiles of a-Si: H Deduced from Below-Gap Optical Absorption
Authors: Yamasaki Satoshi , Oheda Hidetoshi , Matsuda Akihisa , Okushi Hideyo , Tanaka Kazunobu
Published: November 2005

We determined the gap-state profiles N(E) of undoped and P-doped a-Si: H from their below-gap optical absorption spectra through theoretical simulation under the assumption of constant matrix elements (i.e., Davis-Mott approximation). It is demonstrated that the conduction band tail has a sharper edge than the valence band, and the incorporation of P atom creates a broad band in N(E) around 0.6 eV above the mobility edge of the valence band. The origin of the broad band is speculated to be 3-fold coordinated P-atom or its relevant defect. A validity of the Davis-Mott approximation is confirmed experimentally.
Leakage Current IL Variation Correlated with Dislocation Density in Undoped, Semi-Insulating LEC-GaAs
Authors: Miyazawa Shintaro , Mizutani Takashi , Yamazaki Hajime
Published: November 2005

Leakage current I
L equivalent to sheet resistance was measured by the two-point probe method, and was directly correlated with dislocation density variation across (100) wafers of undoped, semi-insulating LEC-grown GaAs. It was found, for the first time, that leakage current I
L variation corresponds closely to dislocation density.
Czochralski Silicon Crystal Growth in the Vertical Magnetic Field
Authors: Hoshikawa Keigo
Published: November 2005

Czochralski (CZ) silicon crystals with striation free and microscopic homogeneous dopant concentrations are grown under the presence of an axially symmetric vertical magnetic field. The thermal convections of 3.5 kg of molten silicon in a crucible are successfully suppressed by a magnetic field of more than 1000 Oe in strength. Many advantages are found for the method developed in comparison with the conventional transverse magnetic field method in use.
InP MESFET Grown by MOCVD
Authors: Ogura Mototsugu , Inoue Kaoru , Ban Yuzaburoh , Uno Tomoaki , Morisaki Motoji , Hase Nobuyasu
Published: November 2005

MESFET devices with 2 µm gate length have been fabricated on InP epitaxial layers grown by the MOCVD technique on Fe-doped semi-insulating InP substrates. The best electrical properties of InP epitaxial films have been measured and are n=2.7×1015 cm-3 and µ=3500 cm2/V·s at room temperature. The barrier height and the ideality factor of Au-n InP Schottky diode were estimated to be 0.66 eV and 1.18, respectively. Depletion mode n-channel MESFET has shown transconductance of ∼90 mS/mm and the saturation drain current of ∼20 mA at zero gate bias.
Properties of ZnS Thin-Films Grown by Ionized-Cluster Beam Deposition
Authors: Ohkawa Yasushi , Oki Ken'ichi , Wakitani Masayuki , Miura Shoshin , Umeda Shozo
Published: November 2005

The properties of ZnS thin-films grown by the ionized-cluster beam (ICB) deposition at a low substrate temperature have been investigated. The crystallinity of the deposited films is dependent on an accelerating voltage of ionized-clusters. It is found that a highly crystalline ZnS film can be grown at a relatively low substrate temperature of 130°C by optimizing the accelerating voltage.
Single Crystal Growth of Superconducting BaPb1-xBixO3 from PbO2–Bi2O3–BaPbO3 Solution
Authors: Katsui Akinori
Published: November 2005

Single crystals of superconducting BaPb1-x
Bi
x
O3 of mm-size are obtained by slowly cooling PbO2–Bi2O3–BaPbO3 solution. It is shown from Meissner effect results that the as-grown crystals are superconducting and the critical temperature is in the temperature range from 6.3 to 10.8 K, dependent on starting composition and growth condition.
Bias Light Wavelength Dependence of Minority Carrier Diffusion Length of EFG Silicon Ribbon Solar Cells
Authors: Shimokawa Ryuichi , Hayashi Yutaka
Published: November 2005

Local spectral photoresponse of EFG ribbon solar cells was measured as a function of bias light wavelength and intensity. The bias light wavelength was found to have small influence on the spectral response in local positions with longer (≃89 µm) and shorter (≃7 µm) diffusion length, but large influence on that in positions with medium diffusion length (≃20 µm). The effective minority carrier diffusion length estimated from the spectral response measurement was found to increase semilogarithmically with the intensity at various bias light wavelengths. The effect of bias light wavelength on diffusion length is explained by the penetration depth of bias light into solar cells.
Frequency Stabilization of AlGaAs Semiconductor Laser Based on the 85Rb-D2 Line
Authors: Tsuchida Hidemi , Ohtsu Motoichi , Tako Toshiharu , Kuramochi Naimu , Oura Nobunori
Published: November 2005

The frequency of an AlGaAs semiconductor laser was stabilized by using the linear absorption spectrum of the 85Rb-D2 line. By controlling the injection current, the frequency stability of 3.0×10-10≧σ≧1.4×10-12 was obtained for 10 ms≦τ≦500 s. First observation of the saturated absorption spectrum of the 85Rb-D2 line is demonstrated, which can be used as a frequency reference to improve the frequency stability.
Selective Silicon Epitaxy Using Reduced Pressure Technique
Authors: Tanno Kohetsu , Endo Nobuhiro , Kitajima Hiroshi , Kurogi Yukinori , Tsuya Hideki
Published: November 2005

Silicon selective epitaxial growth using the SiH2Cl2–HCl–H2 system was successfully accomplished on a window surrounded by fine patterned insulator films as a mask. Surface planarity was obtained at less than 80 Torr reduced pressure. Good selectivity was realized by suitable HCl injection during epitaxial growth. Moreover, it was found that the induced defect density on the epi-layer was less at lower growth temperature.
Antiferroelectricity and Ferroelectricity in Rb2ZnBr4
Authors: Yamaguchi Toshihisa , Sawada Shozo , Takashige Masaaki , Nakamura Terutaro
Published: November 2005

Rb2ZnBr4 has been found to show antiferroelectricity along the b-axis in the phase from 73 K to 108 K and ferroelectricity along the a-axis throughout the four phases below 192 K.
MOVPE Growth of Ga1-xAlxAs–GaAs Quantum Well Heterostructures
Authors: Frijlink P. M. , Maluenda J.
Published: November 2005

Ga1-x
Al
x
As–GaAs quantum wells are grown by MOVPE. Wells as narrow as 25 Å are made. Interface quality in relation to alloy clustering and abruptness in change of Al-content are characterized with the aid of luminescence spectrum measurements. A remarkable agreement is found between the experimental n=1 electron to heavy hole transition energies and those which are calculated with the simple rectangular well model. The results indicate that the Al-content changes at the interfaces over less than one unit cell.
Microcrystalline Si: H Film and Its Application to Solar Cells
Authors: Uchida Yoshiyuki , Ichimura Takeshige , Ueno Masakazu , Haruki Hiromu
Published: November 2005

The photovoltaic performance of a new type amorphous silicon solar cell with ITO/n-i-p/ss solar cell in which phosphorus-doped microcrystalline (µc) Si: H is applied as the window-side layer is described in conjunction with the optical properties of the µc-Si: H film. By applying this film, the short-circuit current in the cell is improved over 10% in comparison with that of a conventional ITO/n-i-p/ss cell. This improvement is explained by the high transparency of the µc-Si: H and by a new concept of “double AR effect” of the crystallized window-side layer which reduces the surface reflectance.
Ray Tracing in a Distributed-Index Planar Micro-Lens
Authors: Misawa Shigeyoshi , Oikawa Masahiro , Iga Kenichi
Published: November 2005

Light rays in a distributed-index planar micro-lens have been traced with the help of a ray equation and the measured value of index distribution, and the light intensity distribution on the focal plane has been obtained. A 3-D representation of the refractive index distribution has been proposed. It has been expressed by power series expansion with respect to the transverse and axial distance, where axial symmetry has been assumed. The obtained ray trajectory and the intensity distribution on the focal plane can be used for the estimation of spot size and spherical aberration. Fairly good agreement has been obtained between the measured intensity distribution and that obtained from ray tracing.
New Type of A5B3 Structure in Al–Ti and Ga–Ti Systems; Al5Ti3 and Ga5Ti3
Authors: Miida Rokuro , Hashimoto Satoshi , Watanabe Denjiro
Published: November 2005

By electron diffraction and X-ray powder diffraction, a new type of A5B3-structure based on the L10-type was found in the Al–Ti and Ga–Ti systems; Al5Ti3 and Ga5Ti3. The structure has a tetragonal symmetry with the space group, P4/m
b
m, and the lattice constants, 2√2a
f and c
f, where a
f and c
f are those of the fundamental L10-type cell. 20 Al (or Ga) and 12 Ti atoms are contained in the unit cell. The structure can be described as follows: it consists of the domains based on the L12, containing 3×2 columns of Ti atoms, and the domain boundaries have the L10-type atomic arrangement.
Ordered Structures of Au–Mn Alloys Containing 25–28 at.%Mn Studied by High Voltage, High Resolution Electron Microseopy
Authors: Terasaki Osamu , Watanabe Denjiro
Published: November 2005

Changes in the ordered structures of the Au–Mn system with composition have been studied in the range of 25–28 at.%Mn with the aid of high resolution images taken with a 1 MV electron microscope. The orthorhombic structure (2d-Au3Mn) existing at 24 at.%Mn is not stable when Mn content increases: symmetry of the structure changes gradually to monoclinic, and the excess Mn atoms are accemmodated by forming the Mn–Mn nearest-neighbour pairs aligned in the <120> directions. The number of Mn–Mn pairs along the <120> increases with increase in Mn content, and the structure transforms continuously to the Au5Mn2.
Simplified High Voltage Hollow Cathode Discharge Tube for Excitation Source of Metal Vapor Lasers
Authors: Iijima Tetsuo
Published: November 2005

A simplified high voltage hollow cathode discharge tube with internal helical anode system is newly proposed as an excitation source of metal vapor lasers. The radial distribution of luminous intensity emitted from this discharge tube is symmetric with respect to the axis. The current-voltage characteristics of this type of discharge can be continuously controlled by changing the distance between the threads of the helical anode.
Microwave Undulator
Authors: Shintake Tsumoru , Huke Kazuo , Tanaka Jiro , Sato Isamu , Kumabe Isao
Published: November 2005

An undulator which uses a microwave field instead of a static, periodic magnetic field has been operated successfully at the Photon Factory electron linac. When S-band microwave power of 300 kW is fed into the undulator cavity which has a period of 5.5 cm, an equivalent magnetic field of 0.45 kG and K-parameter of 0.24. At a beam energy of 100–500 MeV, quasimonochromatic synchrotron radiation in the visible region was observed and the spectrum was measured.
Time Dependent Observation of the Conoscopic Figures of Twisted Liquid Crystal
Authors: Miyoshi Katsuya , Hashimoto Yoshiro , Muratomi Keiji , Yamashita Masafumi , Yukinari Toshiro , Ishiguro Kozo
Published: November 2005

The conoscopic figures of a twisted p type nematic liquid crystal of about 10 µm thickness are recorded as the function of pulse number of the applied alternating electric field of rectangular wave form. The newly obtained results are as follows;
(1) the position of the center of the isogyers, or the direction of optic axis, depends only on the amplitude of the alternating electric field and does not depend on the applied pulse number,
(2) the visibility of the isogyers increases with the increase in pulse number without changing position. A possible mechanism of the alignment of liquid crystal molecule is suggested.
Ba(Mg1/3Ta2/3)O3 Ceramics with Temperature-Stable High Dielectric Constant and Low Microwave Loss
Authors: Nomura Shoichiro , Toyama Keiichiro , Kaneta Kumiko
Published: November 2005

A dense ceramic with an ordered perovskite structure with chemical formula Ba(Mg1/3Ta2/3)O3 is prepared, aiming at materials for a dielectric resonator with temperature-stable high dielectric contsant and low loss at microwave frequency. A small amount of Mn ion is doped to the sample to complete the sintering. The dielectric constant and unloaded Q are 25 and 16800 at 10.5 GHz respectively. The temperature coefficient of resonant frequency is estimated as 2.7 ppm/°C in the vicinity of room temperature. The value of Q we obtained is the highest among those reported so far on ceramics having a similar characteristic.
Determination of Helical Pitch in Homeotropic Cell of Chiral Smectic C Liquid Crystal Using F-Center Laser
Authors: Takezoe Hideo , Kondo Katsumi , Fukuda Atsuo , Kuze Eiichi
Published: November 2005

The selective reflection is observed in a monodomain homeotropic cell of chiral smectic C liquid crystal (DOBA MBC). In conjunction with the refractive index, the structural helical pitch is determined as a function of temperature. The results agree well with our previous results obtained by diffraction technique as well as optical microscope observation in a monodomain homogeneous cell. This agreement experimentally confirms that the fringe spacing observed under an optical microscope is ascribed to the full pitch. The large difference in the helical pitches determined by some investigators is also discussed.
Axial Mode Spectra of Planar Stripe Geometry Laser Diodes
Authors: Pietzsch Joachim , Kamiya Takeshi
Published: November 2005

The influence of spontaneous emission on the axial mode spectrum of semiconductor laser diodes is described by solving the wave equation of each mode and calculating the rate of spontaneous emission coupled into the mode. Since we employ a quantum mechanical gain model, spectral gain and spontaneous emission are unambiguously correlated to carrier density. Spectra of axial modes are calculated for different power levels, gain widths and cavity lengths.
Graphoepitaxy of Ge Films on SiO2 by Zone Melting Recrystallization
Authors: Sakano Kiyoji , Moriwaki Kazuyuki , Aritome Hiroaki , Namba Susumu
Published: November 2005

Graphoepitaxy of vacuum-evaporated Ge films on amorphous fused quartz or thermally grown SiO2 substrates with surface-relief gratings engraved by reactive ion etching has been performed by a heating process of zone melting. We observed that zone melted films on gratings consisted of grains of 2–10 µm size with <100> direction parallel to the grating axis and perpendicular to the substrate plane.
GaInAsP/InP DH Laser with a Current Blocking Layer Made by Be Implantation
Authors: Uchiyama Seiji , Moriki Kazunori , Iga Kenichi , Furukawa Seijiro
Published: November 2005

A GaInAsP/InP laser (λ=1.3 µm) with a current blocking layer made by Be implantation has been fabricated. Be-ions were implanted with 70 keV into an n-InP substrate at room temperature and 2.2×1014 cm-2 of dose. Thermal annealing was applied in a furnace during the LPE (Liquid Phase Epitaxial) growth. The breaking of the forward bias associated with the blocking region was 2 V. The minimum threshold current was 160 mA for 2.5 µm width of waveguide and 250 µm cavity length.
Multimode-Oscillating Behavior in Index-Guiding V-Channeled Substrate Inner Stripe Lasers Depending on Structural Factor
Authors: Hayakawa Toshiro , Yano Seiki , Hijikata Toshiki
Published: November 2005

Longitudinal-mode behavior in v-channeled substrate inner stripe (VSIS) lasers is presented. The lasing starts on multimodes and stabilizes on a single longitudinal mode with increasing current of more than a few percent above the threshold. Thus, the intrinsic spectral noise intensity shows two peaks at and slightly above the threshold. These characteristics are considered to result from the unique structure of VSIS lasers with small built-in refractive-index difference and narrow current channel.
Dynamics of Intense Pulsed Proton Beam in the Nagaoka ETIGO-I
Authors: Tanaka Hajime , Konno Kohji , Masugata Katsumi , Yatsui Kiyoshi , Matsui Masao
Published: November 2005

Dynamics of an intense pulsed proton beam have been studied by measuring nuclear reactions as well as by a biased ion-collector (BIC). When the ion-current density (Ji) is small such thatJi<30 A/cm2, the proton number measured by BIC is in good agreement with that by nuclear activation. Good linearity exists between time integrated γ-ray signal and proton number measured by the activation. Hence, it would be possible to obtain the proton number quantitatively even when a target "blow-off" takes place atJi>1 kA/cm2. Prompt γ-ray is also measured by the time-of-flight method to yield reasonable agreement with the applied peak potential.
Comparison of Single and Multiple Period Modulation Doped AlxGa1-xAs/GaAs Heterostructures for FETs
Authors: Drummond T. J. , Keever M. , Morkoç H.
Published: November 2005

Current-voltage characteristics of single and three period modulation doped heterostructures intended for high speed FETs are compared. Single period structures exhibited linear characteristics up to 2 kV/cm at 300 K and non-linear characteristics were observed at lower temperatures. Three period structures grown under similar conditions showed negative differential resistance at field strengths above 1 kV/cm, which is attributed to structural properties of interfaces between the ternary and the overlaying binary layers. Although it is possible to improve these interfaces associated with multiple period structures somewhat, the single period structures were found more suitable for high speed FET applications.
LPE Growth of In1-xGaxAs1-yPy with Narrow Photoluminescence Spectrum on GaAs (111)B Substrates
Authors: Kato Takamasa , Matsumoto Takashi , Ishida Tetsuro
Published: November 2005

The growth conditions of In1-x
Ga
x
As1-y
P
y
, layers on GaAs (111)B substrate and the photoluminescence (PL) properties of these layers are described. The temperature difference liquid phase epitaxial (LPE) method was used for crystal growth. Single PL peak corresponding to band-to-band transition was observed from the layers over the range of 1.73\lesssimE
g\lesssim1.98 eV at 77 K. The half width of the PL band was less than 20 meV and independent of the peak energy. These results show that the grown layers have good crystalline qualities.
Interaction Potential between He+ and Ti in a keV Range as Revealed by a Specialized Technique in Ion Scattering Spectroscopy
Authors: Aono Masakazu , Hou Yinchun , Souda Ryutaro , Oshima Chuhei , Otani Shigeki , Ishizawa Yoshio , Matsuda Kyoji , Shimizu Ryuichi
Published: November 2005

The interaction potential between He+ and Ti in a keV range has been studied by a specialized technique in low-energy ion scattering spectroscopy. The interaction potential is described well by the Thomas-Fermi-Molière potential for the interaction between neutral He and Ti with a scaled screening radius.
The Stability of Plasma-Polymerized Carbon Disulfide Films Containing Tellurium for Laser Recording
Authors: Yamazaki Hiroki , Asano Yoshihiro
Published: November 2005

The environmental stability of a laser recording medium, which consists of plasma-polymerized carbon disulfide film containing tellurium, was studied by an accelerated aging test at high temperatures. The optical change in reflectance due to oxidization of tellurium was measured. These results show that the life time of the medium at ambient environment is more than 10 years.
Rapid Pulse Magnetization of Laminated Iron Cores
Authors: Hirano Kei-ichi , Furuya Katsuhiko , Tanjyo Masayasu , Yoshimoto Hiroshi
Published: November 2005

A simple magnetization model for laminated iron cores is proposed. It assumes that a surface layer δ0 is magnetized before the saturated fornt propagates into the lamination. Fairly good agreements between the model and the experiment are achieved. Using this model, relations between the voltage and the current through a saturable reactor are derived.
Asymmetric Frequency Response of Semiconductor Laser Amplifiers
Authors: Nakai Tetsuya , Ito Ryoichi , Ogasawara Nagaatsu
Published: November 2005

Asymmetry in the frequency response of semiconductor laser amplifiers operating just below lasing threshold is investigated experimentally and theoretically. Frequency response of the amplifier is measured using a transient shift of the oscillation wavelength when the laser is operated in pulsed mode. The observed asymmetry is explained in terms of the refractive index change due to decrease in the active-region carrier density accompanied by optical amplification.
Crystal and Liquid-Crystal Structure of a Disk-like Molecule Triphenylene Hexa-n-Dodecanoate
Authors: Takabatake Minoru , Iwayanagi Shigeo
Published: November 2005

A disk-like molecule triphenylene 2,3,6,7,10,11-hexa-n-dodecanoate is known for its three columnar mesophases D0, D1, D2 in the order of ascending temperature. X-ray diagrams obtained from oriented specimens show that the plane of triphenylene core of the molecule is not perpendicular to the columnar axis in both D0 and D1 mesophases as well as in the crystalline phase; the hydrocarbon side chains are in a relatively regular array throughout these phases except in the D2 phase. The two-dimensional lattice parameters determined for the array of the columns are different from those reported previously.
On the Sensitivity of the Fluorescence EXAFS
Authors: Namikawa Kazumichi , Hosoya Sukeaki
Published: November 2005

The sensitivity of the fluorescence EXAFS is discussed on the basis of a phenomenological theory and shown to be estimated by a parameter defined by absorption coefficients. Measurements of the fluorescence EXAFS and of the transmission EXAFS are performed on Fe, Cr, and Ni contained in stainless steel SUS 304 with different ratios. Both theoretical and experimental results exhibit a high sensitivity of the fluorescence EXAFS for a dilute component less than about 10%.
Diamond-Anvil Cell Equipped with a Worm Gear Intensifier for Pressure Generation at Low Temperature
Authors: Endo Shoichi , Mishima Osamu , Ohno Yoshikazu , Kawamura Tetsuya
Published: November 2005

A diamond-anvil cell for which pressure can be controlled at low temperature has been developed. A torque applied to the outside of the cryostat is intensified by a double worm gear so as to force diamond anvils together for pressure generation. Pressure up to 180 kbar has been confirmed at 1.8 K on the basis of ruby fluorescent measurements. The device, with a horizontal beam axis, is favorable for optical, X-ray and other similar experiments using an ordinary cryostat.
Comparison between Atmospheric and Reduced Pressure GaAs MOCVD
Authors: Kobayashi Naoki , Fukui Takashi , Horikoshi Yoshiji
Published: November 2005

MOCVD was employed to grow GaAs eritaxial layers at both atmospheric and reduced pressure (76 Torr), while the flow rate and TMG concentration remained the same. Under both growth conditions, an epitaxial layer with a liquid nitrogen electron mobility of 95,000 cm2/V·sec at an electron concentration of 5×1014cm-3 was reproducibly obtained. The growth rate with reduced pressure was larger than with atmospheric pressure. Dependence of the electrical properties upon [AsH3]/[TMG] in the n type region was almost identical for both growth conditions. On the other hand, with reduced pressure growth, the p type region shifted to a higher [AsH3]/[TMG] location, and there was a higher hole concentration than with atmospheric pressure growth. In addition to reporting these observations, this paper will discuss the impurity incorporation mechanism in the p type region.
Ferroelectric Polarization Switching in Polyvinylidene Fluoride
Authors: Takase Yoshihiko , Odajima Akira
Published: November 2005

Switching transients of current and charge in form I PVDF have been measured in the time region faster than 1 ms under high electric field (140–200 MV/m) and in the temperature range from -20 to 20°C. A careful consideration in composing a switching circuit has been paid to reduce its time constant. The activation energy and field for the switching transient have been determined to be 0.63 eV (E=200 MV/m, T=-20–20°C) and 1.3 GV/m (T=20°C, E=140–200 MV/m), respectively.
Piezoelectricity of Poly (vinylidene Fluoride) under High Pressure
Authors: Tanaka Hiroshi , Takayama Koichi , Taki Seiji , Takemura Tetuo
Published: November 2005

Pressure dependence of piezoelectric stress constant e
31, dielectric constant ε
3, electrostriction constant κ31, and Poisson's ratio m
31 of poly (vinylidene fluoride) film were measured. A new method for measurement of m
31 under high pressure was designed. The observed e
31 which decreased with increasing pressure was well explained by the composite model theory proposed by Wada and Hayakawa. Pressure dependences of the fractional contributions of κ31 and m
31 to e
31 were clarified and the decrease of e
31 was revealed to come from the decrease of m
31 due to the increase in bulk modulus of amorphous phase.
Ion Oxidation of Si(111)
Authors: Daimon Hiroshi , Murata Yoshitada
Published: November 2005

The origin of the promotion of oxidation when an ion gauge is turned on during oxygen exposure on cleaved Si(111) was studied by photoemission (h
v=55, 130eV). The reactivity in the oxide formation of ions, neutral excited species, and ground state oxygen molecules has been measured. The origin of the promotion of oxidation was attributed to ions, and the efficiency in the oxide formation of ions has been found to the greater than that expected from the amount of incident ions.
Role of Dislocations in Semi-Insulation Mechanism in Undoped LEC GaAs Crystal
Authors: Kamejima Taibun , Shimura Fumio , Matsumoto Yoshishige , Watanabe Hisao , Matsui Junji
Published: November 2005

For the undoped semi-insulating LEC GaAs crystal, microscopic inhomogeneity was investigated on the fixed position by using cathodoluminescence (CL), secondary ion mass spectrometry (SIMS), X-ray topography (XRT) and scanning leakage current measurement (I

L
). Microscale fluctuations observed in these measurements were attributed to the cellular dislocation structures. It was suggested that the impurity gettering effect of dislocation plays an important role in the semi-insulation mechanism in GaAs crystal. Carriers are inactive in the boundary region of cell structures but are active in the inner region of cell structures.
Fabrication of High Quality NbN/Pb Josephson Tunnel Junctions with Plasma Oxidized Barriers
Authors: Hikita Makoto , Takei Koji , Iwata Tsunekazu , Igarashi Masaru
Published: November 2005

Extremely low subgap leakage current NbN/Pb tunnel junctions, in which V

m

s exceed 100 mV, were fabricated using a low energy rf plasma oxidation technique. This was done under conditions where cathode self bias voltages V
CSB were below 200 V. XPS study shows that NbN surface oxide layer thickness increases from 1.5 nm to 4.5 nm after Ar ions bombarded the NbN surface at V
CSB
s above 200V. Ar ion bombardment at V
CSB
s above 200V produces a damaged layer on the NbN surface. Artifical initial oxide layer formation subsequent to NbN film preparation is effective in reducing subgap current under lower V
CSB conditions for cleaning and oxidation.
Determination of Energies of Intense Light Ion Beams by the Boron-Nitride Nuclear Activation Method
Authors: Ozaki Tetsu , Miyamoto Shuji , Imasaki Kazuo , Chihara Ichiro , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

A technique capable of determining proton energies below 1 MeV by the Boron-Nitride (BN) nuclear activation method is described. This method is convenient and can be used even in a gas plasma. This situation often occures in a light ion beam transport experiment for particle beam fusion research. Activation results were compared with ion energies obtained from biased charge collectors.
CW-Laser Induced Dynamic Grating and Subpicosecond Hole Relaxation Time in p-Ge
Authors: Kawai Masatoshi , Sato Heihachi , Miyakawa Toru , Tako Toshiharu
Published: November 2005

Bragg diffraction intensity of 3.39 µm He–Ne laser beam by a dynamic grating induced in p-Ge by two beams of CW-CO2 lasers is measured as a function of detuning frequency Δω and of the intensities of two lasers.
From the Δω dependence of the intensity of diffracted beam the relaxation time T
h=0.2 ps of the heavy hole distribution function is estimated in reasonable agreement with theoretical prediction.
Image Transmission by a Step-Index Multimode Fiber
Authors: Batubara John E. , Iga Kenichi , Oikawa Masahiro
Published: November 2005

We have demonstrated the transmission of two-dimensional images by the use of a single piece of step-index multimode fiber. We have used a pair of slits in front of and behind the fiber and those slits were rotated simultaneously to eliminate skew rays. In each direction of the slits, light from the associated position of the point source was transmitted through the fiber and the image was reconstructed on film. The result shows the applicability of this method of eliminating skew rays to transmit a two-dimensional image through a piece of step-index multimode fiber. Some degradations on the image quality might be eliminated by improving the set up or using computer processing.
Effects of Sulfate Ion on Gas Sensitive Properties of α-Fe2O3 Ceramics
Authors: Nakatani Yoshihiko , Matsuoka Michio
Published: November 2005

Alpha hematite (α-Fe2O3) has been considered to have only a poor sensitivity to reducing gases. However remarkable gas sensitive properties were observed in the α-Fe2O3 prepared from iron salts containing sulfate ion (SO4
-) by hydrolysis and precipitation. The sulfate ion remains in the α-Fe2O3 but vaporizes at near 760°C. The vaporization causes crystallization of the α-Fe2O3 and consequently results in a decrease in gas sensitivity. The sulfate ion is an extremely important factor in controlling the microstructure and plays a significant role in the gas sensitive properties of the α-Fe2O3 ceramics.
Controlled High-Tilt-Angle Nematic Alignment Compatible with Glass Frit Sealing
Authors: Hiroshima Koki
Published: November 2005

A new SiO oblique evaporation procedure for high-tilt-angle nematic liquid crystal alignment with no organic surfactants and no dopants is proposed. It covers a wide tilt range of 0° to 60° with respect to the substrate normal. In the procedure the azimuth of SiO beam changes continuously during evaporation, although the incident angle does not change. By choosing the azimuthal distribution of deposition, the tilt bias of the director can be controlled. The aligning layers are heatproof and should be of use in producing improved positive-type guest-host display devices.
Preparation of High Quality n-Hg0.8Cd0.2Te Epitaxial Layer and Its Application to Infrared Detector (λ=8–14 µm)
Authors: Nagahama Kouki , Ohkata Ryouji , Murotani Toshio
Published: November 2005

High mobility n-type Hg0.8Cd0.2Te liquid phase epitaxial layers on CdTe substrates are reproducibly obtained by annealing the layers under Hg overpressure and then by diffusing indium into the annealed layers. Their carrier concentrations and Hall mobilities are in the range of (1.5–2.0)×1015cm-3and (1.0–1.5)×105cm2/V·s, respectively at 77 K. A photoconductivity-type IR detector using one of these layers has detectivity Dλ*higher than 2×1010cm·Hz1/2/W in the wavelength region of 8–14 µm with a peak detectivity Dλp*of 3×1010cm·Hz1/2/W at 13 µm.
Thermal Load Test of a TiC Coated Mo Limiter during Steady State and Major Current Disruption Phases in the JFT-2 Tokamak with Neutral Beam Injection
Authors: Maeno Masaki , Sengoku Seio , Nakamura Hiroo , Yamamoto Shin , Seki Masahiro , Kawamura Hiroshi
Published: November 2005

A TiC coated Mo material has been tested as a limiter in the JFT-2 tokamak. The surface temperature of the limiter is measured with an infrared scanning camera. The maximum surface temperature rise during a steady state discharge with a neutral beam power of 700 kW is around 230°C in 25 msec and the heat flux density to the limiter is 1–4 kW/cm2. The maximum temperature rise during a current disruption with the beam power of 1 MW is about 100°C in 100–600 µsec and the density is the order of 50 kW/cm2. The TiC coated Mo material can be proof against such a high load.
Encapsulated Thermal Oxidation for Ge-APDs Passivation
Authors: Torikai Toshitaka , Hino Isao , Iwasaki Hideo , Nishida Katsuhiko
Published: November 2005

Encapsulated thermal oxidation, which includes SiO2 deposition and subsequent annealing in O2 ambient gas, has been investigated for Ge-APDs passivation. Ge-oxide growth at the SiO2/Ge interface reduced the surface state density in proportion to the oxidation temperature. This passivation method was found to be effective for the Ge-APDs dark current reduction.
Influence of Polymorphism on Growth of Stearic Acid Single Crystal in Solution
Authors: Maeyashiki Yoshiki , Okada Masakazu , Sato Kiyotaka
Published: November 2005

Stearic acid has three main crystallographic modifications, namely, the A-form (triclinic), and the B- and C-form (monoclinic). The gorwth rate against supersaturation is studied on the (110) faces of each modification and the relationship between polymorphism and the growth conditions is obtained for solution growth cases. Here the B- and C-form show parabolic growth rates against supersaturation but the A-form has an exponential growth rate curve.
Ion Beam Assisted Maskless Etching of GaAs by 50 keV Focused Ion Beam
Authors: Gamo Kenji , Ochiai Yukinori , Namba Susumu
Published: November 2005

Maskless etching of GaAs by means of an ion beam assisted etching technique has been investigated using a 50 keV focused Au beam, and it is found that ion beam assisted etching is very promising for maskless direct etching with a high etching rate. The Au+ focused beam was irradiated on GaAs in chlorine ambient gas. It was observed that this etching technique gives a smooth etched surface with an etching rate of 2 µm·min-1·mA-1·cm2, which is about 100 times larger than the value observed for physical sputter etching without chlorine gas. From the measurement of mass spectra it was observed that about 75 percent of chlorine gas reacts with residual water vapour and HCl gas is produced. It is considered that both chlorine and HCl gases play an important role in the enhancement of etching.
Characteristics of Transported Ion Beam in Laser-Initiated Plasma Channels
Authors: Ozaki Tetsu , Miyamoto Shuji , Imasaki Kazuo , Fujita Hisanori , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

The propagation of intense ion beams through a laser-initiated plasma channel is reported. The ion beams were generated using a pinch-reflex ion diode on a Reiden IV generator and were transported over 40 cm in the plasma channel. The beam orbits, estimated from the pattern on the detector-film with energy resolution, were in good agreement with theory.
Raman Spectroscopic Study on Molten Polyethylene under High Pressure
Authors: Tanaka Hiroshi , Takemura Tetuo
Published: November 2005

Raman spectral changes of the C-H stretching modes of polyethylene during melting at high pressures up to 5000 kg/cm2 were observed in detail and are explained in terms of changes in the intra- and interchain structures. It was found that the peak height ratio r=I(2890)/I(2850) in the molten state increases, and the upward shift of the 2890 cm-1 band upon melting decreases with increasing pressure. Several confirmations of the effects of intra- and interchain disordering on the ratio and the upward shift were obtained from other experimental results. It is suggested from these facts that the degree of intrachain regularity in the molten state increases with increasing pressure, and that this should contribute to the formation of extended-chain crystals under high pressure.
Analysis of the Majorana Transition and Beam Optics for the State Selection of a Hydrogen Maser
Authors: Urabe Shinji , Ohta Yasusada
Published: November 2005

The Majorana transition and the beam optics configuration are analysed for the purpose of designing the hydrogen maser state selector which selects only desired atoms for oscillation. In this state selection, the double focalization method and the Majorana transitions which reverse the atomic polarization are used in order to eliminate undesirable atoms. The polarization reversal is obtained by calculating the transition probabilities of the atomic spin in the reverse magnetic field. The beam optics configuration is also analysed for the purpose of effective elimination. Based on these analyses, the state selection is successfully attained, and about 90% of the undesirable atoms are eliminated.
Detailed Analysis of a Bitter-Type Magnet
Authors: Nakagawa Yasuaki , Miura Shigeto , Hoshi Akira , Nakajima Kikuo , Takano Hirohisa
Published: November 2005

A high-power water-cooled magnet with a Bitter-type coil has been designed, constructed and tested. The current density, the temperature rise and the electromagnetic stress have been calculated with the finite element method. The results of calculation are consistent with the experimental test. The local electromagnetic stress exceeds the yield stress of usual conductors if the coil is used for hybrid magnet which produces fields of more than 20 T with a back-up field of a superconducting coil.
Micro-State Analysis of Iron Compounds Using the 9th-Order FeKα1Line
Authors: Fujimori Haruo , Iba Hajime , Tsuchiya Hiroyuki
Published: November 2005

The X-ray spectra of 9th-order FeKα1(FeKα19), FeLα and FeLβ lines were measured for metallic iron, FeO, Fe3O4, Fe2O3, FeF2and FeF3with an excitation potential of 20 kV using an electron probe microanalyzer (EPMA). The micro-state analysis of these iron compounds using EPMA was greatly improved by observation of the FeKα19line, because its intensity relative to the FeLα line varied with the chemical state and its peak position became a marker to measure the wavelength shift of the FeLα line (ΔLα). Factors influencing the absorption effect on the measured spectra were evaluated by calculating the absorption correction factors. The wavelength shift,ΔLα did not exhibit substantial changes in electron binding energy, though it showed correlation with the valency of iron.
Ray Tracing of a Concave-Curved-Crystal Spectrometer and Its Detailed Characteristics for X-Ray Spectroscopic Diagnostics of High-Temperature Plasmas
Authors: Morita Shigeru
Published: November 2005

A method of ray tracing is presented for a spectrometer with a concave-curved crystal to be used for X-ray spectroscopic diagnostics of high-temperature plasmas. Calculations have been carried out for an LiF(200) crystal with a lowland circle of radius 50 cm and a Gaussian rocking curve. With a linear X-ray source, the most suitable parameters of the spectrometer were accurately determined by use of the ray tracing, and the characteristics were investigated in detail. The ray tracing was also applied to a point source of X-rays, and the best conditions for geometric relations between the point source and the spectrometer were found. The spectral distortion is also described here analytically. The calculated line profile including the natural broadening of the X-ray source is compared with the experimental result for FeKα1. Good agreement is obtained.
Electrification of Polymer Particles by Impact on a Metal Plate
Authors: Masui Noriaki , Murata Yuji
Published: November 2005

Impact charge and impact area of particles of nylon 66 and PMMA (3.18 mm and 2.19 mm in diameter, respectively) by a single impact on a metal plate (Cr plated brass plate) were measured under various impact speeds v (3.7 m/s ∼ 20.3 m/s) and impact angles θ(0^°∼80^°). It was found that both the impact charge and the impact area are junctions of the vertical component of the impact speed, vcos
θ, while the horizontal component, vsin
θ, was found to have no effect on them. The impact area is calculated using the theory of plastic-elastic deformation, and the measured values are found to agree well with the calculations. The impact charge density is constant within the range of the experimental conditions examined and is determined only by the combination of materials colliding with each other.
Cause of Coherent Oscillation of Domains of Nematic Liquid Crystals in DC Electric Field
Authors: Hirata Shoji , Tako Toshiharu
Published: November 2005

The domains of nematic liquid crystals begin to oscillate coherently at a certain threshold voltage in a DC electric field. The structures of the hydrodynamic motion and the molecular alignment of this oscillation are investigated and its mechanism is explained. The oscillation is attributed to the time-dependent competition between the hydrodynamic instability and the elastic stability in a non-equilibrium system. Some features of the oscillation are discussed on the basis of this mechanism.