bluuebunny/crossref_metadata_2025 huggingface dataset:
Ignition of Thermonuclear Fuels Utilising the Energy Liberated in 6LI(n,T)4He Reactions
Authors: Kanapathipillai Kanapathipillai , Murukesapilliai Murukesapilliai
Published: February 2005

6Li(n, T)4He fusion reactions occur readily at room temperature and liberate 4.8 MeV per reaction. It is shown here that this energy can be utilised to ignite thermonuclear fusion fuels. The main fuel considered here is a mixture containing equal numbers of tritium and deuterium nuclei. Rate equations and their numerical solutions are presented. The solutions show that it is possible to ignite the D-T fuel with an initial charge containing equal numbers of 6Li nuclei and neutrons. A brief sketch of a probable fusion reactor which would utilise the proposed heating scheme is also presented.
RHEED Patterns and Surface Morphology of ZnSe Homoepitaxial Films Grown by MBE
Authors: Menda Kazunori , Minato Tetsuo , Kawashima Mitsuo
Published: February 2005

Homoepitaxial films of ZnSe have been grown on (001)ZnSe substrates by molecular-beam epitaxy(MBE). These films were grown at a constant substrate temperature of 360°C. The Zn-beam pressure (P
Zn) was fixed, while the Se-beam pressure (P
Se) was varied. The surfaces during the growth were observed by reflection high-energy electron diffraction (RHEED). The grown film observed with a scanning electron microscope showed the smoothest surface for P
Se/P
Zn= 1.1, which makes the surface a c(2 × 2) surface structure. This suggests that the surface stoichiometry condition does not necessarily provide a smooth surface.
An Application of the Thermal Network Method to the Thermal Analysis of Multichip Packages (Proposal of a Simple Thermal Analysis Model)
Authors: Fukuoka Yoshitaka , Ishizuka Masaru
Published: February 2005

In recent years, electronic circuits have been required to be smaller and lighter and to have greater complexity, more multifunctions and higher reliability. High-density multichip packaging technology has been used in order to meet these requirements. The higher the density scale, the larger the power dissipation per unit area will become.
Therefore, thermal analysis becomes one of the most important design factors. However, the multichip package heat transport mode is very complex and its treatment is tedious and time consuming. This paper describes an application of the thermal network method and proposes a simple thermal analysis model for the thermal analysis of multichip packages as a preliminary thermal design tool. As a result, the validity of the thermal network method and the simple thermal analysis model can be confirmed.
Depth-Resolved Cathodoluminescence in GaAs Epilayers Grown on Si Substrates
Authors: Watanabe Yoshio , Kadota Yoshiaki , Okamoto Hiroshi , Ohmachi Yoshiro
Published: February 2005

Cathodoluminescence is used to study defects in undoped GaAs epilayers grown on Si. The GaAs epilayers include in situ thermal cycle (TC) processes and/or InGaAs-GaAs strained-layer superlattices (SLS's). In an in situ TC sample, the density of dark-spot defects is proved to increase with electron beam energy. Under the condition that the electron beam penetration depth reaches the position of the in situ TC, weak crosshatching contrasts appear, which are thought to be due to the movement and arrangement of 60°-type dislocations along the {111} planes during thermal cycle processes. In the sample with an in situ TC followed by SLS growth, distinct dark nonradiative recombination lines along <011 > directions appear in the luminescence image of the top GaAs layer. These <011 > aligned dark lines are thought to be caused by dislocations lying near the SLS/GaAs interface.
Long-Term Reliability Tests for InGaAlP Visible Laser Diodes
Authors: Ishikawa Masayuki , Okuda Hajime , Itaya Kazuhiko , Shiozawa Hideo , Uematsu Yutaka
Published: February 2005

Long-term reliability tests of over 10,000 hours have been carried out for 670-nm-wavelength InGaAlP visible laser diodes at elevated ambient temperatures beyond 50°C. Lifetime characteristics of inner stripe structure lasers were investigated from the viewpoints of structural parameter and aging conditions. At least two degradation modes were observed in the InGaAlP laser. One of them was related to facet oxidation and reduced by facet coating. The other degradation mode strongly depended on the operation current density. Mean times to failure of 24,900 hours for facet-coated thin-active-layer (0.06-µm) devices and 17,200 hours for as-cleaved-facet thick-active-layer (0.1-µm) devices were estimated at 50°C. The activation energy of the lifetime was over 1.7 eV in the temperature range between 50°C and 60°C.
A Nonlinear Optical Organic Crystal for Waveguiding SHG Devices: (-)2-(α-Methylbenzylamino)-5-Nitropyridine (MBANP)
Authors: Kondo Takashi , Morita Ryuji , Ogasawara Nagaatsu , Umegaki Shinsuke , Ito Ryoichi
Published: February 2005

A nonlinear optical organic material, (-)2-(α-methylbenzylamino)-5-nitropyridine (MBANP), has been comprehensively investigated with the objective of application to frequency doubling of laser diodes. Its molecular hyperpolarizability is as large as that of p-nitroaniline. MBANP crystallizes with a highly asymmetric molecular arrangement. The largest nonlinear optical coefficient, d
22, is measured to be 60 pm/V. The corresponding figure of merit for frequency doubling at 1.064 µm is 3.5 times larger than that for d
33 of LiNbO3. Čerenkov-radiation-type, phase-matched second-harmonic generation has been demonstrated utilizing the d
22 coefficient by making use of an appropriate waveguiding structure.
Highly Efficient, Large-Area Polycrystalline Silicon Solar Cells Fabricated Using Hydrogen Passivation Technology
Authors: Matsukuma Kunihiro , Kokunai Sigeru , Uchida Yasuaki , Suzuki Satoru , Saegusa Yukoh , Yagi Hideyuki , Saitoh Tadashi , Nishinoiri Kazuo , Shimokawa Ryuichi , Morita Keiichi
Published: February 2005

Highly efficient, large area polycrystalline silicon solar cells have been fabricated using ion implantation as a hydrogen passivation technique. A new high-current ion implanter with a bucket-type ion source has been developed to hydrogenate crystal defects in cast polycrystalline cells. Effective hydrogen passivation of the defects has been realized by implanting hydrogen ions into cast cells from the back surfaces and increasing the hydrogen ion energy and dose. A scanning light beam-induced current image of the polycrystalline cells shows that lowering of the induced current distribution at linear grain boundaries is almost completely eliminated, but not at irregular grain boundaries. The resultant polycrystalline cells exhibit a high conversion efficiency of 15.2% for a large area of 100 cm2.
Experimental Study on Soft X-Ray Radiation Emitted from a Laser-Heated Gold Cavity
Authors: Kondo Kiminori , Nishimura Hiroaki , Sakurai Hiroshi , Nishihara Katsunobu , Izawa Yasukazu , Kato Yoshiaki , Yamanaka Chiyoe , Nakai Sadao
Published: February 2005

Time evolution of soft X-ray radiation emitted from a gold cavity which is heated by intense laser light is studied. The X-ray emission from a cavity wall which is irradiated either directly or indirectly by laser light is observed. Comparison of the observed spectra with the calculated spectra indicated that the low-density plasma which fills the cavity makes an important contribution to the X-ray emission in the energy region above ∼500 eV. The rise time of the X-ray emission from the indirectly heated surface is determined by the period of time required to form the radiation-heated zone.
Comparison between Theoretical Analyses and Experimental Results of an ICRF Loading in JT-60
Authors: Hamamatsu Kiyotaka , Saigusa Mikio , Kimura Haruyuki , Fujii Tsuneyuki , Kobayashi Noriyuki , Ikeda Yoshitaka , Azumi Masafumi
Published: February 2005

A cavity resonance of ICRF fast wave was observed in early experiments on the second harmonic ICRF heating in JT-60. The purpose of these experiments was to confirm an antenna-plasma coupling. We discuss the loading impedance of ICRF waves in a linear theory, since the loading condition was in a low-power regime. The experimental results are compared with a numerical analysis of one-dimensional ICRF wave model. Good agreement between the experimental results and the theoretical analysis is obtained qualitatively.
Electroreflectance Studies in CuGaS2
Authors: Shirakata Sho , Murakami Kazuo , Isomura Shigehiro
Published: February 2005

Room temperature electroreflectance (ER) measurements have been performed near the fundamental absorption edge of CuGaS2 single crystals grown by both iodine-transport and melt-growth methods. Transition energies and broadness of the ER spectra are examined and the results are discussed in terms of photoluminescence properties. The band gap energy obtained from the ER spectrum is 2.492 eV at 290 K, and the value is larger than the widely used band gap energy of 2.43 eV determined by the previous ER studies.
Role of Electron Traps on the Thermal Conversion and Its Suppression for Liquid-Encapsulated Czochralski GaAs Single Crystals
Authors: Chichibu Shigefusa , Ohkubo Norio , Matsumoto Satoru
Published: February 2005

Concentration depth profiles of both carrier and electron traps shallower than EL2 are investigated for undoped liquid-encapsulated Czochralski GaAs single crystals after annealing in vacuum and ambient arsenic vapor pressure with As metal powders. Thermal conversion near the surface of semi-insulating GaAs annealed in vacuum at 900°C is suppressed by annealing with ambient arsenic pressure of 100 Torr. The carrier concentration depth profile of thermally converted GaAs, which is an initially semi-insulating substrate, depends not only on the concentration change of EL2 but also on that of native shallow acceptors and deep donors shallower than EL2.
Solid State Growth of CuInSe2 and CuInTe2
Authors: Yamamoto Nobuyuki , Ishida Satosi , Horinaka Hiromichi
Published: February 2005

Solid state growth by sintering, previously successful in growing CuInS2, was applied to the growth of CuInSe2 and CuInTe2. Highly densified and oriented single-crystallike samples so grown were found to have good electrical quality comparable with those grown by the bridgeman or other methods. The existence of order-disorder solid-state phase transition in their phase diagrams is considered to be necessary to prepare such an ordered crystal as is the case with CuInS2.
Electron Mobility in Si Inversion Layers
Authors: Masaki Kazuo , Hamaguchi Chihiro , Taniguchi Kenji , Iwase Masao
Published: February 2005

Gate voltage dependence of electron mobility in n-channel MOSFETs is investigated using Hall effect and channel conductance measurements at room temperature and at 77 K. The electron mobilities obtained by the two different methods show a good agreement with each other and exhibit a decrease with increasing gate voltage in the region of high effective normal field. The theoretical model for electron mobility is given based on the interactions of two-dimensional electron gas confined in the inversion layer with acoustic phonons, intervalley phonons, surface-roughness and ionized impurities. An analytical expression is obtained for the electron mobility, where three types of f- and g-intervalley phonons are included. The calculated results show a good agreement with the experimental data and the decrease in the mobility at high effective normal field is interpreted in terms of surface-roughness scattering which results in E
eff
-2 dependence at high normal fields.
A Numerical Consideration of the Effect of an Antistatic Agent on Electrical Conduction in Polyethylene
Authors: Kaneko Kazue , Suzuoki Yasuo , Mizutani Teruyoshi , Ieda Masayuki
Published: February 2005

The electrical conduction mechanism of high-density polyethylene (HDPE) films which contain an antistatic agent (AS-1) is discussed through a numerical method. The simulations were carried out on a model in which charge carriers were assumed to be electrons injected from the cathode by the Schottky effect and dissociated from donor sites by the Poole-Frenkel effect, and the ionized donor sites were immobile. The calculated currents agreed well with the experimental current-voltage and current-time characteristics. The numerical simulation also showed the anomalous discharge current and the formation of hetero space charge which was found in thermal-pulse-current experiments. This model explained the high-field conduction of HDPE doped with AS-1.
Packing Characteristics of Atomic Structures of Model Icosahedral Phases
Authors: Tei Tetsushoku , Kimura Kaoru , Takeuchi Shin , Mera Yutaka , Maeda Koji
Published: February 2005

Voronoi polyhedra and tetrahedra-octahedra packing analyses have been performed for atomic structures of two types of model icosahedral phases (I-phases), the Mackay icosahedron (MI) type and triacontahedron (TC) type. The structures have been constructed based on the models of Henley and Elser. In the TC-type I-phase, Voronoi volumes can be divided into large and small, and the structure consists mostly of tetrahedral units, indicating that this type of I-phase is a dense packing of two sizes of atoms. In the MI-type I-phase, no distinct separation of the distribution of the Voronoi volumes is seen, and the structure contains a large number of octahedral units, indicating that the MI-type I-phase alloys are not close packings of different-sized atoms. The compositions of existing I-phase alloys are discussed in relation to the above analyses.
Study of the Surface of CdTe Treated in H2 Plasma
Authors: Nishibayashi Yoshiki , Tokumitsu Yoji , Imura Takeshi , Osaka Yukio
Published: February 2005

The surface of CdTe can be cleaned using H2 plasma. Native oxide and thin Te layers on the CdTe surface are removed at a temperature higher than 100°C. The photoluminescence intensity of edge emission became largest as the surface of CdTe was treated in H2 plasma at a temperature of about 100°C. From the intensity of the defect-related emission band in photoluminescence spectra of H2-treated films, it is concluded that the surface treatment of CdTe by H2 plasma at 170°C is most appropriate.
Thickness Determination of LB Films by X-Ray Diffraction
Authors: Okada Shuji , Nakanishi Hachiro , Matsuda Hiro , Kato Masao , Nishiyama Tsutomu
Published: February 2005

X-ray diffraction patterns of amorphous-polymer LB films were investigated in detail, and weak peaks at low 2θ angles were found to correspond to the film thickness. The diffractions are considered to be the results of Fourier transformation of two component systems: one at the interface of air and amorphous film, and the other at that of the film and substrate.
Quantum Size Effect of Semiconductor Microcrystallites Doped in SiO2-Glass Thin Films Prepared by Rf-Sputtering
Authors: Tsunetomo Keiji , Nasu Hiroyuki , Kitayama Haruyuki , Kawabuchi Akira , Osaka Yukio , Takiyama Ken
Published: February 2005

Semiconductors such as CdTe, CdSe and GaAs, microcrystallites could be successfully doped into SiO2-glass films by the magnetron rf-sputtering technique. The average size of the microcrystallites depended on sputtering conditions, and postannealing was not necessary to form microcrystallites in the silica-glass films. The average diameter varied from below 15 A to 62 A. In the optical absorption spectra, the absorption edge of the films clearly exhibited blue shift compared to each bulk semiconductor, and thus the quantum size effect could be found in these microcrystallites.
Photoelectron Emission from the Quartz Surface of an Ultraviolet Lamp under Atmospheric Conditions
Authors: Gosho Yasushichi , Saeki Masamori
Published: February 2005

Photoelectrons are emitted from the quartz surface of an ultraviolet lamp under atmospheric air conditions, and the lamp behaves like an electron emitter. The lamp used in the present experiment is 4 W and has light emission peaks at 185 nm and 254 nm. With this lamp, the emission current of the order of 10-9 A is produced in atmospheric air. This photoemission phenomenon is of great importance to charge elimination of charged matter.
Degradation Behaviour of Fiber Reinforced Plastic under Electron Beam Irradiation
Authors: Sonoda Katsumi , Yamamoto Yasushi , Hashimoto Osamu , Ono Toshio , Tomita Haruhiko , Udagawa Akira , Egusa Shigenori , Sasuga Tsuneo , Seguchi Tadao , Tamura Naoyuki
Published: February 2005

Various mechanical properties of four kinds of glass fiber-reinforced plasrics irradiated with electron beams were examined at three temperatures; room temperature, 123 K and 77 K. Dynamic viscoelastic properties were measured, and fractography by means of scanning electron microscopy was observed in order to clarify degradation behaviour. A considerable decrease in interlaminar shear strength (ILSS) at room temperature was observed above 60 MGy. On the other hand, the three-point bending strength at 77 K and the ILSS at 123 K decreased with increasing irradiation. Fractography reveals that the degradation of the interface layer between matrix resin and fiber plays an important role in the strength reduction at 123 K and 77 K. These findings suggest that the interface between matrix resin and fiber loses its bondability at 123 K arid 77 K after electron beam irradiation.
Transition Radiation Detector with Uniform π/e Rejection Ability
Authors: Fujii Tadao , Fukushima Hiroshi , Kuwano Mitsuhiro , Matsushita Norihiko , Nagai Kouichi , Umetani Youko , Yokoyama Chiaki , Fujiwara Kazuyuki , Takahashi Yoshiki , Homma Yasuhiro
Published: February 2005

We have developed a planar transition radiation detector to be used for electron tagging in the experiment of heavy quark decay. It consists of a radiator of multilayer polypropylene foils and a Xe gas multiwire proportional chamber for X-ray detection. The performance was tested in the mixed π/e beam of several GeV/c range. With four modules of this type, the pion contamination less than 3.5% was achieved at the electron detection efficiency of 90% over the effective area of 55×55 cm2. Some important feature for the stable operation are also discussed.
Spectroscopic Stability in Two-Photon Absorption by Atoms
Authors: Mizushima Masataka , Nakahara Katsuhiko , Yoshida Tadashi
Published: February 2005

When there exists no external field, physical results should not depend on the choice of quantization axis. This theorem is known as spectroscopic stability and is well established for one photon absorption and emission processes. In two photon absorption by a three level atom one can make the excitation of the top level forbidden if the absorption processes are restricted to one selection rule in Δ
M (=+1, 0 or -1). The choice of selection rule assumes relative orientation between the polarization of the radiation field and an external field. If this relative orientation is changed the selection rule would also change and the top level would appear as a final result of two photon absorption . A question is what happens if the external field disappears in the latter case. Would the top level disappear although the selection rule stays unaltered? It is shown that the probability of having the top level disappears when the external field vanishes, confirming the spectroscopic stability and the degree of violation is obtained as a function of the strength of the external field.
Experimental and Analytical Performance of a Pulsed Power Transformer
Authors: Yugami Noboru , Miyamoto Syuji , Umehara Satoshi , Zakou Akira , Imasaki Kazuo , Yamanaka Chiyoe , Nakai Sadao
Published: February 2005

The performance of a pulsed power transformer was investigated theoretically and experimentally at the Institute of Laser Engineering, Osaka University. The pulsed power transformer is a 10:1 step-down transformer. The transformer can decrease the characteristic impedance of the pulsed power machine and the parasitic inductance at the water/vacuum surface. In experiments, a high current pulse (∼1 MA) was obtained. This value was twice as high that obtained when no transformer was used. According to the prototype transformer experiments, the geometry of the secondary coil is of key importance in the design of the transformer. The radiation power (>100 eV) from it was determined to be 20 GW with a 40-ns pulse duration, and the total radiant energy was estimated to be 800 J. According to these experiments and numerical analysis, it is necessary to change the number of turns of the secondary coils to 4 to obtain higher energy efficiency.
N2O-Gas Sensing Using a Gas Polarographic Oxygen Sensor
Authors: Usui Toshio , Asada Akiyoshi , Ishibashi Kohsei , Nakazawa Mitsuhiro
Published: February 2005

N2O-gas sensing in N2O-O2 and N2O-N2 gas mixtures was investigated using a gas polarographic oxygen sensor which was operated at 500°C. The sensor detected the gaseous oxygen formed by the thermal decomposition of N2O; consequently, the output of the sensor agreed well with that calculated on the basis of the assumption that N2O was fully decomposed into O2 and N2 gases.
Multi-Beam Concepts for Nanometer Devices
Authors: Lischke B. , Bennecke W. , Brunner M. , Herrmann K. H. , Heuberger A. , Knapek E. , Schäffer P. , Schnakenberg U.
Published: February 2005

To overcome the throughput limitations in electron beam nanolithography, a multi beam system is proposed. Theoretical considerations show that this e-beam comb-probe printer with 1024 probes will be capable of combining 25 nm resolution with a maximum beam current of 5 µA. This allows an exposure speed of 0.1 cm2/s, which is orders of magnitude superior to today's most advanced equipment. In addition, the multi beam principle is considered for nanometer pattern inspection and for ion-beam techniques. The basic concepts for these applications are presented. Practical feasibility investigations are the subject of current research.
Wafer Cleaning with Photoexcited Chlorine and Thermal Treatment for High-Quality Silicon Epitaxy
Authors: Watanabe Satoru , Sugino Rinshi , Yamazaki Tatsuya , Nara Yasuo , Ito Takashi
Published: February 2005

The authors propose a new photoexcited silicon-wafer cleaning technique, in which ultraviolet light irradiates the wafer through chlorine gas, followed by thermal treatment in a hydrogen ambient, to grow a high-quality epitaxial layer. The surface metal contaminants were removed through a thin native oxide without damaging the surface by photoexcited cleaning, and the remaining volatile chloride after the photoexcited cleaning at 150°C was removed by thermal treatment at 900°C. Further thermal treatment at 980°C removed even the thin native oxide and then made it possible to grow an epitaxial silicon layer. The SiO2 film formed using a conventional technique on the epitaxial silicon layer showed improved breakdown fields and a decrease of fixed-charge density. The results mean that a high-quality silicon-epitaxial layer has been realized by the cleaning procedure.
An MOS-Type Two-Dimensional PSD Using the AC Photovoltage Phase
Authors: Niu Hirohiko , Maeda Miki , Matsubara Yoshihiro , Yoshida Haruhiko , Matsuda Tetsuro , Kishino Seigô
Published: February 2005

A simulation and experiments have been conducted to develop a two-dimensional position-sensitive detector (PSD) from the previously presented MOS-type PSD. The ac photovoltage phase is used as a positional signal for this MOS-type PSD which requires no reverse-bias voltage, being similar to the Wallmark-type or floating-junction PSD. The simulation has been made using a RC network which equivalently represents the PSD; it has been shown that our PSD is useful for two-dimensional photosensing, admitting a light spot even of nonuniform intensity incident on its face. Experiments have demonstrated that the MOS-type two-dimensional PSD of Al-SiO2-Si has good linearity and electrically adjustable sensitivity. A resolution of 1 µm also has been demonstrated for the present PSD equipped with a simple phase-measuring system.
X-Ray Photoelectron Spectroscopy of Pt/GaAs Interfacial Reactions
Authors: Iwakuro Hiroaki , Kuroda Tsukasa
Published: February 2005

Pt/GaAs interfacial reactions were studied by X-ray photoelectron spectroscopy combined with argon ion sputtering. Even at room temperature, the reaction occurred to form a Pt-rich Pt-Ga compound and unreacted As. It was found that Pt interacts with Ga in GaAs at the beginning of the reaction. The top surface of the deposited Pt film was covered with As. Annealing at 200°C formed PtAs2 and the same Pt-Ga compound that was found in the as-deposited state. The top surface was covered with Ga because As and its oxides sublimated during annealing. Annealing at 450°C produced islands of Ga-rich Pt-Ga compound on the sample surface. A ternary compound was formed in the surface region outside the islands.
A New Operation Mode of a Ferroelectric Liquid Crystal Cell with an Asymmetrical Surface Condition
Authors: Yoneya Makoto , Kondo Katsumi , Odamura Motomi , Kitamura Teruo
Published: February 2005

The results of theoretical and numerical analyses are presented for the dynamic behavior of a ferroelectric liquid crystal cell which has two substrates with different surface interaction characteristics. On the basis of these results, a new operation mode is proposed which has bistability between a uniform state and a splayed one. This new operation mode provides both bistability and high image quality in thick (≧4 µm) cells.
Localized States of Cs3Sb Photocathode Materials in Valency Control Experiments
Authors: Hirohata Toru , Ihara Tuneo , Miyazaki Masaharu , Suzuki Toshihiro , Mizushima Yoshihiko
Published: February 2005

Thermoelectric properties are investigated in term of the effect of impurity doping in Cs-Sb photocathodes. The Cs-Sb photocathode is known to incorporate Cs vacancies, which lead to a p-type conductivity. To control the conductivity of the Cs-Sb photocathode, we have doped divalent alkaline-earth atoms, and measured the conductivity type. The result is contradictory to the conventional concept, and is conveniently interpreted as indicating that the Cs-Sb photocathode does not have a single-crystalline band structure but an amorphous like one.
Electron Energy Distribution in Multicusp-Type ECR Plasma
Authors: Amemiya Hiroshi , Ishii Shigeyuki
Published: February 2005

A multicusp-type electron cyclotron resonance (ECR) plasma device is built with SmCo magnets and 2.45 GHz, TE11 circular-mode microwaves. DC bias can be superimposed between anode bars and a grid placed near the end surface to control the plasma. Electron energy distribution is measured by a Langmuir probe and a gridded analyzer. The plasma density is about 2×1010 cm-3 and 4×1010 cm-3 at the center and the cusp region, respectively. The equivalent electron temperature, 2/3 times the mean energy, is 4 eV and 15 eV at respective regions. The high-energy tail extends to above 100eV.
Real-Time Interferometric Spectrometer by Spatial Band-Pass Filtering Detection
Authors: Okamoto Takayuki , Yamaguchi Ichirou
Published: February 2005

An interferometric spectrometer which delivers a spectral power in real time without Fourier transform calculations is described. In this spectrometer, an interferogram is generated by a two-beam interferometer as a spatially distributed pattern on an array detector. This array and a following electronic circuit construct a spatial band-pass filter which transmits a spectral component at a desired wave number. The wave number can be changed by moving a mirror in the interferometer. This spectrometer is handled as easily as a grating spectrometer, whereas the throughput advantage is retained. The emission spectra of a He-Ne laser and a low-pressure mercury lamp driven by AC current are measured to demonstrate the spectrometer performance.
Depth Profiling of the Electronic Structure of a Mica by Low-Energy Electron Energy Loss Spectroscopy
Authors: Moore Stephen , Shimizu Hiroshi , Masuda Akimasa , Tadami Yasushi , Koma Atsushi
Published: February 2005

Low-energy electron energy loss spectroscopy (LEELS) has been used to study the electronic structure of margarite. The results show that the electronic structure of margarite is determined principally by local atomic arrangement and also the usefulness of LEELS as a powerful technique to investigate the depth profiling of the electronic structure of a material.
A Theoretical Consideration of the Waveform in the Cu/CuCl Vapor Laser Output
Authors: Taniguchi Hiroshi , Saito Hiroshi
Published: February 2005

An oscillatory waveform (undulation) was observed in the 510.6 nm laser line of a discharge-pumped CuCl vapor laser. Either an oscillatory or a nonoscillatory phenomenon appeared, depending on the operating temperature of the laser. This paper describes an analysis of the laser waveforms using a small-signal approximation of the rate equations in the lasing system. It is shown that the undulation is due to the relaxation oscillation.
Removal of a Thin SiO2 Layer by Low-Energy Hydrogen Ion Bombardment at Elevated Temperatures
Authors: Miyake Kiyoshi
Published: February 2005

Low-energy (0.5, 1.0 keV) hydrogen ion bombardment at elevated temperatures (450–500°C) was shown to be useful as a surface cleaning method to remove a thin oxide layer (presumably SiO2) on Si substrates. In situ Auger electron spectroscopy (AES) analysis indicated that the SiO2 layer dissociated under the presence of ion implanted hydrogen at elevated temperatures. Neither hydrogen ion bombardment at room temperature (RT) nor postannealing after the RT ion bombardment had any removal effect regarding the oxide layer. By comparison, He+ ion bombardment, combined with postannealing at 500°C, produced a Si-rich SiO
x
surface, but the surface oxide could not be removed completely. Consideration of hydrogen and helium ion bombardments indicated that a chemical sputtering effect caused by the ion implanted hydrogen atoms in SiO2 played a significant role in the removal of SiO2.
Linewidth Measurement by a New Scanning Tunneling Microscope
Authors: Yamada Hirofumi , Fujii Toru , Nakayama Kan
Published: February 2005

We have developed a new STM using monolithic parallel spring mechanisms with fiexture hinges. The STM is equipped with a two-dimensional optical interferometer to calibrate the motion of the scanner with subnanometer accuracy in real time. Distortion-free images of a grating pattern have successfully been observed.
Improvement of Luminous Efficiency in ZnS:Tb, F Thin-Film Electroluminescent Devices Using Ferroelectric PbTiO3 and Silicon Nitride as Carrier Accelerating Buffer Layers
Authors: Fukao Ryuzo , Fujikawa Hisayoshi , Hamakawa Yoshihiro
Published: February 2005

Thermal carrier accelerating action and its effect on electroluminescence performance by insertion of a buffer layer have been systematically studied in ZnS:Tb, F thin-film electroluminescent (EL) devices. The EL devices studied have a structure of ITO/PbTiO3/ZnS:Tb, F/SiNx/Al. The result shows that the brightness obtained is rather low, but luminous efficiency is high compared to that of EL devices without an SiNx buffer layer. A mechanism for the improvement of luminous efficiency is postulated, and the role of the buffer layer is also discussed.
Direct Solution of the Landau-Lifshitz-Gilbert Equation for Micromagnetics
Authors: Nakatani Yoshinobu , Uesaka Yasutaro , Hayashi Nobuo
Published: February 2005

A mathematical framework is presented for solving the Landau-Lifshitz-Gilbert equation expressed in Cartesian components of magnetization according to the backward difference method without conflicting with the constraint of constant magnetization. Test calculation shows that the method allows the use of a large time step almost independent of spatial mesh size and damping constant. The derived program is used to calculate the magnetization structure of a crosstie wall in a Permalloy film yielding calculated structures which closely resemble the electron-holography image of an actual cross-tie wall. It is also used to investigate magnetization reversal mechanisms in fine ferromagnetic particles by pursuing time dependent changes in magnetization structures. The paper gives detailed descriptions of the reversal mechanisms which differ depending on the size of the particle.
Large Illumination Memory in an Organic Photoreceptor Coated on an Organic Metal Electrode
Authors: Nakazawa Yusuke , Hoshino Katsuyoshi , Hanna Jun-ichi , Kokado Hiroshi
Published: February 2005

A remarkable photo-induced illumination memory was observed in an iodine-doped conductive polymer/poly(N-vinylcarbazole) (PVK)-trinitrofluorenone (TNF) double-layered system. The memory was measured as a lowering of charge acceptance and investigated as a function of various parameters such as the wavelength, the intensity and the exposure of incident light. It was found that the interface between the conductive polymer containing iodine and the photoconductor is responsible for this phenomenon and the memory effect is caused by carriers generated in the photoconductor. The exposure needed for lowering the charge acceptance to half the initial value was about 30 µJ/cm2. The memory effect was also observed in an organic iodide-dispersed PVK/TNF system though its sensitivity was much lower than that of the aforementioned polymer-using system.
Structural Differences between Al-Fe-Cu and Al-Li-Cu Quasicrystals Studied by High-Resolution Electron Microscopy
Authors: Hiraga Kenji , Shindo Daisuke
Published: February 2005

Stable icosahedral phases of Al-Fe-Cu and Al-Li-Cu, which are recognized as icosahedral quasicrystals corresponding to face-centered and simple 6D-hypercubic lattices, respectively, were examined by high-resolution electron microscopy with the incident beam parallel to the two-fold symmetry axis. Images observed were analyzed in detail with the aid of computerized image processing. In the image of Al-Li-Cu, a contrast modulation of about τ3 times distance of lattice spacing was observed on lattice fringes perpendicular to the 5-fold symmetry axes, whereas in Al-Fe-Cu, complex contrast modulations with various distances of 2, 3, and 5 lattice spacings were observed on the lattice fringes perpendicular to the same axes.
AES Study of the Reaction between a Thick Fe-Film and β-SiC (100) Surface
Authors: Mizokawa Yusuke , Nakanishi Shigemitsu , Miyase Sunao
Published: February 2005

The solid state reaction between a thick Fe-film and β-SiC (100) surface in UHV has been studied using AES in conjunction with ion sputtering. Upon annealing of the thick-Fe-film/SiC at 250°C, only the C-atoms diffused to the film surface and exhibited a Fe3C feature. During a 540°C anneal, the Si-atoms also segregated at the surface through grain boundary diffusion and formed the elemental-Si and the Fe-silicide phase. The depth profile showed that the atomic ratio among silicide, Fe3C, graphite and unreacted-Fe in the film was approximately 1:2:0.8:15, indicating a limited reaction. Big pile-ups of both Fe3C and elemental-Si were detected at the Fe-SiC interface, which suggests that the Fe3C acts as a reaction barrier and prevents the free Si-atoms from diffusing into the Fe-film.
Resistivity Correction Factor for the Four-Circular-Probe Method
Authors: Yamashita Masato , Enjoji Hideo
Published: February 2005

A method which improves the accuracy of calculation of the resistivity correction factor (RCF) is described. The method is applied to a system which consists of a rectangular parallelepiped sample and a four-circular-probe array. The current probes are replaced by the equivalent current source and sink (ECSS). The ECSS is derived on the basis of the interactions associated with the current probes and the images. The average potentials are used as the potentials of the voltage probes. Numerical evaluations show that the images have an important contribution to the RCF. The method is useful in obtaining the specific contact resistance of a metal-semiconductor contact.
Microstructure and X-Ray Study of Preferentially Oriented SnO2 Thin Film Prepared by Pyrohydrolytic Decomposition
Authors: Fujimoto Masayuki , Urano Tetsuya , Murai Syunji , Nishi Yuuji
Published: February 2005

Preferentially oriented SnO2 thin films were prepared by pyrohydrolytic decomposition onto a glass substrate along the direction of flux flow. The obtained films were oriented in [200] and then [002] directions along the direction of flow. To reveal the orientation mechanism from the initial stage of growth, [200]-oriented SnO2 thin film was prepared on a chemically stable GaAs single crystal. The successive growth structure of the thin film on the substrate was accurately observed and characterized using HR-AEM (high-resolution analytical electron microscopy). A layer of nuclei about 50 Å in width was observed between the GaAs substrate and the oriented overgrown layer. It is suggested that such preferential nucleation occurs from an early stage of growth, and is strongly dependent on supersaturation of the flux flowing along the substrate.
Time Sequential Measurement of the Precursor State of Oxygen on the Titanium Surface by Means of Time-of-Flight Spectroscopy for Electron Stimulated Desorption
Authors: Ueda Kazuyuki , Takano Akemi
Published: February 2005

An adsorption process of oxygen on the titanium single-crystal surface of (101̄0) has been investigated by means of a time-of-flight spectrometer for the electron stimulated desorption (ESD). An oxidation experiment has been performed at the oxygen pressure ranging from 1 to 8×10-8 Torr. TOF spectra of ESD signals were obtained sequentially by a digital acquisition system. In an initial adsorption stage, the O+ ESD signal intensity grew depending on the oxygen exposure. The O+ signal peaks have the most probable kinetic energies of 3.5±0.4 eV and 1.8±0.2 eV. The higher-energy peak is identified as the ESD signal from molecularly adsorbed oxygen on the surface, and the lower one as that from the chemically adsorbed oxygen.
Pressure-Composition Isotherm in a Magnetic Field for the Metal-Hydrogen System
Authors: Yamamoto Isao , Yamaguchi Masuhiro , Kobayashi Tatsuya , Goto Tsuneaki , Miura Shigeto , Mogi Iwao
Published: February 2005

The pressure-composition isotherm under the influence of a magnetic field has been observed for the first time using the LaCo5-H system at 273.20±0.03 K in 12 T.
Device for Quick Evaluation of Meissner Effect
Authors: Takashima Masayuki , Kumatoriya Makoto , Fukami Shinji , Unishi Terunobu , Kano Gentaro
Published: February 2005

A convenient device named MEED (Meissner effect evaluating device) has been developed. This is capable of easily detecting the onset transition temperature (T
onset), and estimating the relative amount of a superconducting phase. The measured T
onsets were in agreement within ± 0.5 K with those measured by the dc 4-probe method. The MEED is useful for a quick evaluation of the superconducting properties of many samples.
A Study of a Surface-Type Positive-Ion-Neutral Converter with Oblique Incidence
Authors: Kawata Jun , Ohya Kaoru , Mori Ichiro
Published: February 2005

The effect of oblique incidence is investigated for the improvement of a surface-type ion-neutral converter for a keV neutral particle source, by using the TRIM85 Monte Carlo code. The emitted particle energy becomes higher and the energy width sharper than those for normal incidence. The angular divergence is largely improved in the area including the incident beam, although it tends to be large in another area perpendicular to it.
The Phase Transition Pressures of Zincsulfoselenide Single Crystals
Authors: Tiong Shirley R. , Hiramatsu Makoto , Matsushima Yasushi , Ito Eiji
Published: February 2005

The static phase transition points of ZnSe and ZnSe
x
S1-x
(0.40 ≤ x ≤ 1) single crystals in the high pressure region are determined based on the transformation pressures of Bi I-II, Bi III-V, and ZnS using the cubic anvil method where the pressure-induced variation of resistance is measured. The transition pressures of the samples vary almost linearly with the composition of ZnS in ZnSe
x
S1-x
.
An Improved Optical Lever Technique for Measuring Film Stress
Authors: Aoki Takeshi , Nishikawa Yasuo , Kato Seiichi
Published: February 2005

This letter describes a simple and accurate method of measuring film stress. This method differs principally from the conventional optical lever method in utilizing two parallel beams instead of translating a sample. The apparatus assembled experimentally demonstrates a detectable deflection of the sample on the order of 1 µm.
Electrical Properties of Heteroepitaxial Ge Films on Si(100)–2×1 Surfaces
Authors: Kataoka Yohichi , Hida Yuuhiro , Ueba Hiromu , Tatsuyama Chiei
Published: February 2005

Electrical properties of epitaxial Ge films grown on Si(100)–2×1 surfaces have been studied by Hall measurement, and their structural properties have been characterized by analyses of LEED patterns, X-ray diffraction, Raman scattering spectra and cross-sectional TEM images. It has been found that the growth layers exhibit p-type conduction, possibly due to the Ge vacancies and the temperature dependences of carrier concentration n(T) and hole mobility µ(T) depend on growth conditions, such as substrate temperature, film thickness and annealing treatment. For thick Ge films grown on coalesced Ge islands, µ(T) is governed by long-range optical phonon scattering, indicating the growth of high structural quality in the Ge films. For relatively thin films composed of Ge islands, on the other hand, µ(T) obeys short-range acoustic phonon scattering due to crystalline imperfections, such as dislocations or defects. Similar experiments have also been performed for thin Ge films grown on predeposited Ge buffer layers on Si substrates.
The ac Magnetic Response of Superconducting YBa2Cu3O7-x
Authors: Sato Masaki , Kamimura Takashi , Iwata Takao
Published: February 2005

The nonlinear magnetic response of a high-T
c superconductor YBa2Cu3O7-x
has been investigated by the ac induction method. At temperatures below 80 K, the fundamental and the third-higher harmonic susceptibility components of both the pellet and coarse powder samples strongly depends on the field amplitude. Also, M-H curves exhibit a hysteresis which bears a similarity to that of hysteretic superconductors. These characteristics are absent in well-isolated particles. Around the transition temperature, susceptibility components have a behavior distinct from that at low temperature and the magnetic response is nearly reversible. The observed magnetic behavior is interpreted as a superposition of the bulk property and the effect of weak linkage of superconducting particles.
Hysteresis Losses in a Type-II Superconductor in the Regime of Reversible Fluxoid Motion
Authors: Matsushita Teruo , Harada Naoyuki , Yamafuji Kaoru , Noda Minoru
Published: February 2005

The hysteresis losses due to ac magnetic fields are measured for a bulk superconducting Nb-Ta tape in the regime of reversible fluxoid motion under a bias field. The observed hysteresis losses and power factor agree well with the theoretical estimate based on Campbell's model of the force-displacement characteristic of the fluxoids. The hysteresis losses in superconducting multifilamentary wires with very fine filaments are also estimated from this scheme.
Effects of Oxygen Ion Implantation on the Conduction Electron Spin Resonance in Aluminum
Authors: Nishida Akihiko , Horai Kazumi , Fujita Tetsuo
Published: February 2005

Changes induced by oxygen implantation in the temperature dependence of the linewidth, g value and peak height of CESR in aluminum foils were investigated, using the spin transmission technique. It was found that oxygen implantation induces excess conduction-electron-spin relaxation, which takes maxima at 7 K and 77 K. The results were analyzed by Hasegawa's model incorporating the Kondo effect. The excess relaxation was simulated fairly well by “resonant Kondo scattering” with two kinds of impurity states. Both the g value and peak height revealed a large contribution to interzone scattering at the Fermi surface from complex localized surface states. Based on detailed observations, the existence and contribution of localized moments at the Al/AI2O3 interfaces with oxygen implantation are suggested.
Increase in Impurity in Single Bunch Mode of UVSOR Storage Ring
Authors: Kasuga Toshio , Yonehara Hiroto , Hasumoto Masami , Kinoshita Toshio
Published: February 2005

An increase in impurity was observed in the single bunch mode of the UVSOR storage ring. Electrons in RF buckets following the single bunch increase with time after the electron beam injection. This phenomenon is caused by electrons thrown out of the bucket by the Touschek effect being captured again by following buckets due to radiation damping. The qualitative explanation is satisfactory and the quantitative estimation of the rate of the impurity increase is reasonable.
AC Conductivity of Undoped a-Si:H and µc-Si:H in Connection with Morphology and Optical Degradation
Authors: Yamazaki Motoharu , Nakata Jun-ichi , Imao Shozo , Shirafuji Junji , Inuishi Yoshio
Published: February 2005

Ac conductivity of a-Si:H and µc-Si:H films is studied experimentally with theoretical consideration. By separating ac conductivity into band, variable range hopping (VRH), band tail multiple hopping and intimate pair hopping conductivities, the effects of the morphology and optical degradation in each type of the conductivities were investigated to elucidate the nature of electronic conduction. Experimental facts on the pair-hopping conductivity seem to be explained in terms of a two-electron correlated barrier hopping (CBH) model between oppositely charged dangling bond pairs located at low-density Si–H alloy regions (voids). Long-range transport (band, multiple hopping, VRH) seems to be related to the percolation through Si clusters and microcrystalline grains, being sensitive to the morphology and Fermi level position.
Dimensional Crossover of Electron-Electron Scattering in GaAs-AlGaAs Wires
Authors: Takagaki Yukihiko , Ishibashi Koji , Ishida Shuichi , Takaoka Sadao , Gamo Kenji , Murase Kazuo , Namba Susumu
Published: February 2005

We report a size effect on the phase coherence length (Li) in narrow GaAs-AlGaAs wires, deduced from the negative magnetoresistance due to weak localization. The temperature dependence ofLichanges as the channel width becomes narrower than the thermal diffusion length. We interpret the change as a dimensional crossover of the electron-electron scattering. The deducedLican reasonably explain the amplitude of Aharonov-Bohm magnetoconductance oscillations observed in a ring fabricated from the same wafer.
Cellular Pattern Formation in Detonation Waves as a Stochastic Phenomenon
Authors: Terao Kunio , Azumatei Tatsuo
Published: February 2005

Using a shock tube, detonation waves of different strengths were produced in a stoichiometric propane-oxygen mixture and the cellular patterns marked on soot films were statistically investigated. From the histograms of the interval distance between two successive “triple shock collision points” the probability of formation of the triple shock collision point under different conditions was obtained and compared with the probability of spontaneous ignition in the same mixture obtained from the induction period of ignition behind reflected shock waves in a shock tube. The results suggest that the cellular patterns in the detonation waves are formed not by the triple shock collision in the concept of gas dynamics, but by the spontaneous ignition behind the shock waves at the detonation front accompanied by the isochoric combustion.
The Dielectric Relaxation of a Copolymer of Vinylidene Fluoride and Trifluoroethylene
Authors: Miyashita Satoru
Published: February 2005

Dielectric relaxation of a ferroelectric copolymer of vinylidene fluoride and trifluoroethylene is analyzed using Skinner's soliton model. In the paraelectric phase, the model can reproduce the dielectric relaxation spectra; the soliton in this phase is in the intermediate state between the ballistic and the diffusive limit. The formation energy of the soliton is 10 kcal/mol and the formation enthalpy of the defect is 6.0 kcal/mol. In the ferroelectric phase, this model cannot reproduce the dielectric loss spectra. It is found that the effects of the dipole correlation and asymmetric crystal field potential should be taken into account.