bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Functional, Resonant-Tunneling Hot Electron Transistor (RHET)
Authors: Yokoyama Naoki , Imamura Kenichi , Muto Shunichi , Hiyamizu Satoshi , Nishi Hidetoshi
Published: November 2005

Abstract-A new functional, resonant-tunneling hot electron transistor (RHET) is demonstrated in which electrons are injected from emitter to base by resonant-tunneling through a quantum well, and are near-ballistically transferred to a collector. The main feature of this device is a peaked collector-current characteristic with respect to the base-emitter voltage. This enables us to build a frequency multiplier or an Exclusive-NOR gate using only one transistor.
Pulsed CO2 Laser Pumped by an All Solid-State Magnetic Exciter
Authors: Shimada Tsutomu , Noda Kohji , Obara Minoru , Midorikawa Katsumi
Published: November 2005

An all solid-state exciter, which consists of a Silicon Controlled Rectifier (SCR) switched pulse transformer and a three stage magnetic pulse compressor, has been successfully used for pulsed CO2 laser excitation. By the present exciter, an output laser energy of 240 mJ has been obtained at 1 pps under sealed-off conditions. Since this laser has no discharge switch, long lifetime operation with high repetition rate (HRR) is anticipated.
Photoconductivity and Photoacoustie Spectra of Trigonal, Rhombohedral, Orthorhombic, and α-, β-, and γ-Monoclinic Selenium
Authors: Nagata Kiyofumi , Miyamoto Yasuhiko , Nishimura Hideki , Suzuki Hiromichi , Yamasaki Satoshi
Published: November 2005

Photoconductivity and photoacoustic spectra of all known crystalline allotropes of selenium have been measured. Both the photocurrent peaks and the absorption edges have a tendency to shift monotonously to lower energy region with the increase in density, even though the constituents of the crystals are different, suggesting that the band gap decreases with the increase in intermolecular interaction.
Nondestructive and Noncontact Observation of Microdefects in GaAs Wafers with a New Photo-Thermal-Radiation Microscope
Authors: Nakamura Hiromichi , Tsubouchi Kazuo , Mikoshiba Nobuo , Fukuda Tsuguo
Published: November 2005

A nondestructive and noncontact method for observation of microdefects in GaAs wafers has been developed with a new photo-thermal-radiation (PTR) microscope. We measured the PTR signal as a function of excitation energy (PTR spectrum) and the spatial distribution of PTR intensity (PTR image) of n-GaAs wafers at room temperature. We found that the PTR spectra have a peak due to a nonradiative state of microdefects at wavelengths ranging from 895 to 903 nm. The present PTR image shows inhomogeneities of microdefect density in GaAs wafers which cannot be observed by X-ray topography.
Single-Longitudinal-Mode Selfaligned (AlGa)As Double-Heterostructure Lasers Fabricated by Molecular Beam Epitaxy
Authors: Tanaka Haruo , Mushiage Masato , Ishida Yuhzi , Fukada Hayami
Published: November 2005

Single-longitudinal-mode selfaligned (AlGa)As double-heterostructure (DH) lasers were fabricated by two-step molecular beam epitaxial technique. The AlGaAs surface was protected by a GaAs thin layer during the photolithographic process. The GaAs was thermally etched selectively just prior to regrowth in the MBE system. There was no problem associated with the regrowth of AlGaAs using this GaAs passivation technique. The room temperature CW threshold current for a device with a 200 µm-long and 3 µm-wide stripe was 40 mA. The emission wavelength was 780 nm and a fundamental transverse mode was achieved.
Phase Locking of Semiconductor Lasers Using Homodyne Detection and Negative Electrical Feedback
Authors: Wenke Gerhard , Saito Shigeru
Published: November 2005

Investigations of an optical phase locked loop using semiconductor lasers and homodyne detection are reported. The phase noise in the phase locked loop, that is, the fluctuatin of phase difference between the slave and master laser is measured under free running and locked conditins. Strong phase noise reduction has been observed under locked condition. The measured results are in reasonable agreement with calculated results applying the linear transfer function of a phase locked loop.
Color Gamut of Blackness in a Liquid Crystal Display
Authors: Shimomura Teruo , Kobayashi Shunsuke
Published: November 2005

A guest-host mode liquid crystal display of a transmission type is investigated. Color gamut of blackness is established from an estimation experiment of color matching and is shown by the CIE 1931 chromaticity diagram and color solid. Color gamut of blackness under the influence of a light source and ambient illumination is discussed. A Munsell color ship, N-1 is used as a matching black color sample and fifty hues of liquid crystal cells are used as test sample colors. Six observers participate in the estimation experiment and measurement is done from ascending- and descending-series in the method of adjustment.
Homoepitaxial Growth of InSb by Vacuum Metal-Organic Chemical Vapor Deposition
Authors: Sugiura Osamu , Matsumura Masakiyo
Published: November 2005

Homoepitaxial growth of InSb using metal-organic vapor under a total gas pressure of about 10-3 Torr has been investigated. Single crystal films with smooth surface were obtained at substrate temperatures of as low as 400°C. The conduction type and impurity density of the epitaxial layer evaluated by Metal-Oxide-Semiconductor Capacitance-Voltage (MOS C-V) method were p-type and 2×1015 cm-3, respectively, at 77 K.
Atomic Migration of Metals in the Interfaces of Au-Si and Ni-Si for Crystalline and Amorphous Si Observed by 40 MeV-O5+ Ion Backscattering
Authors: Takita Kôki , Itoh Hisayoshi , Murakami Kouichi , Masuda Kohzoh , Kudo Hiroshi , Seki Seiji , Yamanaka Mitsuyuki , Takada Ryoji , Tomonari Shigeaki , Saito Takashi , Hayashi Yutaka
Published: November 2005

Atomic migration of metallic atoms in the interfaces of Au-Si and Ni-Si is investigated with emphasis on the difference among c-Si, a-Si:H/c-Si and a-Si:F:H/c-Si. 40 MeV-O5+ ion backscattering spectra of the Au-Si system heat-treated at 350°C for 30 min indicate that Au atoms of more than 1020cm-3 were distributed in Si up to a depth of about 1 µm and 3 µm for a-Si:F:H/c-Si and a-Si:H/c-Si, respectively. Because the thickness of a-Si is about 5000 Å, this means that a large amount of Au migrated not only in the a-Si film but also into the substrate of c-Si even below the eutectic point, while Au-migration was not observed in the case of direct contact interface between Au and c-Si.
High Energy Ion Channeling Study of MBE-Grown GaAs(001) Surface Structures
Authors: Narusawa Tadashi , Kobayashi Keisuke L. I. , Nakashima Hisao
Published: November 2005

We have applied the MeV He+ ion channeling technique to study the atomic structure of MBE-grown GaAs(001) surfaces. The inherent sensitivity of our technique to small displacements of surface atoms shows that the As-stabilized GaAs(001)-c(4×4) surface structure contains significant lateral displacements of the first layer As atoms, which are associated with subsurface strain extending down to at least the 4th atomic layer. In contrast, the hydrogen-saturated (1×1) surface has a bulk-like atomic structure.
VPE Growth of ZnS Incorporating Indium on GaP
Authors: Goto Hideo , Zhou Jun , Sawaki Nobuhiko , Akasaki Isamu
Published: November 2005

In the hetero-epitaxial growth of cubic ZnS on a GaP(100) substrate using an open-tube method with hydrogen gas, it was found that the incorporation of indium greatly improved the surface morphology of the ZnS epitaxial layer. The role of indium in the growth kinetics has been studied. The concentration of indium was estimated to be 1018-1019 cm-3. Photoluminescence measurements showed that the incorporation of indium reduced some of the defects that had caused emission peaking at 470 nm.
Selective Acceleration of NBI-injected Fast Ions by Ion Cyclotron Wave in a Tokamak Plasma
Authors: Murakami Yoshiki , Itami Kiyoshi , Ishida Shin-ichi , Suzuki Nobuharu , Hamaguchi Satoshi , Yamada Hiroshi , Nihei Hitoshi , Morikawa Junji , Yoshida Zensho , Inoue Nobuyuki
Published: November 2005

The acceleration of NBI-injected fast ions by ICRF waves has been studied in the TORIUT-5 tokamak. The velocity distribution of fast ions has been measured by a neutral-particle analyzer. The number of fast ions with energies higher than the injected energy is found to be increased by the ICRF acceleration effect. The experiment is consistent with numerical simulations.
Construction of a Highly Sensitive Spectrometer in the Visible Region
Authors: Kuga Takahiro , Shimizu Tadao , Ueda Yoshifumi
Published: November 2005

A sensitive spectrometer was constructed in order to observe very weak visible absorption lines of molecules using a ring dye laser, a multiple-pass absorption cell, and a Stark modulation technique. The minimum detectable absorption coefficient is 3×10-9/cm and is limited by excess laser-radiation noise of the ring dye laser.
This system has been successfully applied for the observation of very weak overtone transitions of NH3 with Δv=5.
Helium Irradiation Effect on Hydrogen Isotope Permeation in Austenitic Stainless Steel
Authors: Terasawa Mititaka , Fukushima Kimichika , Nakahigashi Sigeo , Ebisawa Katsuyuki , Iimura Masashi
Published: November 2005

Pre- and simultaneous-irradiation effects on the D permeability of Type-316 stainless steel were investigated using a dual ion-beam irradiation facility. In the He pre-irradiation experiment, the relative D permeation rate decreased to about 0.3 under backward He++ irradiation and increased to about 3 under forward He+ irradiation for a He fluence higher than 2×1017 He/cm2. By a numerical analysis, the change in the permeation rate was found to be mainly attributable to a diffusion-constant reduction in the He-implanted region. In a simultaneous D+ and backward He++ irradiation experiment, a rapid D permeation rate change occured, probably due to an instantaneously induced D diffusion barrier in addition to the gradual change of the premeation rate similar to that shown in the He backward pre-irradiation experiment.
Radiation Damage Evaluation in Excimer Laser Beam Irradiation and Reactive Ion Etching
Authors: Sekine Makoto , Okano Haruo , Yamabe Kikuo , Hayasaka Nobuo , Horiike Yasuhiro
Published: November 2005

In the course of studying UV-light excited etching, it was found that high-energy ArF excimer laser (193 nm, 6.4 eV) irradiation induced neutral electron traps in a SiO2 film of a MOS capacitor. The trap generation origin was verified to be the excitation of impure OH and Si bonds by the irradiation of an ArF laser beam propagated in the SiO2 film under a poly-Si electrode. It is proposed that Si ions, which released OH radicals during laser irradiation, act as electron traps.
Furthermore, by manufacturing MOSFETs, RIE and ArF laser-irradiation damage was compared. Persistent damage induced during RIE on gate material was found to remain to the last.
Comparison of Microstructure of Cross-Sectional CoCr Thin Film Specimens Prepared by Fracture, Microtome, and Ion-Beam Thinning Methods
Authors: Futamoto Masaaki , Honda Yukio , Shimotsu Teruho , Kakibayashi Hiroshi , Yoshida Kazuetsu
Published: November 2005

Cross-sectional CoCr thin film specimens prepared by three different methods; fracture, ultra-microtome and ion-beam thinning, are observed by electron microscopes to investigate the differences in the microstructure revealed in the respective micrographs. It is shown that the specimen prepared by the ion-beam thinning method provides most detailed and clear crystallographic features of the film structure.
Effect of Heat Treatment in Zn Vapor on the Electrical Properties of ZnO Single Crystals Containing Tri-Valent Donor Impurities
Authors: Kanai Yasuo
Published: November 2005

By a heat treatment in Zn vapor, the electron density of ZnO crystals containing tri-valent donor impurities increases to about twice the value of as-grown crystals. This effect has been interpreted as the result of the occupation of Zn vacancies in as-grown crystals by Zn atoms.
An Application of the Dry Liftoff Method by Molybdenum Oxide Sublimation to CMOS Isolation
Authors: Yamauchi Noriyoshi
Published: November 2005

A CMOS isolation process using a dry liftoff is proposed in which a sputter-deposited SiO2 film is delineated by removing the Mo pattern underneath the SiO2 film making use of the sublimation of the molybdenum oxide. Test CMOS transistors were fabricated. No significant differences were observed in the characteristics of transistors fabricated by dry- and conventional wet-liftoff techniques.
Densimetry of Amorphous Silicon Films by Using a Quartz Oscillator
Authors: Tatsumi Yukichi , Ohsaki Hisashi , Kurahashi Yukio , Iijima Minoru , Kurumi Kaoru , Miura Kouji , Ino Tadashi
Published: November 2005

By using a quartz oscillator with one side of the quartz crystal optically polished, both the weight and thickness of the same film can be measured. With this method a film can be deposited on one part of one side of a quartz oscillator; thus, it is necessary to estimate the frequency constant N by Ag and Au films. As a result, N was found to be 1.86±0.10×105 Hz·cm, a 12% increase over the nominal frequency constant of an AT-cut quartz oscillator. The density of an amorphous silicon (a-Si) film deposited on an Au film was determined to be 1.71±0.09 g/cm3; the density was 27% less than the density of crystal Si. From the result of high-resolution electron micrographs, it is clear that the cause for the low density is not due to such defects as cracks, pores or voids over 2 nm.
Annealing of Supersaturated Low-Temperature Substitutional Gold in Silicon
Authors: Morooka Masami , Tomokage Hajime , Yoshida Masayuki
Published: November 2005

An annealing experiment of supersaturated low-temperature substitutional gold in silicon was made by an ordinary annealing method. The gold concentration was determined from the resistivity by a four-point probe method, the Hall coefficient and DLTS with no appreciable difference in the results. The dependences of the annealing characteristics upon the temperature and the initial value of the gold concentration were examined. The annealing was represented by a firstorder reaction and the time constant decreased with an increase in the initial value.
From these results, it was concluded that homogeneous nucleation occured during the annealing and that a strain energy of low-temperature substitutional gold decreased with nucleus formation.
A Study on Carrier Traps in Plasma-Polymerized Phenylacetylene
Authors: Inoue Masumi , Takai Yoshiaki , Mizutani Teruyoshi , Ieda Masayuki
Published: November 2005

The energy distribution of carrier traps and the photodetrapping process of carriers in plasma-polymerized phenylacetylene (P-PPA) were investigated. The carrier traps were found to be distributed from 1.06 eV below the conduction band and their density increased with the energy depth. Using this trap distribution, the light-intensity dependence of the photocurrent was explained by the Rose model. The carrier detrapping process was understood by applying the Onsager theory. The characteristic thermalization length was estimated to be 1.7 nm.
Fabrication of NbN Josephson Tunnel Junctions and Their Application to DC-SQUIDs
Authors: Matsuda Mizushi , Kuriki Shinya , Nagano Yasushi
Published: November 2005

We have fabricated all hard metal NbN/NbN tunnel junctions. The low dielectic constant of a plasma oxidized a-Si barrier leads to low-capacitance junctions (3 µF/cm2) which are suitable for SQUID applications. Then, planar dc-SQUIDs have been fabricated with NbN junctions. Higher modulation voltages, as high as 90 µV, with an applied flux were obtained for the SQUIDs with larger values of the product of the critical current and the shunting resistance. Effects of a damping resistance across the loop inductance have also been examined.
Magnetization and Uniaxial Anisotropy Measurements for He+ and H2
+ Implanted Garnet Filmus
Authors: Okada Osamu , Honda Hiroko
Published: November 2005

Magnetization measurements using a vibrating-sample-magnetometer for helium and hydrogen implanted garnet films were carried out up to the Curie temperature. Using these data, the uniaxial anisotropy was also deduced by FMR. The magnetization and absolute value of the uniaxial anisotropy for helium-implanted films decrease more markedly at high temperatures, compared with the values for hydrogen-implanted films. It is shown from the normalized magnetization values that the defects created by hydrogen implantations might be smaller than those created by helium implantations. The differences in the bubble operation limits at high temperatures between helium and hydrogen implantations can be attributed to these different magnetic properties for helium- and hydrogen-implanted films.
Evaluation of Radiographic Images by Using Sequential Dependency
Authors: Uchida Suguru , Tsai Du-Yih
Published: November 2005

A method for measuring the overall quality of radiographic images by means of a sequential dependency is presented. In order to relate the quantitative measurements calculated by the sequential dependency to the perceived quality of radiographic images, the term “recognizability” is used. Recognizability is expressed by the degree to which an image can be visually recognized from the points of view of uniformity, symmetry, sharpness and structure. Applications of the method for evaluating radiographic films and for comparing normal and abnormal tissues of esophageal lumen are discussed. The measurements indicate a good agreement between theoretical and visual results.
The Deformation Potential Constant of the Conduction Band in InSb
Authors: Tsukioka Kunio
Published: November 2005

The electron mobility in InSb has been measured at 77-380 K using the van der Pauw method. The experimental values were compared with the theoretical values obtained by an iteration technique. In the intrinsic region (T>250 K), the theoretical values were found to agree with the experimental values if the acoustic deformation potential constant, E
1 was chosen to be 14 eV.
Observation of Fluoresence Spectra near the Tip of Needle Electrode in Liquid Methane under Divergent Fields
Authors: Kouzu Yuji , Kitani Isamu , Arii Kiyomitsu
Published: November 2005

We investigated the dissociation phenomena of liquid methane(LCH4), the simplest hydrocarbon-liquid type structure, at the tip of a needle electrode, mainly by means of an observation of the fluorescence spectra. The CH peak observed in LCH4 shifted to a longer wavelength than in gaseous CH4. Near the tip of the point electrode, no bubble was found. These results indicate that molecular fragments in the liquid phase emit photons, the fluoresence being in LCH4.
A Trial Fabrication of Circular Buried Heterostructure (CBH) GaAlAs/GaAs Surface Emitting Laser by Using Selective Meltback Method
Authors: Kinoshita Susumu , Odagawa Tetsufumi , Iga Kenichi
Published: November 2005

For the purpose of introducing a current-confining structure to a GaAlAs/GaAs surface emitting (SE) laser, a circular buried heterostructure (CBH) was proposed. A selective meltback method was employed in order to avoid the oxidization of GaAlAs. The threshold current of an SE laser was 300 mA under a pulsed condition at room temperature. The nominal threshold current density was 20 kA/cm2/µm.
Local Control of Plasmas by Focused RF-Fields
Authors: Ohnuma Toshiro
Published: November 2005

With the use of resonance cone fileds from a ring source, focused RF-fields were experimentally produced in a magnetized plasma. In the focal region, a strong local change in the plasma, that is, a strong increase in the electron temperature, was observed.
Effects of Translational Temperature Relaxation on Intensities of Supersonic Molecular Beams
Authors: Teshima Koji
Published: November 2005

The effects of a translational temperature relaxation on the intensities of molecular beams sampled under an ideal skimming condition are evaluated against source conditions and diameter ratios of the orifice and the skimmer entrance. The beam intensity is affected more due to the existence of the skimmer when a gas-kinetic relaxation model with a realistic interaction potential is used than when isentropic and sudden-freezing flows are assumed.
Dependency of Boron Doping Efficiency on Hydrogen Flow Rate in Hydro-Fluorinated Amorphous Silicon
Authors: Ihara Hisanori , Uesugi Takashi , Matsumura Hideki
Published: November 2005

Boron-doping properties of hydro-fluorinated amorphous silicon (a-Si:F:H) films, produced by a glow-discharge decomposition of intermediate species SiF2 and H2 gas mixture, were studied for various deposition conditions. It was found that the boron-doping efficiency in a-Si:F:H depends on the hydrogen flow rate during deposition, that is, on the H content or H-related structure in the film. Thus, it was indicated that a deposition method in which the hydrogen flow rate can be widely adjusted is desirable for highly efficient doping of boron in hydro-fluorinated amorphous semiconductors.
Electronic Properties of the Interface between Si and TiO2 Deposited at Very Low Temperatures
Authors: Fuyuki Takashi , Matsunami Hiroyuki
Published: November 2005

Uniform TiO2 thin films with a large ε
r (up to 86) were prepared at low temperatures (200-400°C) by CVD. The films deposited at 200°C were amorphous and those at high temperatures were polycrystalline structures of anatase. The electronic properties of a TiO2/Si interface were analyzed in detail using metal-insulator-semiconductor structures. The minimum interface state density in the bandgap was as low as 2×1011 cm-2 eV-1, showing the usefulness of the TiO2 films for the gate insulators of MIS diodes. An anomalous behavior of photo-induced current observed for the first time is also presented.
Structural Changes of Amorphous Ge1-xSnx Alloy Films by Annealing
Authors: Fukumoto Hirofumi , Myoren Hiroaki , Nakashita Toshio , Imura Takeshi , Osaka Yukio
Published: November 2005

Microcrystalline (µc-) grains of Ge1-y
Sn
y
(0.1<y<0.4) were precipitated by thermal treatments of amorphous films of a Ge1-x
Sn
x
(x<0.4) alloy deposited by co-sputtering. At higher temperatures grains of β-Sn came out, co-existing with those of µc-Ge1-y
Sn
y
. Mössbauer spectroscopy was used to characterize states of Sn in a Ge-Sn alloy film. Optical properties, such as the real part ε
1 of the complex dielectric constant for Ge0.65Sn0.35, also changed as the structure change, especially at a photon energy of 1.6∼1.8 eV, where ε
1 took a maximum. It was suggested that an amorphous Ge-Sn alloy might be a good material for archival-type optical storage.
Superconductive Controlled Weak-Links
Authors: Okabe Yoichi , Anprung Prasan , Fukuoka Katsuhito
Published: November 2005

Three-terminal superconductive devices with a crossed-line structure (superconductor and a normal conductor), named superconductive controlled weak-links (SCW), have been fabricated. The devices operate in four main regions and their critical currents were continuously controlled by the gate current down to the normal state. Furthermore, the current gain between the critical current of a device and a gate current as high as 95 has been obtained. Some of the fabricated devices manifest ac Josephson effects when irradiated with microwaves of a suitable power over a temperature range from slightly above 4.2 K.
Picosecond Laser Induced Rapid Crystallization in Amorphous Silicon
Authors: Kanemitsu Yoshihiko , Kuroda Hiroto , Nakada Ichiroh
Published: November 2005

Rapid crystallization processes in ion-implanted amorphous silicon were investigated by using picosecond laser pulses. Two different thresholds for crystallization were observed. One of crystallization thresholds was found to be clearly below the amorphization threshold. The other crystallization threshold was well above the amorphization threshold. Additionally, well-marked boundaries were observed at the irradiation of two pulses separated by nanosecond time delays. At a small spot size, the irradiated sample surface became undulating. It is pointed out that inhomogeneous melting as well as shock stress are important in the rapid crystallization process at energy densities just below the amorphization threshold.
MOCVD Growth of GaAs1-xPx (x=0-1) and Fabrication of GaAs0.6P0.4 LED on Si Substrate
Authors: Takeyasu Masanari , Sakai Shiro , Soga Tetsuo , Umeno Masayoshi
Published: November 2005

Single-crystalline GaAs1-x
P
x
(x=0-1) layers were grown on (100)2° off Si substrates by metal-organic chemical vapor deposition using GaP and superlattices as intermediate layers. A very smooth mirror-like surface was obtained in the range x=0-0.4. Light-emitting diodes emitting at 655 nm have been fabricated in the GaAs0.6P0.4 layer on a Si substrate.
Optical Band-Pass Filter Using Accidental Isotropy and Optical Activity of AgGaSe2 (II)
Authors: Yamamoto Tatsuyuki , Takehara Hiroyasu , Horinaka Hiromichi , Miyauchi Takeshi
Published: November 2005

This paper is a sequel to a previous paper (Jpn. J. Appl. Phys. 24 (1985) 463), which dealt with an optical band-pass filter which utilized the accidental degeneracy of the refractive indices and the optical activity of an AgGaSe2 crystal. It theoretically expressed a method for controlling the band width and, further, predicted that the central wavelength of the filter could be changed by using a mixed alloy of AgGaS2 and AgGaSe2.
In this research, these two problems were confirmed experimentally.
Effect of Surface Roughness and Crystal Shape on Performance of Bismuth Germanate Scintillators
Authors: Ishibashi Hiroyuki , Akiyama Seikichi , Ishii Mitsuru
Published: November 2005

To improve the scintillation output of bismuth germanate scintillators, the influence of surface roughness and crystal shape has been experimentally studied. We found that an optimum scintillation output is obtained for an appropriate aspect ratio of the scintillator, i.e., its length “h” to width “a” (h/a), depending on their surface roughness. A high scintillation light output can be obtained for polished scintillator surfaces when h/a>6, but for rough surfaces when h/a<6. In addition, when scintillator surfaces are provided with a reflective coating, the light output is markedly improved. The dependence of the light output on the surface roughness and crystal shape is discussed in terms of the transmission loss inside the scintillator and the reflection loss at the surface.
Influence of Base Materials on the Characteristics of Zinc Electroplates and the Whisker Formations
Authors: Takemura Taketoshi , Kobayashi Masahiro , Okutani Masayuki
Published: November 2005

The influence of base materials on the characteristics of zinc electroplates and whisker formations was investigated for zinc with a (0002) preferred orientation and silicon steel with (110) oriented grains. As the electroplated thickness increased, the (112̄0) texture increased, while the number of whiskers and nodules formed on these electroplates increased at first steeply and then decreased slowly.
Optical Detection Voltage with Glow Discharge in a DC Magnetic Field
Authors: Ueda Hiroyuki , Miyawaki Sawami , Iida Yukio , Morita Masanobu
Published: November 2005

A theoretical analysis of the optical detection voltage with a glow discharge in a DC magnetic field (PIG type) is described. The detection voltage was calculated using the Langevin equation, and a theoretical curve of the detection voltage against the power density of light was obtained and compared with the experimental results.
Drift Characteristic of Capacitive Transducer Using Glued Electrodes
Authors: Kuroda Kazuaki , Nakayama Kan
Published: November 2005

The drift characteristics in glued electrodes of a capacitive transducer for small displacements were measured for two kinds of adhesives. The factors determining drift in the nanometer range are discussed.
Photoelectric Properties of Oxygen-Doped a-Si:H Prepared by rf Sputtering
Authors: Jiranapakul Koarakot , Shirakawa Kazuhiro , Shirafuji Junji
Published: November 2005

It was observed that the incorporation of a small amount of oxygen into sputtered a-Si:H films considerably enhances the photoconductivity at room temperature in comparison with that in undoped films. The mechanism of the enhancement was investigated in terms of the dangling-bond density, electron mobility and Fermi-level location. The electron lifetime was found to be roughly inversely proportional to the Si dangling-bond density. Time-of-flight experiments revealed that the electron mobility at room temperature in slightly oxygen-doped films is higher by about one order of magnitude than that in undoped films. The greatest part of the photoconductivity enhancement could be understood on the basis of an increase in the electron mobility and a reduction in the dangling-bond density.
PL Property of ZnTe Grown by Chemical Transport and Its Growth Method Dependency
Authors: Nishio Mitsuhiro , Ogawa Hiroshi , Nishinaga Tatau , Washiyama Masako
Published: November 2005

Photoluminescence (PL) spectra have been measured at liquid-He temperature for epi-layers in a ZnTe-HCl closed-tube system as well as in ZnTe-H2-HCl and ZnTe-H2 open-tube systems. The epi-layers in the ZnTe-HCl system exhibited spectra characterized by a sharp neutral acceptor bound-exciton line in the near-band edge. The intensity of this line increased with decreasing substrate temperature or growth rate. On the other hand, the spectrum in an epi-layer grown in a ZnTe-H2-HCl system is characterized by deep-level emission. A growth model in which the growth is controlled by diffusion through the boundary layer as well as by a surface kinetics process is tentatively proposed and the relationship between crystal quality and the growth condition is discussed. The effect of HCl upon the PL spectra is also discussed by comparing growth with and without HCl.
Orientation Dependence of Flaking of Ion Irradiated Aluminum Single Crystals
Authors: Ono Kotaro , Kino Takao , Kamada Kohji , Osono Hiroto
Published: November 2005

Surface erosion on mono- and poly-crystalline aluminum, irradiated with 300-500 keV He+ or Ne+ ions at room temperature along the axial or off-axial directions, has been examined by SEM and TEM. The critical fluence at which flaking appears on the surface increased according to the order of the poly-crystalline sample, mono-crystals with surface normals of [111], [100] and [110]. On the contrary, flaking over multiple layers first appeared on a (110) surface. Results of skin-thickness measurements and microstructure observations suggest that flaking is basically caused by the coalescence of small bubbles which are created in a layer close to the projected ion range. The orientation dependence of the flaking was interpreted in terms of a difference in the depth profile of the bubble distribution associated with channelled ions. Some discussions are made concerning blisterling.
Clustering Poisson Process and 1/f Noise
Authors: Grüneis Ferdinand , Musha Toshimitsu
Published: November 2005

A physical interpretation has been given to the clustering Poisson process which results in a 1/f spectrum; this model is compared with a model in which the 1/f spectrum is derived from a superposition of the Lorentzian spectra. For a point process, an expression has also been derived for the higher-frequency limit to 1/f fluctuations burried in shot noise.
A New Analytical Method of Amorphous Silicon Solar Cells
Authors: Takahama Tsuyoshi , Isomura Masao , Tsuda Shinya , Tarui Hisaki , Hishikawa Yoshihiro , Nakamura Noboru , Nakashima Yukio , Matsuoka Tsugufumi , Nishiwaki Hidenori , Ohnishi Michitoshi , Nakano Shoichi , Kuwano Yukinori
Published: November 2005

A new analytical method for amorphous silicon solar cells, called DICE (dynamic inner collection efficiency), has been developed. The depth profile of the photovoltaic characteristics of solar cells can be obtained by using the DICE method under any operating condition in a non-destructive manner for the first time. The DICE value is defined as the probability that an electron-hole pair generated at a certain depth in the generated region of an a-Si solar cell becomes an output current. In this paper the theory and the calculation method of DICE are described, and the results of applications to practical solar cells are reported. By using the DICE method it was found that carrier recombination at the p/i interface affects the open-circuit voltage.
Time-Resolved Studies on Recombination Luminescence of Donor-Acceptor Pairs in ZnSe
Authors: Ohishi Masakazu
Published: November 2005

Time-resolved studies of luminescence due to the recombination of donor-acceptor pairs in ZnSe are reported. Several sharp luminescence lines were observed under excitation below the band-gap energy, resulting in a determination of the binding energy of the Al donor to be 26.7 meV and that of Na acceptor to be 114 meV. It was also confirmed from analyses of the decay characteristics of the donor-acceptor pair luminescence that the hydrogenic model for energy levels as well as for the Bohr radius holds true for the Al donor. However, for the Na acceptor the Bohr radius which satisfied the experimental decay kinetics should be less than half of the value calculated using the effective-mass approximation.
Electromagnetic Acceleration of Macroparticles to Hypervelocities with Self-Crowbarring Ablation Mass Driver
Authors: Ikuta Kazunari , Rathbun Kenneth
Published: November 2005

The electromagnetic acceleration of macroparticles to hypervelocities in an axisymmetric geometry was reconsidered in order to employ high-energy-density capacitors (HEDC) as an energy source. This new version of an accelerator has self-crowbarring electrodes arranged periodically in the electrode array; these electrodes can avoid a voltage reversal of HEDC since the allowable voltage reversal for HEDC is significantly low.
Stabilization of a Dye-Sensitized Photocathode by Deposition of Platinum
Authors: Tannakone K. , Fernando C. A. N. , Kariapper M. S. , Dewasurendra M.
Published: November 2005

The photodegradation of the dye in a sensitized p-CuCNS photocathode was found to be suppressed by a deposition of trace quantities of platinum. The mechanism involved is discussed.
High Dielectric Constant of a Mixture of N-Alkyl Aliphatic Amides
Authors: Takagi Seishi
Published: November 2005

The dielectric constants of various mixtures of N-methylpropionamide (NMP) and N-ethylpropionamide (NEP) were measured. Mixtures in which the mole fraction of NMP was 0.80 easily became a supercooled liquid below -50°C and its dielectric constant showed a maximum value of 660 at -77°C.
Critical Radial Temperature Gradient Inducing Slip Dislocations in Silicon Epitaxy Using Dual Heating of the Two Surfaces of a Wafer
Authors: Akiyama Noboru , Inoue Yohsuke , Suzuki Takaya
Published: November 2005

Heating both wafer surfaces allowed us to efficiently control the radial temperature gradient, dT/dr, even for large wafers (150 mm diameter). With an epitaxial-growth apparatus using dual heating of the two surfaces of a wafer, the relation between inducing slip dislocations and the values of dT/dr were experimentally examined. It was found that it was necessary to keep the maximum temperature gradient lower than between 6 and 11°C/cm in order to accomplish slip-free epitaxy in the temperature ranges of 1100°C to 1250°C and at 930°C, respectively. The maximum shear stresses were calculated for the temperature distributions of each wafer by a finite-element computer model. It was concluded that the critical shear stress (inducing slip dislocations) was between 6×106 and 9×106 N/m2 in the temperature range between 1100 and 1250°C and at 930°C, respectively.
Work Function and Dipole Barrier of Sputter-Cleaned Fe-Ni Alloy Surfaces
Authors: Maeda Takao , Saito Shigeru
Published: November 2005

The contact potential differences of Fe-Ni alloy surfaces were measured with respect to Au by means of the Kelvin method. The work function of the alloys were obtained from the measured values. The variation of the work function with alloy composition could be explained from the contribution of the surface dipole potential, of which the variation was qualitatively estimated from changes in a tentative Wigner-Seitz cell radius of the alloys estimated from the mean atomic volume and in the electron density at the cell boundary.
Simulation Studies of a Composition Analysis by Thickness-Fringe (CAT) in an Electron Microscope Image of GaAs/AlxGa1-xAs Superstructure
Authors: Kakibayashi Hiroshi , Nagata Fumio
Published: November 2005

The intensity distribution of thickness fringes, observed at the edge of a cleaved chip of GaAs/Al
x
Ga1-x
As superstructure using a transmission electron microscope, was computer-simulated by means of the dynamical theory of electron diffraction. It was theoretically verified that the distance of a thickness fringe from the edge of a chip systematically changes, depending on the Al composition (experimentally found by the present authors (H. Kakibayashi and F. Nagata: Jpn. J. Appl. Phys. 24 (1985) L905)). The precise composition profile in the heterointerface and the most suitable observation condition for a composition analysis were studied using the simulation technique.
Inhomogeneous Concentration Distribution in Obliquely Evaporated Fe-Cu Films
Authors: Keitoku Susumu , Kamimori Tatsuo , Goto Mitita
Published: November 2005

A distribution of atoms or local concentration in Fe
x
Cu1-x
films prepared by an oblique incident beam is discussed based on the results of the magnetization, Mössbauer effect, X-ray diffraction and simulation of a film-formation process. From these experiments, it was concluded that an inhomogeneous concentration distribution takes place in a column which is formed by oblique incidence. In each column three kinds of regions (Fe, Fe-Cu and Cu) are found, depending on the iron contents (x) and the incidence angles (θ). When θ is small, only an Fe-Cu region appears; this is an Fe-rich (bcc) or Cu-rich (fcc) alloy corresponding to large or small x, respectively. When θ is large, Fe and Cu regions appear instead of Fe-Cu regions; also, x affects the volume ratio of the Fe to Cu regions.
Band Gap Energy and Stress of GaAs Grown on Si by MOCVD
Authors: Sakai Shiro , Soga Tetsuo , Umeno Masayoshi
Published: November 2005

The band gap gap energy and stress of GaAs grown on Si using (GaP/GaAsP) and (GaAsP/GaAs) superlattice intermediate layers were measured by electro-reflectance and wafer bending. It was found that high-density dislocations or defects which can relax stress exist during the early stages of the growth and decrease with the growth sequence; the growth temperatures have significant effects on crystal perfection.
Decay Rate Plot of Stored Beam Current and Touschek Limit of Current-Lifetime Product
Authors: Tomimasu Takio , Yamazaki Tetsuo , Mikado Tomohisa , Sugiyama Suguru , Chiwaki Mitsukuni , Nakamura Takeshi , Noguchi Tsutomu
Published: November 2005

It is demonstrated that the decay rate of the stored beam current I is a good means for indicating the gas-pressure conditions of a storage ring and the stored beam loss due to the Touschek effect. A new analytical method for evaluating the Touschek lifetime of the stored electron beam is also presented. The observed Touschek limit of the current-lifetime product I
0τ
T
is 5 Ah at 500 MeV for TERAS. This value is fifty times as large as the theoretical value. I
0τ
T
is proportional to the fourth power of the electron energy E and becomes of the order 0.12 Ah at 205 MeV. A computer-made decay-rate plot against I is very useful for indicating the decay modes and the 1/e lifetime of the stored beam current.
Chemical Vapor Deposition of a-Si:H Films Utilizing a Microwave Excited Ar Plasma Stream
Authors: Watanabe Takeshi , Azuma Kazufumi , Nakatani Mitsuo , Suzuki Kazuo , Sonobe Tadashi , Shimada Toshikazu
Published: November 2005

A Microwave-excited Ar-plasma stream produced at low gas pressures (10-4 to 10-2 Torr) was applied to a preparation of hydrogenated amorphous silicon films made from SiH4. The electric and optical properties of the films were investigated as functions of the deposition conditions. The film properties greatly depended upon the substrate temperature and the deposition pressure and slightly upon the microwave power. The conductivity of the films prepared at 200°C and at pressures ranging between 0.6 and 0.8 mTorr were about 5×10-10 S·cm-1 in the dark and 4×10-4 S·cm-1 under AM 1.5 illumination. The films prepared at the lower pressures were porous and contain a large amount of gases; the films prepared at higher pressures were deteriorated in the same way as those prepared by an RF glow discharge from Ar-diluted SiH4.
Lattice Strain of Selectively Grown Silicon Epitaxial Layer
Authors: Miyamoto Nobuo , Kanai Akira , Kato Hiroshi
Published: November 2005

This paper reports on the selective growth of silicon epitaxial layers on a (100) silicon substrate having a delineated SiO2 film in an SiH2Cl2-HCl-H2 gas system under atmospheric pressure. The lattice strain of the epitaxial layers was measured using the half angle of the rocking curves and the diffraction contrast of the topographs; these were obtained using the X-ray double-crystal method at room temperature. The elastic strain of the lattice was observed in a selective epitaxial layer having an SiO2 masking film. A weak diffraction contrast was found to remain even after the masking film was removed. This contrast was found to disappear when the direction of the side-wall of the grown layer coincided with that of the incident X-ray projection. The lattice strain was considered to be caused by a difference in the thermal-expansion coefficients of the silicon and the SiO2 film.
Observation of Transient Behavior of GaAs MBE Growth by RHEED Oscillation
Authors: Sugiura Hideo , Kawashima Minoru , Horikoshi Yoshiji
Published: November 2005

This paper discusses the transient behavior of the GaAs single monolayer growth observed using RHEED specular beam intensity oscillation. The time required for the 1st monolayer growth just after the Ga cell shutter opening depends strongly on the growth surface location. At a fixed location, the first monolayer growth time increases with the substrate temperature and decreases as the As flux intensity is increased. The first monolayer growth time varies according to the electron beam incident directions. In contrast, the growth rate of each succeeding layer does not depend on these parameters, and is simply determined by the impinging rate of Ga atoms. A similar phenomenon was observed in AlAs growth. The anomalous characteristics of the first monolayer growth were interpreted while taking into consideration the atomic-step density limited growth process.
Dielectric, Piezoelectric and Optical Properties of Hot-Pressed Sr(La1/2Nb1/2)O3-PbZrO3-PbTiO3 Ceramics
Authors: Yokosuka Masaru
Published: November 2005

Investigations were made regarding the hot-pressed ceramics of a solid solution in a ternary system Sr(La1/2Nb1/2)O3-PbZrO3-PbTiO3. Optical and electrooptical properties were studied for various compositions in the vicinity of the morphotropic phase boundary between the tetragonal and the rhombohedral phases. Dielectric and piezoelectric measurements together with an X-ray analysis were also carried out over a wide range of compositions; also, the phase diagram was determined.
The overall characteristics were found to resemble those of PLZT.
InP PN Junction Waveguide Made by Mg-Ion Implantation
Authors: Ōigawa Kinya , Uekusa Shin-ichiro , Sugiyama Yoshinobu , Tacano Munecazu
Published: November 2005

Fabrication processes to make an excellent p
+
n-junction on bulk n-InP by 24Mg-ion implantation are described. The leakage-current density through a junction was less than 10-7 A/cm2 with a rectification ratio larger than 106 at a bias voltage of - 1 V and a junction breakdown voltage below - 60 V without any guardring structure. A 2.0-mm long junction waveguide was used to control the long-wavelength (λ=1.135 µm) light with an extinction of 8.6 dB at 10 V.
Optical Waveguide of Nd-Doped Garnet Thin Film RF-Sputtered on Y3Al5O12 Substrate
Authors: Yamaga Mitsuo , Yusa Koumei , Miyazaki Yasumitsu
Published: November 2005

Nd-doped garnet thin-film waveguides which can be used as optical amplifiers were prepared on YAG substrates by rf sputtering. The composition, crystal property and optical propagation loss of the films were found to be quite sensitive to the substrate temperature (T
s). The film prepared at T
s=650°C was amorphous with a stoichiometric composition Y3Ga5O12, while that prepared at T
s=790°C showed a single-crystalline phase and the composition was represented by Y4Ga4O12 with the garnet structure. The propagation loss of light at λ=0.633 µm abruptly decreased from about 30 dB/cm to 5 dB/cm as T
s exceeded 700°C. Recrystallized thin films with the stoichiometric composition Y3Ga5O12 were prepared by thermal treatment, and the loss was reduced to about 2 dB/cm.
Structure of Films Prepared by Glow Discharge Decomposition of Hexafluorodisilane
Authors: Kumeda Minoru , Takahashi Yukio , Shimizu Tatsuo
Published: November 2005

The structure of films prepared by the glow discharge decomposition of hexafluorodisilane (Si2F6) gas was investigated. Such films are considered to be predominantly an admixture of a (SiF2)
n
chain and a SiO2 cluster with a small interface region of hydrogenated amorphous Si.
An Extended X-Ray-Absorption Fine-Structure Study of Bond Lengths in GaAs1-xPx
Authors: Sasaki Toru , Onda Tomohiro , Ito Ryoichi , Ogasawara Nagaatsu
Published: November 2005

Extended X-ray-absorption fine-structure measurements were performed on GaAs1-x
P
x
, a typical III-V-V type semiconductor alloy, with the composition x as a parameter. The results reveal that the Ga-As and Ga-P nearest-neighbor bond lengths differ, showing a tendency to retain their respective bond lengths in the binary compounds. This feature is similar to that found earlier in Ga1-x
In
x
As, a III-III-V type alloy.
Maximum Entropy Spectral Analysis of Time-Series Data from Combustion MHD Plasma. II. The Effect of An Externally-Applied Magnetic Field on the Plasma Turbulent Flow
Authors: Seidou Tadashi , Aoki Yoshiaki , Ohtomo Norio
Published: November 2005

The Maximum Entropy Method (MEM), as a high-resolution estimator, was applied to analyse of time-series data from a combustion MHD plasma with an externally-applied magnetic field. Deviation of the k-dependent power spectral densities from Kolmogoroff's k
-5/3 -law was found in the inertial subrange (k: wave number): a k
-3 -dependent power spectral density due to the effect of the strong magnetic field on the plasma turbulent flow was observed in the higher part of the range.
Rate of Production of Water Vapour in Low-Power, High-Repetition-Rate Discharge Cleaning
Authors: Matsuzaki Yoshimi , Suzuki Norio , Hirayama Toshio
Published: November 2005

The effects of low-power, high-repetition-rate discharge cleaning in a tokamak have been investigated by measuring the water vapour pressure at different values of the filling pressure, plasma current and repetition rate. As the filling pressure and repetition rate increase, the water vapour pressure also increases, while the optimum value of the plasma current for the production of H2O in the JFT-2 tokamak is 5 ∼ 10 kA. The time variation of H2O was measured and it was found to decrease as the t
-0.9 law. These results are explained by a water particle balance equation derived from a simplified model and by the plasma density and temperature measured by a double probe in the scrape-off layer.