bluuebunny/crossref_metadata_2025 huggingface dataset:
Room Temperature Operation of Al0.17Ga0.83Sb/GaSb Multi-Quantum Well Lasers Grown by Molecular Beam Epitaxy
Authors: Ohmori Yutaka , Tarucha Seigo , Horikoshi Yoshiji , Okamoto Hiroshi
Published: November 2005

A room-temperature lasing-operation by current injection to Al0.17Ga0.83Sb/GaSb multi-quantum well (MQW) lasers grown by molecular beam epitaxy (MBE) is demonstrated. A pulsed threshold current density of 8.9 kA/cm2 was obtained for the diode whose active layer consists of 16 periods of 91 Å thick GaSb well layers separated by 31 Å thick Al0.17Ga0.83Sb barrier layers. The observed lasing energy (0.753 eV) is 27 meV higher than the energy gap of GaSb, indicating the quantum size effect.
Theoretical Analysis of Rb and Cs D2 Lines in Doppler-Free Spectroscopic Techniques with Optical Pumping
Authors: Nakayama Shigeru
Published: November 2005

The relative intensities of the Doppler-free signals of the 85Rb and Cs D2 lines in saturation spectroscopy, velocity-selective optical pumping (VSOP) spectroscopy, and polarization spectroscopy were calculated theoretically, taking into accont the optical pumping process in the Zeeman sublevels and arbitrary polarization combinations for pump and probe beams. Both circular and linear optical anisotropy induced by the pump beam were considered in the theoretical calculation. The magnitude and sign of the Doppler-free resonances in each spectroscopic method were quite different owing to the polarizations of the pump and probe beams. The theoretical results obtained from a single-cycle optical pumping in a four-level approximation were in good agreement with recent experimental reports.
Electron Microscopy and Diffraction Studies of the Structure of Amorphous WO3 Film
Authors: Kaito Chihiro , Shimizu Tsukasa , Nakata Yukinori , Saito Yoshio
Published: November 2005

High-resolution electron-microscopic observation and analysis of the amorphous halos in electron diffraction have been carried out on WO3 film prepared by vacuum deposition. Crossed fringes forming a region about 1 nm in size are frequently seen in the micrographs, and each of their spacings corresponds to that of the lattice spacing of the WO3 crystal. On tilting the film, the lattice fringes in some regions disappeared and new fringes appeared at different positions. This shows that the micro-crystallites are distributed at random in the film. The experimental electron diffraction intensity is explained by a micro-crystal model in which microcrystallites are distributed at random with sizes of 0.8, 1.0 and 1.2 nm at ratios of 23, 54 and 23%, respectively.
Raman Spectrum of Selenium Dissolved in an Aqueous Solution of Sodium Sulfide
Authors: Nagata Kiyofumi , Ishikawa Takatoshi , Miyamoto Yasuhiko
Published: November 2005

The Raman spectrum of selenium dissolved in an aqueous solution of sodium sulfide was measured using an YAG laser and a multiple-reflection cell, and an intense broad band was observed at 264 cm-1. This frequency is higher than those of the corresponding symmetric bond-stretclaing modes in any solid form of selenium. This is explained by considering the decrease of the interference between inter- and intramolecular bondings in the solution.
Investigation of TLD Phosphors by Optical Excitation –Luminescence of Eu2+Centers in MgSO4, CaSO4, SrSO4, BaSO4–
Authors: Yamashita Nobuhiko , Yamamoto Isao , Ninagawa Kiyotaka , Wada Tomonori , Yamashita Yoshihiko , Nakao Yasuhiro
Published: November 2005

The photoluminescence (PL) and excitation spectra of various thermoluminescence dosimetry (TLD) phosphors were measured at temperatures of 6, 17, 80 and 300 K. Their PL spectra at 300 K consist of a single band in the vicinity of 380 nm. The emission bands and their excitation bands are ascribed to the electronic 4f6·5d↔4f7transitions in the Eu2+ions. In the PL spectra of MgSO4:Eu2+, SrSO4:Eu2+and BaSO4:Eu2+, the emission lines due to the electronic 4f7→4f7transition in the Eu2+ion were also observed near 360 nm, in addition to the broad band. No line emission due to the Eu3+center was observed in any of the phosphors prepared in the present work. In CaSO4:Eu2+cooled to low temperatures, phonon structures are observed on the emission band and the low-energy excitation band. The TL emission spectra of BaSO4:Eu2+at various temperatures were also measured.
Kinetic Studies of the Electron-Beam-Pumped ArF Laser Using an Ne/Ar/F2 Mixture
Authors: Suda Akira , Obara Minoru , Fujioka Tomoo
Published: November 2005

By experimentally optimizing the operational parameters for the electron-beam-excited ArF laser, an intrinsic efficiency of 4.4% was obtained for a 4 atm Ne/Ar/F2 mixture pumped by a 50 ns pulse at an excitation rate of 1.4 MW/cm3. Under these conditions, the measured net gain was 5.5%cm-1, which agrees well with the value of 6.0%cm-1 estimated from a modified version of Rigrod's theory. Assuming an infinite V-T relaxation rate for ArF*(B), the small-signal gain and absorption were estimated as 6.4%cm-1 and 0.35%cm-1, respectively. With an Ar/F2 mixture, it was difficult to obtain efficient ArF lasing, while with a Ne/Ar/F2 mixture, efficient lasing was readily obtainable even at low excitation rates. This is attributed mainly to the fact that the ArF* deactivation rate to form Ar2F* trimer if faster with Ar gas than with Ne gas.
Electric Discharge and Fractals
Authors: Fujimori Seiichi
Published: November 2005

Electric discharge simulations, especially those of streamers, are usually based on the Liouville equation. However, there have been extremely few studies of the morphology of electric discharges. Morphological research methods have the advantage of allowing common characteristics over different fields, e.g., biology, physical geography etc., to be extracted. In this work, a fractal dimension analysis of streamers simulated by computer with random numbers, the dimension being on feature of the morphology, was performed to obtain the fractal dimension of streamer-modeled figures. The fractal dimension is about 1.23 to 1.54 for figures having many streamers (300-streamer channels) and fluctuates for streamers having slight branching. The overall geometrical changes of the patterns formed by the streamer development cause the fractal dimension to change rapidly.
Phase Relations in the AuCu1-yAgy and Au(Cu1-yAgy)3 Ternary Systems
Authors: Kogachi Mineo , Nakahigashi Kiyotaka
Published: November 2005

The phase relations in the ternary systems AuCu1-y
Ag
y
and Au(Cu1-y
Ag
y
)3 have been studied by X-ray diffraction and differential thermal analysis. In AuCu1-y
Ag
y
, the phase diagram obtained showed considerably complex features at low temperatures between 683 and 573 K, with eight different regions: three single-phase regions; α(disorder A1), β(order L10) and γ(order L10–S); four two-phase regions, α1(Cu-rich A1)+ α2(Ag-rich A1), β+α2, γ+α1 and γ+α2; and one three-phase region, γ+α1+α2. The phase boundaries of three pairs of regions, α1+α2 and α, β+α2 and α, and γ+α2 and α, were determined by measuring the lattice parameters. In Au(Cu1-y
Ag
y
)3, two single-phase regions, α and α' (order L12); and two two-phase regions, α1+α2 and α'+α2, were found, and the corresponding phase boundaries were determined.
Preferential In-Water Oxidation around Defects in Undoped LEC Semi-Insulating GaAs Wafers
Authors: Yasuami Shigeru , Fukuta Katsuyoshi , Nakanisi Takatosi
Published: November 2005

Boiling an undoped LEC semi-insulating GaAs wafer in deionized water forms an oxide film on the wafer which gives a visual representation of the defects in the wafer. This preferential oxidation of GaAs was found to be promoted by photons. These findings suggest that the density of photogenerated holes, which play the leading role in oxidation, should be high around defects, because defects, such as dislocations and lineage, can absorb hole traps. The oxide film is thus thick in the vicinity of a defect and thinner away from it. The defect pattern can be extinguished by carrier doping prior to boiling.
Three States of Substitutional Gold in Silicon
Authors: Morooka Masami , Tomokage Hajime , Kitagawa Hajime , Yoshida Masayuki
Published: November 2005

Supersaturated substitutional gold in silicon was annealed by two different methods. In one method, termed “ordinary annealing”, the specimen was pulled out of the furnace after the indiffusion of gold and cooled rapidly to room temperature, and then heat treated again for annealing. In the other method, termed “continuous annealing”, the specimen was kept in the furnace after the indiffusion, the temperature of the furnace was reset at the annealing temperature, and then the annealing was carried out.
It was found that whether the specimen temperature was allowed to drop below 850°C or not after the indiffusion was an important factor in the annealing. It was deduced that substitutional gold has three states: high-temperature substitutional gold, low-temperature substitutional gold and agglomerates of substitutional gold.
Saturation Behavior of Balmer-Line Fluorescences in a Hydrogen Plasma
Authors: Arata Yoshiaki , Miyake Shoji , Matsuoka Hidesato
Published: November 2005

Widely broadened H
α and H
β line fluorescences attributed to saturation broadening were obtained with a high accuracy in the saturation spectroscopy of a hydrogen plasma with electron density ranging from 1014 to 1015 cm-3. Observation of this broadening showed that it was possible to extract the contribution of the Stark (homogeneous) effect in a line emission originally governed by the Doppler profile, which also enabled the electron density to be evaluated without measuring the Stark profile.
Defect-Trapping by Sn Atoms Implanted in Aluminum
Authors: Yagi Eiichi , Koyama Akio , Nakamura Shiho , Sakairi Hideo , Hasiguti Ryukiti R.
Published: November 2005

The lattice locations of Sn atoms implanted in Al crystals were investigated by the channeling method. Sn atoms were implanted at room temperature and 150 kV at three different doses; 1×1014/cm2, 4×1014/cm2 and 1×1015/cm2. For all three doses, most of the Sn atoms were located at random (R) sites, i.e. in the precipitates. In the 1×1014/cm2 implantation, the remaining atoms were located at substitutional (S) sites and at slightly-displaced interstitial positions (I-sites). As the dose was increased to 4×1014/cm2, the occupancy of S- and I-sites decreased, while octahedral (O) and terahedaral (T) site occupancies were observed. In 1×1015/cm2 implantation, almost all the Sn atoms were at R-sites, with the remainder at S-sites. The I-site occupancy is interpreted as resulting from the trapping of a divacancy, and the O- and T-site occupancies from the trapping of more than two vacancies by an Sn atom.
The Study of Laser Produced Plasma Behaviour Using Streak Photography
Authors: Yilbaş Bekir Sami
Published: November 2005

The effect of energy, focus and material variation on flare frequency was examined in this work. A series of streak photographs were taken and analysed. Flare behaviour was shown to be widely different between different materials. Flare frequency was also shown to be independent of energy and focus with exceptions occuring at low power 10.1 J, and long focus F.100”. An unusual phenomenon was observed when copper was drilled at high energy and F.030.” Liquid globes ejected from the surface continued to flare. The effect of high energies on maximum particle velocity and drilling speed was also investigated.
Pressure Dependence of Carbon Film Coating by a Toroidal Methane Discharge
Authors: Kojima Hiroaki , Kako Hidenori , Terada Mamoru , Sugai Hideo , Okuda Takayoshi
Published: November 2005

A pure methane discharge under a toroidal magnetic field has been used to deposit thin carbon layers in situ onto the walls of a toroidal vessel, with a view to application to magnetic fusion devices. Hard carbon films with high electrical resistivity were formed on stainless steel, silicon, and NaCl substrates, in a wide range of methane pressure (10-4 ∼10-2 Torr). The film properties and structures were examined by infrared absorption, X-ray photoemission analysis, electron microscopy (TEM, TED, SUM), and so forth. The results show that the films predominantly consist of tetrahedrally bonded carbon (sp3 bonding). Both the hydrogen atom concentration in the films and the binding energy of the carbon atoms increase with increasing methane pressure. Also, the size of microcrystallites on a background consisting of an amorphous structure grows with increasing pressure.
In-Depth Profile Measurements of Cr-Related Luminescence Lines in GaAs
Authors: Fujiwara Yasufumi , Kojima Atsushi , Nishino Taneo , Hamakawa Yoshihiro
Published: November 2005

The in-depth profiles of two kinds of Cr-related deep luminescence centers, Cr-VAs and Cr-Te, in Cr-diffused GaAs crystals were determined from luminescence measurements at 4.2 K. The Cr-VAs center gave a steeper in-depth profile than the Cr-Te center. Analysis of these in-depth profiles of the Cr-VAs and Cr-Te centers has enabled us to estimate the diffusion coefficient of the Cr impurity and the arsenic vacancy VAs in GaAs crystals. The values obtained are 2 ∼4 ×10-11 cm2/s for Cr and 5 ∼8 ×10-12 cm2/s for VAs, comparable to previously-reported data. A steep decrease in the luminescence intensities of the Cr-related lines at the surface of the samples was also observed, suggesting the existence of residual strain.
DLTS Study on the Gradation of the Trap Concentration Profiles in n-CdTe Crystals
Authors: Tomitori Masahiko , Ishii Sugio , Kuriki Makoto , Hayakawa Sohachiro
Published: November 2005

DLTS measurements were carried out on three types of metal/n-CdTe junction: I. gold evaporated on an etched surface; II. gold evaporated on a cleaved surface; III. cadmium evaporated on a cleaved surface. Type I had a tellurium-rich layer and type III a cadmium-rich layer. The concentration of level E4(energy depthEC-ET=0.33 eV), one of the six electron traps detected in this experiment, decreased rapidly near the interface in type I at room temperature, but increased in type III. A relationship was found to exist between level E4and the non-stoichiometric layers. A model in which the gradation of this level's concentration was caused by the diffusion of defects, is proposed, and the diffusion coefficient is estimated to be about 10-17cm2·s-1from the concentration profiles of level E4.
Ion-Sheath Admittance in Cylindrical and Spherical Probes Near the Ion Plasma Frequency
Authors: Dengra A. , Colomer V. , Hernández M. A.
Published: November 2005

A theoretical model that allows the analytical calculation of the associated admittance of an ion-sheath of cylindrical and spherical probes near the ion plasma frequency is reported.
Theoretical results are compared with experimental data which are in agreement.
Simple Low-Cost Time-Interval Analyzer
Authors: Niiyama Wataru , Miyakawa Kenji
Published: November 2005

A detailed design of an apparatus for measuring the time intervals of statistical events is described. The apparatus can be constructed at very low cost and with high versatility by utilizing commonly-available integrated circuits. The apparatus was used to measure the beating rhythm of the cardiac cells of chicks in the very early developmental stages in an isolated system. The number of heartbeats per unit time was found to remain almost constant with time.
Correlation between the Intermolecular Potential in the Liquid Crystalline Phase and Viscosity
Authors: Muramatsu Hiromochi , Ohmi Shinya , Hara Kunihiko
Published: November 2005

The correlation between the intermolecular potential in the liquid crystalline phase and viscosity was studied using a quantum physical method.
It was found that there are strong correlations between the intermolecular potential and viscosity for both liquid crystals composed of one component and mixtures of multi-components of liquid crystals.
Epitaxial Growth of ZnS on Si by Metal Organic Chemical Vapor Deposition
Authors: Hirabayashi Katsuhiko , Kogure Osamu
Published: November 2005

This paper presents a new method of growing ZnS on Si substrates using metal organic chemical vapor deposition (MOCVD). The method includes the simple process of depositing a thin ZnS buffer layer on an Si(111) substrate prior to the ZnS growth. The ZnS buffer layer is prepared by electron-beam-evaporation at 220°C or MOCVD growth above 500°C, and the most suitable thickness of the layer is about 100 Å. The ZnS film prepared on the layer exhibits a reflection high-energy electron diffraction pattern which consists of elongated spots, indicating good surface morphology.
Probing the Crystallinity of Evaporated Silicon Films by Raman Scattering
Authors: Okada Tadashi , Iwaki Tetsuo , Kasahara Hajime , Yamamoto Keiichi
Published: November 2005

Changes in the Raman spectra of evaporated a-Si films resulting from thermal annealing are reported in terms of the peak frequency and linewidth of a TO-like mode and the volume fraction of crystallinity ρ, where ρ is determined from the integrated intensities of resolved modes corresponding to a crystalline component and an amorphous-like component. The peak frequency and the linewidth show abrupt changes as the annealing temperature T
a rises, while ρ varies slowly with T
a, indicating a continuous crystallization with a constant rate, from T
a <400^°C. Moreover, the activation energy of the crystallization can be calculated by fitting ρ to the Avrami formula and is found to be the activation energy for viscous flow (0.35 eV). The crystalline TO mode of the highly-crystallized film is also compared to the results of the theoretical calculation reported by Richter et al.
Magnetic Domain Structure of Fe3Al Alloy with Two-Phase Mixture Studied by Lorentz Microscopy
Authors: Watanabe Denjiro , Yamato Masayuki , Yuzurihara Hajime , Sekiguchi Takashi , Tanaka Toshiro , Takahashi Migaku , Wakiyama Tokuo
Published: November 2005

The Fe3Al single crystal alloys in the conditions of two-phase mixtures, α(disordered)+ B2 and α+D03, were examined by transmission electron microscopy, and the magnetic domain structures at room temperature were observed by the defocused mode of Lorentz microscopy. The magnetic contrast associated with the interface between the two phases coexisting in a submicron scale was observed, in addition to the domain wall contrast. The origin of the magnetic contrast is discussed in connection with the fluctuation of magnetization in the two-phase state.
Laser Cooling of an Atomic Beam by Spatial Doppler Tuning of a Resonance Transition
Authors: Umezu Jun , Shimizu Fujio
Published: November 2005

Cooling of an atomic beam by Doppler tuning is proposed. The atomic beam is decelerated by repeatedly crossing a resonant laser beam at a decreasing angle. An example of the experimental configuration to slow down a two-level atomic beam by a factor of 20 using two lasers is given.
Elimination of Complex Ions in Fluoride Glasses by NF3 Processing
Authors: Nakai Tetsuya , Mimura Yoshinori , Shinbori Osamu , Tokiwa Hideharu
Published: November 2005

The influence of complex ions (NH4
+, CO3
2-, NO3
-, SO4
2- and PO4
3-) in fluoride glasses on absorption loss is investigated. To remove these ions, reactive atmosphere processing with NF3 has been applied. NH4
+, CO3
2-, NO3
- and SO4
2- are effectively eliminated by the NF3 processing.
Behavior of Excess Te Atoms in Undoped p-type CdTe Annealed under Te Vapor Pressures
Authors: Yokota Katsuhiro , Yoshikawa Toshiharu , Katayama Saichi , Ishihara Shinji , Kimura Itsuro
Published: November 2005

The number of Te atoms and hole concentrations in undoped p-type CdTe quenched into water after annealing were investigated as functions of annealing temperature and Te2 vapor pressure. The number of Te atoms diffused from the annealing atmosphere into CdTe increased with increasing annealing temperature and Te2 vapor pressure, but decreased with additional increasing Cd vapor pressure. Te precipitates were observed by a scanning electron microscope in CdTe with diffused Te atoms more than approximately 1×1019 cm-3. The number of Te precipitates was increased with increasing Te vapor pressure, but was decreased by adding Cd vapor pressure. It was found that the precipitates resulted in a decrease in the concentration of the holes in p-type CdTe.
Electroluminescence of Devices with Thin-Film CaS:Ce3+, Cl- as the Active Luminescent Layer
Authors: Ogawa Masataka , Shimouma Takashi , Nakada Satoshi , Yoshioka Taisuke
Published: November 2005

Thin-film CaS:Ce3+, Cl- has been successfully employed for the first time as the active layer of an a.c. thin-film electroluminescent device. In order to compare the performance of a device using this material with that of devices employing the usual ZnS:Mn2+ material, MISM (metal-insulator-semiconductor-metal), ISM, and MSM devices were fabricated. Of these three devices, the singly-insulated device had the highest brightness, of 100 cd/m2, at a frequency of 5 kHz and a pulse height of 200 V. The brightness of this device is still lower than that of devices employing the usual ZnS:Mn2+. This is attributed to the smaller number of internal carriers and the smaller amount of carrier accumulation in the vicinity of the interface between the active luminescent layer and the insulating layer.
Emitter Probe Model for Plasma Coupling Phenomenon in Plasma-Coupled Device
Authors: Kusuda Yukihisa , Ito Ryouichi , Tanaka Shuhei , Hikasa Norio
Published: November 2005

Recently, to stabilize the operation of plasma-coupled device shift registers (PCD-SR), a emitter probe structure mounted on the PCD's emitter has been invented. The probe protrudes in the anti-transfer direction, and serves to pick up the lowered potential of the substrate around the preceding ON-PCD element. In this paper, the effect of the probe structure is investigated in detail, and a new quantitative probe model for the plasma coupling phenomenon is proposed. Especially with this model, it is considered that the deformation phenomenon of the Conductivity Modulation Region (CMR) induced by the probe current injection increases the coupling resistance. Using this model, the theory of the operation of the PCD-SR with the emitter probe structure is developed, and it is confirmed that this theory explains the experimental results.
Properties of a Microchannel Plate Operated in the Reflection Mode as an Energy- and Angle-Resolved Detector for Low-Energy Positive Ions
Authors: Koshida Nobuyoshi , Ohno Takao
Published: November 2005

Characteristics of a microchannel plate (MCP) operated in the reflection mode for detecting low-energy positive ions are studied in the range of the incident ion energy of E
i ≃20–150 eV. The output electron gain exhibits a sharp maximum at a certain voltage of a mesh collector. The maximum gain reaches about 103 even at E
i=19 eV as a result of the automatic preacceleration effect of the applied MCP voltage on incident ions. The gain is also highly sensitive to the ion's incident angle. These properties make it possible to discriminate between incident ion energies and to resolve its incoming direction.
Direct Detection of Radiocarbon Using Accelerator Techniques and Its Application to Age Measurements
Authors: Nakamura Toshio , Nakai Nobuyuki , Sakase Takao , Kimura Masaya , Ohishi Shoji , Taniguchi Makoto , Yoshioka Shigeo
Published: November 2005

Radiocarbon measurements by the direct detection of 14C atoms with the Tandetron accelerator mass spectrometer were begun in the autumn of 1983 at Nagoya University. The 14C dating of geological and archeological samples is routinely performed with a precision of ±1% (±83 years) using a carbon-silver target containing only 2–5 mg of carbon in measurements lasting 5 hours. The accuracy of a single 14C measurement was estimated by a reproducibility test to be ±1.34%. Radiocarbon ages measured with the Tandetron spectrometer for ten natural samples agreed well with those obtained by radioactivity measurements. The 14C background of the spectrometer limits the measurable age to less than 60000 y BP. The limit will be extended to about 82000 y BP if the 14C background is eliminated.
Cis-Trans Photoisomerization of Perinaphthothioindigo for Use as a Photo-Imaging Sensor Using Fluorescence under He-Ne Laser Excitation
Authors: Takahashi Tetsuhiko , Taniguchi Yoshio , Umetani Keiji , Yokouchi Hisatake , Hashimoto Michiaki , Kano Tsuyoshi
Published: November 2005

An imaging sensor based on the cis/trans isomerization of thioindigoid dyes is proposed. A photo-image (∼500 nm) is stored as a density distribution of the trans-form in the cis-form material, and read out as fluorescence (∼700 nm) from the trans-form by scanning with He-Ne laser (633 nm) excitation. As the fluorescence decay time of perinaphthothioindigo is 1.8 ns, the sensor permits rapid read-out. For light exposure L from 10-4 to 10-1 J/cm2 at 500 nm, the fluorescence intensity under laser excitation varies as L
0.8.
Analyses of PLZT Electrooptic Shutter and Shutter Array
Authors: Tanaka Katsuhiko , Yamaguchi Masami , Seto Hiroyuki , Murata Michihiro , Wakino Kikuo
Published: November 2005

The driving voltage and light transmittance in PLZT transverse electrooptic shutters composed of interdigital electrodes are investigated theoretically, with the electrode width, electrode gap, and wafer thickness being treated by the finite-element method. A new structure consisting of a combination of metal and transparent electrodes is presented, giving improved transmittance and driving voltage. Furthermore, the finite-element method is used to investigate the optimum driving voltage, fluctuation in light intensity, and S/N ratio in a one-dimensional optical shutter array. The combination of metal and transparent electrodes also brings about a low driving voltage, high transmittance and high S/N ratio in the shutter array.
Barrier Heights of Junctions between Amorphous Si-Ge-B and Crystalline GaAs
Authors: Murase Katsumi , Amemiya Yoshihito
Published: November 2005

The junctions between low-pressure CVD a-Si-Ge-B and n-type crystalline GaAs are characterized through detailed investigation of the barrier heights. The a-Si-Ge-B/GaAs junction is similar to the metal/GaAs junction. However, the barrier height of the former, which depends on the composition of the a-Si-Ge-B, is far larger than the maximum barrier height of the latter, and can be more than 1 V. The barrier height increases, while the work function of the a-Si-Ge-B decreases, as the Ge content of the a-Si-Ge-B increases. It is found that barrier heights estimated by the C-V method are larger than those estimated by the I-V method, and that the difference between the values estimated by the two methods is beyond the extent predicted by existing junction theories. The experimental results are interpreted in accordance with a generalized amorphous-crystalline junction model proposed in this paper.
Magnetooptic-Effect Analysis of Optical Fibers Using Intracavity Scheme: Application to KRS-5 in IR Regions
Authors: Sato Heihachi , Tsuchida Eiichi , Saito Mitsunori
Published: November 2005

A method of magnetooptic effect analysis using an intracavity method is proposed. The method is particularly suitable for optical fibers. If the lineshape parameters are known for a given laser, the Faraday and Voigt effects can be conveniently evaluated by analyzing the magnetooptically-induced intensity-variation of the oscillation output. The method has been successfully examined in KRS-5 fiber and crystal using He-Ne 3.39 µm and CO2 lasers, and the experimental results agree well with the theoretical estimates. This paper also describes a method of determining the lineshape parameters if they are not known for a particular laser.
Production of Slow Positrons Using an Electron Linac
Authors: Sueoka Osamu , Ito Yasuo , Azuma Toshiyuki , Mori Shigeki , Katsumura Yosuke , Kobayashi Hitoshi , Tabata Yoneho
Published: November 2005

Intense pulsed slow-positron beams have been produced using electron linac beams of energy 25 MeV. Slow positorons were counted by complete separation from strong flashed signals produced directly by the primary electron pulsed beam. The yield of low-energy positrons was estimated as 2×106slow positrons per second. The conversion efficiency of slow-positron production for 25 MeV electrons,ε, was 2.4×10-8, much lower than the value obtained by Howellet al.Several methods of overcoming the difficulties of practical application were attempted, and are discussed in the paper.
Low-Aberration Einzel Lens for a Focused-Ion-Beam System
Authors: Kurihara Kenji
Published: November 2005

A low-aberration electrostatic einzel lens for a finely-focused ion-beam system has been developed. The system design goal was a total aberration of 0.1 µm under the following conditions: beam half-angle, 2.5 mrad; working distance, 43 mm; beam energy spread, 10 eV; accelerating energy, 30 keV. The total aberration was reduced by using the following two guidelines: First, the einzel lens operated in the accelerating mode provides low chromatic and spherical aberrations. Second, spherical aberration is further reduced by enlarging the electrode gap spacing and central electrode bore. The design method for the accelerating mode lens to determine the lens dimensions which provide a low electrode voltage for the total aberration required is described.
Composition Dependence of Induced Anisotropy in Cobalt-Based Amorphous Alloys Containing 4d and 5d Transition Metals
Authors: Fukunaga Hirotoshi , Narita Kenji
Published: November 2005

The induced anisotropy, K
i, was measured in cobalt-based amorphous alloys containing 4d and 5d transition metals. The value of K
i for (Co1-x
TM
x
)0.9Zr0.1 (TM=Cr, Fe, Ni) alloys is much larger than that for metal-metalloid amorphous alloys, and shows a peak with increasing x. This behavior can be explained by the pair-ordering model, and the observed large K
i is attributed to strong pseudo-dipole interaction and weak non-magnetic interaction between magnetic atom pairs. K
i in (Co1-y
Zr
y
)0.9B0.1 and Co1-y
Zr0.1ME
y-0.1 (ME=Nb, Mo, W) alloys is also larger than that of metal-metalloid alloys, and decreases monotonically with increasing y. This decrease is closely related to the reduction of saturation magnetization, M
s, and the empirical low (K
i ∝M
s
3.2) is obtained. These behaviors are also discussed in the framework of the pseudo-dipole interaction model.
Elastic Anchoring Energy Related to Orientational Order Parameter of Nematic Liquid Crystal
Authors: Sugimura Akihiko , Kawamura Takao
Published: November 2005

The elastic strain energy density of liquid crystal molecules in the vicinity of the interface between a solid surface and nematic liquid crystal is investigated. The elastic strain energy density for various surface topographies is related analytically to the orientational order parameter by assuming a Gaussian distribution of liquid crystal molecules around the director along the direction of the periodic grooves on the substrate. From the measured orientational order parameter in the surface region and the analytical relation, we determine quantitatively the elastic strain energy density of the surface induced nematic liquid crystal.
Crystal Growth of CuGaS2 from Te, Te-Cu and Te-Cu-S Solutions
Authors: Hirakawa Kazuhiko , Nakamura Hiroshi , Aoki Masaharu
Published: November 2005

The solution growth of CuGaS2 single crystals using Te, Te-Cu and Te-Cu-S solutions has been studied. Crystallization from Te solution results in only small dark polycrystals. Large single crystals of CuGaS2 are obtained when a prescribed amount of excess Cu is added to Te solution (Te-Cu solution). Furthermore, by adding both excess Cu and excess S to Te solution (Te-Cu-S solution) large single crystals of CuGa2. with good crystallinity are obtained. The crystal structure and lattice constants of the grown crystals are measured by RHEED and X-ray diffraction methods. Applying Vegard's law to the lattice constants, we estimate the concentration of Te incorporated in the crystals and find it to be extremely small. The crystallinity of the grown crystals is examined by photoluminescence.
Pulsed-Laser Induced Desorption in GaAs: A Dynamic Pulse Mass Counting Study
Authors: Namiki Akira , Kawai Takaaki , Yasuda Yukio , Nakamura Tetsuro
Published: November 2005

Desorption of neutral atoms and molecules of pulsed laser irradiation of GaAs has been studied by means of a pulse mass counting technique. The translational temperature of desorbing molecules, As2 is found to be three times higher than that of As atoms. Remarkable angular dependence of translational temperature is also observed. These facts suggest that the translational temperature does not necessarily indicate the surface temperature when particles are desorbed.
UV Irradiation Effects on Chemical Vapor Deposition of SiO2
Authors: Takahashi Jun-ichi , Tabe Michiharu
Published: November 2005

Silica (SiO2) films have been deposited from a SiH4+O2+Ar system under 1849 Å irradiation by a low pressure Hg lamp without using Hg photosensitization. The oxygen partial pressure (P
O2
) dependence of the deposition rate has been measured in order to investigate the effects of 1849 Å irradiation.
In a low P
O2
region, it is found that the increase-maximum-decrease profile due to surface reaction in thermal CVD is modified under 1849 Å irradiation. The modification of the curve profile caused by 1849 Å irradiation is due to photodesorption of adsorbed oxygen molecules from the surface.
In a high P
O2
region, SiO2 deposition is observed under 1849 Å irradiation, while SiO2 is not deposited in thermal CVD. In this region the gas phase reaction is predominant.
Solubility and Diffusion Coefficient of Oxygen in Silicon
Authors: Itoh Yoshiko , Nozaki Tadashi
Published: November 2005

The solubility and diffusion coefficient of oxygen in silicon between 1000°C and 1375°C were examined by charged particle activation analysis with the16O(3He, p)18F reaction, in which oxygen was activated with an equal probability over the depth of up to 250 µm by a specially devised apparatus. Silicon wafers of known histories were heated in oxygen or argon for 12 to 473 hours, and the resultant oxygen depth profiles were determined by the activation, subsequent stepwise etching and18F activity measurement. The solubility thus obtained is given as 9.3×1021exp [-27.6 kcal mol-1/RT] at·cm-3; the diffusion coefficient has been found to be approximated as 3.2 exp [-67.1 kcal mol-1/RT] cm2s-1over 1150°C, under which the apparent activation energy seems to decrease with decrease of temperature.
Fluoride Barriers in Nb/Pb Josephson Junctions
Authors: Asano Hidefumi , Tanabe Keiichi , Michikami Osamu , Igarashi Masaru , Beasley Malcolm R.
Published: November 2005

Josephson tunnel junctions are fabricated using a new class of artificial barriers, metal fluorides (Al fluoride and Zr fluoride). These fluoride barriers are deposited on the surface of a Nb base electrode, which are previously cleaned using a CF4 cleaning process, and covered by a Pb counterelectrode. The junctions with both Al fluoride and Zr fluoride barriers exhibit good tunneling characteristics and have low specific capacitance. In the case of Zr fluoride, it is observed that reasonable resistances are obtained even at thickness greater than 100 Å. This phenomenon might be explained by tunneling via localized states in Zr fluoride.
Current Oscillation and Potential Oscillation in Semiconductors with a Dombbell-Shaped Structure
Authors: Endo Katsumi , Hirasawa Masao , Murayama Takashi , Oinuma Morihide , Kuwano Hiroshi
Published: November 2005

Current oscillation and potential oscillation in a semiconductor with a dumbbell-shaped structure are observed, and the mechanisms of the oscillations are investigated by varying the magnitude of the carrier densities. It is shown that a certain amount of the carrier densities are necessary to cause the current oscillation and that the potential oscillation is observed by pressing the probe on the surface of the narrow region even if the current oscillation of the narrow region is not observed.
Self-Generation of Toroidal Magnetic Flux in a Toroidal Z-Pinch
Authors: Sugisaki Kiwamu
Published: November 2005

Self-generation of toroidal magnetic flux is observed in a toroidal Z-pinch without any initial toroidal field. The direction of the generated toroidal flux does not correlated with that of the plasma current. More toroidal flux is generated for lower filling pressure. Toroidal flux sufficient to form a force free field configuration is obtained. A stationary state has not been reached within the present short discharge period (<120 µs), although magnetic field profiles give a gross force free field configuration.
Energy Distribution of Energetic Oxygen Atoms in the Sputtering of ZnO
Authors: Tominaga Kikuo , Kume Michiya , Yuasa Takayuki , Tada Osamu
Published: November 2005

Energetic neutral oxygen atoms bombarding the substrate in DC diode sputtering and DC planar magnetron sputtering were detected by a time-of-flight apparatus. In analyzing the time-of-flight spectrum, the energy distribution of the energetic oxygen atoms was computed by the fast Fourier transformation (FFT) method. The energy of the oxygen atoms bombarding the substrate was found to be distributed from 300 to e
V
T electron volts, the maximum energy which negative oxygen ions gain in the cathode fall in DC diode sputtering. The mean energy of the energetic oxygen atoms was estimated to be nearly e
V
T/2 electron volts. In planar magnetron sputtering, the flux of the energetic oxygen atoms showed a nearly monochromatic energy distribution.
Phase Transition of Lipid Multilamellar Aqueous Suspension under High Pressure I. Investigation of Phase Diagram of Dipalmitoyl Phosphatidylcholine Bimembrane by High Pressure-DTA and -Dilatometry
Authors: Utoh Shigenori , Takemura Tetsuo
Published: November 2005

The pressure and temperature phase diagrams of DPPC bilayers have been obtained by DTA and dilatometry. Under atmospheric pressure DPPC shows three phase transitions at 42°C, 36°C and around 18°C, corresponding to the main-, pre- and sub-transitions respectively. Throughout our experiments we discovered very interesting phenomena in these transitions due to the effect of pressure and are as follows. First, the presence of a tricritical point on the pre-transition line has been found at about 2.5 kbar and 78°C, where the first order transition changes to a second order transition. Second, the sub-transition could be observed under high pressure without annealing procedure which required to stock DPPC at about 0°C for three or four days under atmospheric pressure. Third, a new fourth transition below the sub-transition temperature has been discovered.
Raman Study on the Silicon Network of Hydrogenated Amorphous Silicon Films Deposited by a Glow Discharge
Authors: Hishikawa Yoshihiro , Watanabe Kaneo , Tsuda Shinya , Ohnishi Michitoshi , Kuwano Yukinori
Published: November 2005

A Raman study on the relation between the silicon bonds and the deposition conditions of amorphous silicon films is presented. Changes in the Raman spectra are investigated as functions of the deposition conditions. The Raman shift of the TO peak is found to become larger when the substrate temperature is increased. Numerical calculations on the local vibrations of the silicon network are carried out and it is shown that the change in the peak position is caused by the change in the stretching force constant of the silicon bonds.
XPS Studies on the Surface of Amorphous Pd80Si20 Alloys
Authors: Takagi Yasuo , Hwang Choll-Hong , Sekizawa Hisashi , Kawamura Kazutaka
Published: November 2005

The depth profiles of the chemical states and the compositions of Pd and Si near the surface region of amorphous Pd80Si20 alloys have been studied by XPS. It is found that analysis of the peak positions, the peak shapes, and the integrated intensities of XPS core-lines are very useful. The depth profile can be divided into three characteristic regions: bulk, transient, and skin. On passing through the transient region from the bulk to the skin, abundance of SiO2 increases while that of Pd decreases. In the skin region, amorphous SiO coexists with metallic Pd. To explain these experimental findings, a tentative model is proposed assuming an increase of the molar volume of Si on oxidation.
Influence of rf Plasma in Plasma Cleaning Process on Properties of Thin Superconducting Nb3Ge Films
Authors: Kato Yujiro , Rogalla Horst , David Bernd
Published: November 2005

The damage to A15 Nb3Ge films caused by Ar plasma or Ar+SF6 plasma cleaning has been studied by means of T
c and X-ray diffraction measurements. The degradation of the films was found to depend on the voltage, etching period, SF6 content, and film thickness. The drop in T
c was drastic for thinner films. Broadening of the X-ray diffraction peaks and a shift in the diffraction angle were observed after etching. An enlargement of lattice constant was detected for cathode voltages above 200 V for pure Ar plasma and below 100 V for SF6 plasma. The etch rate for Nb3Ge films in SF6 plasma was more than 100 times larger than that in pure Ar plasma.
Structural Studies on ZrO2-Y2O3 System by Electron Diffraction and Electron Microscopy I
Authors: Suzuki Susumu , Tanaka Michiyoshi , Ishigame Mareo
Published: November 2005

The oxygen-ion arrangements in 10–50 mol% Y2O3-ZrO2 at high temperatures have been investigated by electron diffraction and high-resolution electron microscopy. The observed diffuse scattering patterns are sorted into three types: 10, 20–30 and 40–50 mol% Y2O3. The characteristic oxygen-ion displacements for 10 mol% Y2O3, are found to agree completely with the findings of Faber et al., and those for 40–50 mol% Y2O3, can be explained in terms of a random mixture of two structures δ=0 and δ=1. The oxygen-ion displacements in these structures are expressed by the transverse waves whose wavenumber vectors are q=(π/a
0)[11̄0] and q=(2π/a
0)[11̄0], respectively. The structure δ=1 occupies 8% and 3% in volume for 40 and 50 mol% Y2O3, respectively. The random mixture of these structures forms micro domains of several nm in diameter, but does not develop into an ordered state upon being treated with heat.
An Oscillatory Desorption of Hydrogen and Alkali Atoms from α-Alumina
Authors: Ueda Kazuyuki , Kinoshita Keiji
Published: November 2005

Thermal desorption spectroscopy on α-alumina at elevated temperatures has been investigated by means of a rapid scanning mass spectrometry. An oscillatory desorption of hydrogen and alkali atoms has been found at temperatures higher than about 500°C. In this paper some origins of this novel phenomenon and the experimental setup are described.
Gold Particles Formed along <100 >-Step Lines of Sodium Chloride Crystals
Authors: Yanagihara Takashi , Yamaguchi Hiroyuki
Published: November 2005

The growth of gold particles deposited onto stepped surfaces of sodium chloride crystals has been studied by transmission electron microscopy. A great number of multiply-twinned particles and a few of pyramidal particles with an (001) orientation along the <100 >-step lines at a substrate temperature of 320°C or less were observed. The growth of these particles along the steps is discussed in terms of an atomistic nucleation theory and a model is proposed.
Measurement of MOS Leakage Conductance by Means of the Lateral Photovoltaic Effect
Authors: Shikama Tomokazu , Niu Hirohiko , Takai Munezo
Published: November 2005

The DC conductance g
t between the strong inversion layer and the substrate of an Al-SiO2-pSi MOS sample was measured as a function of the sample temperature T by the lateral photovoltaic method, and was found to be of the order of 10-5 ∼10-4 Ω-1cm-2.
The experiment showed that g
t behaves in two independent ways, possessing a part that increases with increasing T, and a part that increases with decreasing T; and that the former is dominant around room temperature, while the latter is dominant in a lower temperature range around 100 K.
The former behavior is accounted for by the recombination of carriers in the space-charge layer, while the latter is accounted for tentatively by the tunneling of electrons from the inverted conduction band to recombination centers in the forbidden band.
Thermodynamic Calculation of the VPE Growth of In1-xGaxAsyP1-y by the Trichloride Method
Authors: Seki Hisashi , Koukitu Akinori
Published: November 2005

A method of computation developed for analysing the equilibrium state of a multicomponent system has been applied to the epitaxial growth of In1-x
Ga
x
As
y
P1-y
carried out using the trichloride method. The composition regions in which the deposition is possible employing three crust sources are shown. The deposit compositions for practically important InAs-InP-GaAs and InAs-InP-GaP systems are computed as a function of the input mole ratios. It is shown that the composition of the deposit is almost the same for given input mole ratios in the trichloride and hydride methods, as in the In
x
Ga1-x
As growth, and that the precise control of the AsCl3 introduced to the Ga source is essential for preparing alloys lattice-matched to InP in a reproducibe fashion.
Optical Band-Pass Filter Using Accidental Isotropy and Optical Activity of AgGaSe2
Authors: Horinaka Hiromichi , Sonomura Hajimu , Miyauchi Takeshi
Published: November 2005

AgGaSe2 is an optically active and birefringent crystal, and has a specific wavelength at which an optical isotropy happens to occur. An optical band-pass filter with polarizer-AgGaSe2 crystal-polarizer sandwich structure is fabricated by using these properties, in which the central wavelength lies in 811 nm and the band width is 3.8 nm. In this type of filter, the change in the band width is made possible by considering the crystallographic orientation of crystal plate used, and suppression of the side-bands can be done by piling the same type of filters. Also in this paper, a change in the central wavelength from 497 nm to 811 nm effected by using AgGaS2-AgGaSe2 alloy is predicted.
Amorphous Silicon Static Induction Transistor
Authors: Ueda Masato , Hirose Masataka , Osaka Yukio
Published: November 2005

A hydrogenated amorphous silicon (a-Si:H) Schottky-gate static induction transistor (SIT) is proposed and its characteristics are calculated for the case that the gap-state distribution in a-Si:H is constant near the Fermi level. It is found that an a-Si:H SIT with a gate spacing of about 5 µm can yield a sufficiently high ON/OFF current ratio of more than 108 when the gap-state density near the Fermi level is 5×l015 cm-3eV-1. The cut-off frequency of an a-Si:H SIT is expected to exceed a few MHz.
Density Accumulation of a Magnetized Current-Carrying Plasma Caused by a Metal Disk
Authors: Kawaguchi Motoichi , Suzuki Shigeru , Tanaka Hiroyoshi , Enjoji Hiroshi
Published: November 2005

Experiments on the stationary disturbance of a weakly ionized current-carrying plasma caused by a floating metal disk in a longitudinal magnetic field are described. Electron and ions in the plasma form longitudinal counter-streams. Experimental results are presented for the upstream region of electrons relative to the disk disturber, where the disturbance is characterized by accumulation of plasma particles. The transverse and longitudinal lengths of the plasma accumulalion are measured. The peak value of the plasma density increases with B/p (B: the magnetic field, p: pressure of neutral helium gas). In the disturbed region the potential is lower than in the surrounding area. The mechanism for the disturbance is discussed as related to the suppression of the electron current caused by the disk with the flow patterns of the magnetized plasma particles.
Changes of Volume and Surface Compositions of Polymethylmethacrylate under Electron Beam Irradiation in Lithography
Authors: Samoto Norihiko , Shimizu Ryuichi , Hashimoto Hatsujiro
Published: November 2005

The change of the content of oxygen and carbon in Polymethylmethacrylate (PMMA) under electron beam irradiation is investigated by Auger electron spectroscopy (AES) whereby we estimate the characteristic energy deposition of the decrement of oxygen to be 0.8–1.2×103 eV/nm3. It is also confirmed that cooling of PMMA considerably reduces the elimination rate of oxygen and that the decrement of the thickness of PMMA film under electron beam irradiation is closely related to the change of oxygen content. Moreover, it is shown that the PMMA alters from the positive resist to the negative resist as determined by observing thickness changes.