bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Interpretations of the Gap State Density Determined from the Field Effect and Capacitance-Voltage Characteristics of Amorphous Semiconductors
Authors: Suzuki Tohru , Osaka Yukio , Hirose Masataka
Published: November 2005

An exact theory for the calculation of the electronic density of bulk gap states in amorphous semiconductors from field effect and capacitance-voltage measurements is presented. The analytical expression for the density of the gap states is given as a function of the surface potential of amorphous semiconductors. It is also shown that the influence of surface states on the measured gap states can be completely eliminated by combining a capacitance-voltage method with a field effect technique.
Possibility of Use of Liquid Crystals as Optical Waveguide Material for 1.3 µm and 1.55 µm Bands
Authors: Kawachi Masao , Shibata Noriyoshi , Edahiro Takao
Published: November 2005

This letter describes an experimental investigation on the transmission characteristics of a liquid crystal optical waveguide in the 0.7 µm–1.7 µm spectral range. The scattering loss decreases from 10 dB/cm to about 2 dB/cm as the wavelength is increased from 0.7 µm to more than 1.3 µm. This indicates the potential use of liquid crystals as an active waveguide material for integrated optics operating at 1.3 µm and 1.55 µm, at which wavelengths the liquid crystals also have low absorption loss windows.
CW Laser Annealing of Polycrystalline Silicon on SiO2 and Effects of Successive Furnace Annealing
Authors: Kugimiya Koichi , Fuse Genshu , Inoue Kaoru
Published: November 2005

CW Ar laser annealing was carried out to reduce the resistivity of polycrystalline silicon implanted with light doses of 1×1012-5×1014B+/cm2. Laser annealing, actually laser melting, and successive furnace annealing effectively reduced the resistivity to almost that of single crystal silicon. TEM, OM and stress observations revealed that the reduction was due primarily to the grain growth of polycrystalline silicon and secondarily to stress relief, from 9×109 dyne/cm2 to 5×109 dyne/cm2, caused by annealing. Grain growth of up to about 3×100 µm and bamboo-joint-like growth were observed.
Efficient Laser Absorption in Low Density Foam Target
Authors: Okada Kazuyuki , Sakabe Shuji , Shiraga Hiroyuki , Mochizuki Takayasu , Yamanaka Chiyoe
Published: November 2005

High laser absorption rate was obtained for a low density foam layered pellet. The idea that a microcell structure of plastic foam will increase the absorption rate is proposed to explain this result and discussed with computer simulation results. Such target is considered to have almost no dependence on laser incidence angle or laser wavelength.
Inelastic Low Energy Electron Diffraction Measurements of Hydrogen Adsorbed Si (001) Surfaces: 2×1:H and 1×1: :2H
Authors: Maruno Shigemitsu , Iwasaki Hiroshi , Horioka Keiji , Li Sung-Te , Nakamura Shogo
Published: November 2005

We identified the monohydride phase Si(001)2×1:H and the dihydride phase Si(001)1×1: :2H by angle resolved electron energy loss profiles and I–V curves of 00-beam. For the 2×1:H-saturated surfaces, S3 transition from back bond surface state was observed although S1 transition from dangling bond surface state disappeared. For the 1×1: :2H surface, S2 and S3 transitions from back bond surface states completely disappeared but S1 transition was observed. We clearly distinguished hydrogen induced loss peaks for the two surfaces: the peaks were at 8 eV for the 2×1:H surface and at 7 eV for the 1×1: :2H surface.
A Mechanical Model for Magnetic Bubble Domain Current-Sheet Devices
Authors: Hayashi Nobuo
Published: November 2005

A simple mechanical device has been constructed for the rapid simulation of magnetic bubble domain current-sheet devices. The device consists of a small ferrite magnet with a magnetic moment of 4.8 G·cm3, and layers of perforated aluminum films whose sizes match the diameter of the magnet. The magnet was placed in a light plastic boat, which was floated on the surface of a viscous fluid. A sequenced electric current of 0.1 A/cm was able to move the magnet at a speed of ∼0.1 cm/s. The outline of the device and experimental results showing the validity of the device are given.
Conducting Polymer Prepared from Teflon
Authors: Yoshino Katsumi , Yanagida Shozo , Sakai Toshihiko , Azuma Takayuki , Inuishi Yoshio , Sakurai Hiroshi
Published: November 2005

Conducting polymer is prepared from teflon by treatment with a THF solution of alkali-naphthalide. The electrical conductivity of this film is of the order 10-5-10-4 (Ω·cm)-1 which is higher than that of teflon by more than ten orders of magnitude and comparable with that of trans (CH)
x
. The observed small activation energy of the conductivity seems to indicate that this material is slightly doped during the preparation process, as in the case of (CH)
x
.
Monolithic 1×4 Array of Uniform Radiance AlGaAs–GaAs LED's Grown by Molecular Beam Epitaxy
Authors: Sugahara Tomonobu , Wada Osamu , Fujii Toshio , Hiyamizu Satoshi , Sakurai Teruo
Published: November 2005

Extremely uniform radiance AlGaAs–GaAs LED array was prepared by molecular beam epitaxy. About 80% of the 1170 diodes tested in a wafer had a light intensity variation of less than ±6%. Monolithic 1×4 LED array chip was coupled to a 1×4 fiber array arranged on a V-grooved Si substrate. The variation among light outputs of four fiber ends was as small as ±3%.
Reduction of Shear Strength and Phase-Transition in Shock-Loaded Silicon
Authors: Goto Tsuneaki , Sato Toshiyuki , Syono Yasuhiko
Published: November 2005

Shock wave profile measurements on Si were performed to 60 GPa. Three shock wave structures arising from dynamic yielding and structural transition were observed between 19 and 30 GPa. The Hugoniot elastic limit (HEL) is determined to be 8.4 GPa in the [100] direction and 5.6 GPa in the [110] and [111] directions. Unusually low shock velocities just above HEL, compared with the bulk sound velocity, are successfully analyzed by assuming complete loss of shear strength in the yield state. The phase transition pressure is determined to be 13.4±.2 GPa, which compares favorably with the semiconductor-metal transition observed at static pressures.
Hysteresis Loop in Current-Voltage Curve for BaPb0.7Bi0.3O3 Josephson Junction Array in a Microwave Field
Authors: Ito Minoru , Enomoto Yoichi , Suzuki Minoru , Murakami Toshiaki , Inamura Takahiro
Published: November 2005

The microwave-induced, quantized high dc voltage of about 2 mV across the unbiased BaPb0.7Bi0.3O3 Josephson tunnel junction array is observed. The nearly rectangular hysteresis loop due to the voltage generation appears in the current-voltage curve. The induced voltage polarity can easily be switched by an external pulse current input signal of only 50 A/cm2. This voltage switching can probably be exploited in the Josephson junction array as a future logic element.
Effects of Nitrogen Incorporation on Gap-State Density in Chemically Vapor-Deposited Amorphous Silicon
Authors: Sasaki Goro , Kondo Makoto , Fujita Shizuo , Sasaki Akio
Published: November 2005

Temperature dependence of dark conductivity and field in a chemically vapor-deposited amorphous SiN
x
(x≃0.2) alloy are presented. The a-SiN
x
film exhibits little hopping conduction and large field effect as compared with undoped CVD a-Si. The gap-state density near the Fermi level in the CVD a-SiN
x
film is evaluated as 2×1018 cm-3 eV-1 which is one-fifth of that in an undoped film.
Reactive Ion Beam Etching Using a Broad Beam ECR Ion Source
Authors: Matsuo Seitaro , Adachi Yoshio
Published: November 2005

A broad beam ion source using a microwave electron cyclotron resonance (ECR) discharge has been newly developed, giving high reliability in operation. The ion source operates at gas pressures higher than about 3×10-5 Torr, and an ion current density of 1 mA/cm2 is obtained at an ion extraction voltage of 1000 V. By introducing C4F8 and SiCl4 into the ion source, SiO2 and Al are etched at rates greater than 1000 Å/min, with high selectivities and high-accuracy pattern transfer.
The Electrostrictive Unimorph for Displacement Control
Authors: Abe Kazuhide , Uchino Kenji , Nomura Shoichiro
Published: November 2005

Rectangular unimorphs for displacement control have been fabricated using PMN-based electrostrictive ceramics instead of conventional piezoelectric ceramics. Bending response of the unimorph has been investigated under DC or AC applied voltage. The response has also been checked under mechanical load. The unimorph with 0.45PMN- 0.36PT-0.19BZN, which is the best choice at this moment, reveals a large displacement at the free end up to 20 µm under an applied cyclic voltage of 400 V with little hysteresis.
Oxygen Donors Developed around Dislocations in Silicon
Authors: Koguchi Masamitsu , Yonenaga Ichiro , Sumino Koji
Published: November 2005

Plastic deformation of Czochralski silicon crystals at elevated temperature produces both acceptors and donors simultaneously. The former are ascribed to dislocations and the latter to the oxygen atmospheres around dislocations. The energy levels of the deformation-induced donors are determined by Hall measurements. The oxygen atmospheres are found to be very stable and not to easily transform to precipitates of cristobalite by annealing at 900°C.
Work Function Study of Fe Adsorption on Fe (001) and (110)
Authors: Nakanishi Shigemitsu , Kanno Masataka , Horiguchi Tetsuo
Published: November 2005

The two-dimensional island growth of iron atoms adsorbed onto (001) and (110) surfaces of an iron single crystal was studied at various temperatures (110 K–R. T.) by measurement of the work function change. The (110) surface showed considerable decrease of the work function with increasing iron coverage (θ<0.5) and the curves of the change were interpreted in terms of the law, Δφ∝√θ, on the island growth. The mean dipole moment of a single adatom was estimated to be 1 Debye at the low temperature (110 K). On the other hand, the (001) surface showed no work function change even at low temperature.
Properties of Tellurium Doped Vacuum Evaporated CdS Thin Films
Authors: Banerjee Ratnabali , Ray Swati , Barua A. K.
Published: November 2005

The effects of doping of vacuum evaporated CdS thin films with tellurium have been investigated. The changes in dark conductivity, photoconductivity, Hall mobility and carrier concentration due to doping have been studied. The optical density and structure of these films have also been determined. From the results obtained for dark conductivity, Hall mobility and carrier concentration it has been suggested that the effect of doping with Te is to introduce deep donor levels in CdS. However, as the concentration of Te is increased, levels are introduced on both sides of these deep donor levels, the lower ones overlapping the valence band and the higher ones going nearer the conduction band. The optical density and structure of these films as determined by X-ray diffraction are similar to those reported earlier undoped CdS films.
Submicron-Length Tungsten-Gate Self-Aligned GaAs FET
Authors: Matsumoto Kazuhiko , Hashizume Nobuo , Atoda Nobuhumi , Nishimura Kazuhiro , Tomizawa Kazutaka , Kurosu Tateki , Iida Masamori
Published: November 2005

A first submicron-gate ion-implanted self-aligned GaAs FET that has ever been made is reported. The FET has a 0.5 µm-long, 0.24 µm-thick tungsten gate which was fabricated by lift-off process and subsequently served as a mask for n+-implantation. The self-aligned FET showed the transconductance 2.4 times as large as that of a conventional FET of the same dimensions. The source-gate breakdown voltage was in excess of –3 V.
Composition Control of AlxGa1-xAs and New Type of Superlattice by Pulsed Molecular Beam
Authors: Kawabe Mitsuo , Matsuura Nobuyuki , Inuzuka Hajime
Published: November 2005

A new composition control method of molecular beam epitaxy is studied in Al
x
Ga1-x
As using a pulsed molecular beam. The AlAs mole ratio in the ternary compound is controlled by changing the duty ratio of a pulsed aluminum molecular beam. The photoluminescence shows no particular difference between the films grown by the pulsed molecular beam and a conventional-continuous molecular beam. A composition control system is made and a new type of superlattice is fabricated.
LEC Growth Technique for Homogeneous Undoped Semi-Insulating GaAs Single Crystals with in-situ Melt Purification Process
Authors: Terashima Kazutaka , Nakajima Hiroaki , Fukuda Tsuguo
Published: November 2005

It was found that GaAs melt can be purified in-situ by our new method of bubbling distillation technique. The degree of the purification can be detected by the measurement of the electric conductivity of the melt. With this technique homogeneouse undoped semi-insulating 2 inches in diameter GaAs single crystals can be grown with high reproducibility.
Observation of Electroluminescence from Amorphous Silicon Solar Cells at Room Temperature
Authors: Lim Koeng Su , Konagai Makoto , Takahashi Kiyoshi
Published: November 2005

Electroluminescence from a-Si pin, pi(B-doped)n, and nip solar cells was observed at room temperature (300 K) for the first time. The electroluminescence spectrum of the nip cell showed very broad with a peak at 1.31 eV or slightly less. The external quantum efficiency of the nip cell was 10-5% at 300 K. Electroluminescence intensity from this cell was stronger than that from the pin cell. It became clear that this can be attributed to the difference in the current transport mechanism of the nip and pin cells. A pin cell whose i-layer was slightly boron doped, the pi(B)n cell, gave a stronger electroluminescence intensity than a usual pin cell.
Temperature Dependence of Electron-Irradiation Induced Amorphization of NiTi Alloys
Authors: Mori Hirotaro , Fujita Hiroshi
Published: November 2005

Electron-irradiation induced amorphization of NiTi alloys has been investigated in a temperature range from 50 to 393 K by high voltage electron microscopy with the following results: A crystalline-amorphous transition occurs when the total dose of electrons reaches a certain value. The critical value decreases with decreasing irradiation temperature and becomes almost constant with about 2×1025 e/m2 below 100 K. Process of the transition is also revealed.
An Optical Heterodyne Method for Measurement of the Raman-Nath Parameter of Ultrasound
Authors: Nagai Satoshi , Iizuka Kozo
Published: November 2005

An optical heterodyne method is presented for measuring the Raman-Nath parameter of ultrasound. A light beam passes through a phase grating induced by ultrasound and then is recombined with another light with frequency shifting. The interference distribution of the two light beams is measured by a photodetector placed in the Fresnel region. The Raman-Nath parameter is extracted from the beat signal with the frequency component centered at the difference of the two light beams. A principle is described and favorably compared with experimental results for narrow-band pulsed ultrasound.
Effect of Uniaxial Stress on the Photoluminescence from Plastically Deformed Silicon
Authors: Suezawa Masashi , Sumino Koji , Nishina Yuichiro
Published: November 2005

Investigations have been conducted on the effects of uniaxial stress on the spectrum and the polarization of photoluminescence from plastically deformed silicon crystals. Among four luminescence lines, D1, D2, D3 and D4 associated with deformation-induced defects, D1 and D2 show spectral responses to uniaxial stress which are different from those of D3 and D4.
Electrical Properties of Conducting Polymer, Poly-Thiophene, Prepared by Electrochemical Polymerization
Authors: Kaneto Keiichi , Yoshino Katsumi , Inuishi Yoshio
Published: November 2005

Poly-thiophene perchlorate is prepared electrochemically in an electrolyte of 0.5 M AgClO4 and 0.2 M thiophene in acetonitrile. Dark greenish film with the complex of ca. [C4H2S(ClO4)0.26]
x
is obtained. The electrical conductivity along the film surface is about 0.6 Ω-1cm-1.
Effects of Electron Irradiation on Electrical Conductivity of Polyacetylene
Authors: Yoshino Katsumi , Hayashi Shigenori , Inuishi Yoshio
Published: November 2005

Influence of electron beam irradiation on the electrical conductivity of I2 doped trans-(CH)
x
and its temperature dependence are studied. The electrical conductivity of I2 doped sample decreases and its activation energy increases with increasing irradiation dose. Imperfections such as chain breaks or cross-linkings strongly affect the conductivity of a low dimensional conductor like (CH)
x
.
Electrical Activation of B Ions Implanted in Deposited-Amorphous Si during Solid Phase Epitaxy
Authors: Ishiwara Hiroshi , Naruke Kiyomi , Furukawa Seijiro
Published: November 2005

A novel doping technique in solid phase epitaxy of Si is presented, in which impurity ions are implanted in deposited-amorphous films and electrically activated during epitaxial growth of the films. It has been found in boron-implanted samples that the electrical activity is very high at annealing temperatures higher than 600°C and that the ions do not penetrate deeply by the channeling effect nor redistribute by thermal diffusion. An anomalous result that the sheet carrier concentration is higher than the implanted boron dose has also been found and its origin is phenomenologically investigated.
On the Mechanism of Domain Refinement due to Scratching
Authors: Pfützner Helmut , Zehetbauer Michael
Published: November 2005

As well known, defined scratching of soft magnetic materials results in domain refinements and thus in reduction of anomalous eddy current losses. However, the present paper shows that scratching a grain oriented HI-B sheet causes a stress configuration corresponding to slight bending which would lead to domain widening. Moreover, it is demonstrated that regions of domain refinement due to scratches of restricted length are clearly demarcated by the scratch endings. These experiments indicate that changed stress configurations are nonrelevant for resulting refinements which, rather, are due to stray field generation. Effects are discussed by a theoretical model resulting in refinements especially of wide domains which is in agreement with presented experimental data.
Residual Donor Impurities in MO-CVD Gallium Arsenide
Authors: Ohyama Tyuzi , Otsuka Eizo , Matsuda Osamu , Mori Yoshifumi , Kaneko Kunio
Published: November 2005

Residual donor species as well as their concentrations in undoped MO-CVD GaAs have been investigated using far-infrared laser magneto-optics with intrinsic photoexcitation. Both donor and acceptor concentrations have been precisely determined for various samples grown under different conditions. It has been found that the main donor species in MO-CVD GaAs are Si and Ge, the relative concentrations of which depend on the partial pressure of AsH3.
A New Method for Estimating the Voltage-Current Characteristics in a Plasma-Dielectric-Metal System
Authors: Yamaguchi Shinji , Sawa Goro , Ieda Masayuki
Published: November 2005

A new method was proposed for estimating the voltage-current characteristics of dielectric film sandwiched between plasma and metal electrodes. An experimental technique for obtaining these characteristics was then established using the probe characteristics which were measured by a single probe covered with plasma polymerized film in nitrogen gas plasma.
Lattice Image Observation of Extended Dislocations in CdS by High Resolution Electron Microscopy
Authors: Suzuki Kunio , Takeuchi Shin , Kanaya Koichi
Published: November 2005

Atomistic configurations of extended glide dislocations multiplied on the basal plane in CdS have been observed for the first time by high resolution electron microscopy. From the widths of the 60°-dislocation (∼9.0 nm) and the screw dislocations (∼3.6 nm), the energy of the intrinsic stacking fault has been estimated to be 13±2 mJ/m2.
Epitaxial Growth of Ge Films onto CaF2/Si Structures
Authors: Asano Tanemasa , Ishiwara Hiroshi
Published: November 2005

Heteroepitaxial Ge/insulator/Si structures have been prepared by vacuum evaporation of CaF2 and Ge onto heated (111) and (100) oriented Si substrates. CaF2 films with high crystalline perfection and smooth surface were formed on (111) and (100)Si at substrate temperatures of 800°C and 600°C, respectively. Ge films were deposited onto the CaF2/Si structures at 400°C to 600°C. Higher Ge deposition temperature resulted in increased Ge surface roughness but improved Ge crystalline quality. Both the crystalline quality and the electrical properties of the Ge films on CaF2/Si(100) structures were superior to those of the Ge films on CaF2/Si(111) structures.
A Mechanism for Inducing Ion Current in a Theta-Pinch
Authors: Hirano Kei-Ichi
Published: November 2005

It is demonstrated that net ion current may be induced in the implosion phase of a θ-pinch if the hydrgen plasma were contaminated with impurities. The force appears to induce a hydrogen flow in the direction of the electric field accompanied by an opposite flow of impurities both of which are further accelerated by the plasma implosion keeping the null total angular momentum. These counter flows of hydrogen and impurity ions generate a net ion current since the former carries a larger ion current than the latter due to the fact that impurities are not fully ionized in a θ-pinch.
A Monte-Carlo Simulation for Neutral Beam Probing of Plasma Current Profile
Authors: Masamune Sadao , Okada Hiroyuki , Yamagiwa Mitsuru , Okamoto Masao , Nishihara Hiroshi
Published: November 2005

The profile of birth points of the secondary ions in the NOVA II plasma was calculated when probed by a neutral beam. The orbits of secondary ions were calculated and the resultant traces, curves formed by tracks of the ions impinging the detector plate, were obtained for the purpose of the neutral beam probing of plasma current profile. A slight reduction of the sensitivity of the trace to the plasma current profile due to the toroidal field ripple, as well as the spread of the trace due to the finite divergence of the probing beam will bring about no substantial difficulty in identifying the plasma current profile.
Lamella to Dendrite Transition in Solidifying Hypereutectic Fe–FeSi Alloy Films
Authors: Asahi Nobuo
Published: November 2005

The critical condition for the transition from lammellar to dendritic structures in hypereutictic Fe–FeSi alloy films, ranging in composition from 35 to 40 at·%Si, has been determined by means of unidirectional solidification. The critical condition is expressed by the following relation;

G/R=1.6×107C0+4.7×106

where G is temperature gradient in a melt at the liquid-solid interface, R is the solidification rate and C
0 is the initial composition of Si in the melt. The liquid diffusion coefficient obtained using the above result was 4.1×10-5 cm2/s.
SIMS and ESCA Studies of Electrochromic WO3 Thin Films
Authors: Muramatsu Hiromochi , Itoh Toshiki , Watanabe Atsushi , Hara Kunihiko
Published: November 2005

The mechanism of electrochromic coloring and bleaching reaction in vacuum-deposited amorphous WO3 thin film was studied, and it was found that the stoichiometry and the hydrogen content in the films did not change during the reaction, and that the oxygen extraction model proposed by Chang and the hydrogen injection model by Faughnan were not valid. This result coincides with Deneuville's model, i.e. the hydrogen content within the film does not change in the reaction and that the coloring mechanism is explained by the transfer of hydrogen from a passive site to an active site within the films.
MOCVD-Grown Al0.5In0.5P–Ga0.5In0.5P Double Heterostructure Lasers Optically Pumped at 90 K
Authors: Suzuki Tohru , Hino Isao , Gomyo Akiko , Nishida Katsuhiko
Published: November 2005

Undoped Al0.5In0.5P–Ga0.5In0.5P double heterostructure was grown on (100) GaAs by metalorganic chemical-vapor deposition for the first time. A mirror-like grown surface was obtained. Over ten-times stronger photoluminescence-intensity was gained from the sandwitched Ga0.5In0.5P layer, than that from a single epitaxially-grown Ga0.5In0.5P-layer on (100) GaAs, indicating that high-quality Al0.5In0.5P–Ga0.5In0.5P heterointerfaces are formed in the double heterostructure. A lasing action by optical pumping with an argon ion laser was observed in the double heterostructure at 90 K. The observed stimulated emission wavelength was 6470 Å.
Surface Roughness Measurement with Speckle Intensity Distribution Detected Using a Linear Image-Sensor
Authors: Horiuchi Toshio , Tomita Yutaka , Kammel Roland
Published: November 2005

An experimental study is made of the far-field intensity distribution of speckles caused by rough surface. The maximum intensity of speckles formed by optical Fourier transform is detected with a linear image-sensor (28 µm×28 µm×512). The ratio of the maximum intensity to the total power of the scattered light is found to be a scale for the roughness of samples. The method is applicable to the measurement of surface roughness, independent of correlation length and reflectance variation caused by contamination of surface.
New Surface Structure of Pd on Si(111) Studied by Low-Energy Ion-Scattering Spectroscopy and LEED-AES
Authors: Yabuuchi Yasufumi , Shoji Fumiya , Oura Kenjiro , Hanawa Teruo , Kishikawa Yozo , Okada Satoshi
Published: November 2005

A new Pd-induced √3×√3–R30° superstructure on Si(111) has been studied by low energy ion scattering spectroscopy (ISS) combined with LEED-AES. It has been observed that the Pd atoms giving rise to the √3 structure can be detected by AES but not by ISS, indicating that the Pd atoms are incorporated into the Si substrate. Possible models of the √3–Pd structure are presented.
Recent Results on 500 MHz Superconducting Cavities at KEK
Authors: Kojima Yuzo , Furuya Takaaki , Nakazato Toshiharu
Published: November 2005

Two 500 MHz spherical cavities built from Nb were tested. Locations of weak spots at breakdown field levels were detected and surface processing was repeated to remove the weak spots. Q
0 and the accelerating field gradient were improved after each reprocessing.Q
0=4.1–4.2×109 and E
acc=6.5 MV/m at 4.2 K, Q
0=3.2–4.8×1010 and E
acc=7.0 MV/m at 1.8 K were obtained for both cavities.
The Effects of H and F on the ESR Signals in a-Si
Authors: Ishii Nobuhiko , Kumeda Minoru , Shimizu Tatsuo
Published: November 2005

The effect of hyperfine interaction between a dangling bond and nearby H or F atoms in a-Si is calculated by using a simple molecular orbital method. The isotropic hyperfine structure constant of about 20 G or 43 G is obtained in the case of H or F attachment, respectively, at the nearest neighbor site to the Si atom with a dangling bond. It is considered, by comparing the calculated results with the observed ones, that dangling bonds are located avoiding H or F rich regions in a-Si.
Liquid-Phase Epitaxial Growth of AlxGa1-xAs1-yPy on (100) GaAs0.61P0.39
Authors: Fujimoto Akira , Shimura Mikihiko , Hasuda Hirohiko , Yamashita Shigeaki
Published: November 2005

The growth conditions of Al
x
Ga1-x
As1-y
P
y
on (100) GaAs0.61P0.39 substrate by the step-cooling liquid-phase epitaxial method have been investigated. The growth conditions and properties of Al
x
Ga1-x
As1-y
P
y
epitaxial layers are reported. Epitaxial layers with mirror-like surfaces and flat interfaces were obtained at several compositions of Al
x
Ga1-x
As1-y
P
y
(x=0.28 y=0.38, x=0.47 y=0.36). The distribution coefficients of Zn and Te in Al0.28Ga0.72As0.62P0.38 at 790°C were approximately 0.017 and 0.09, respectively. The activation energy for the free-hole generation of Zn-doped Al0.28Ga0.72As0.62P0.38 was about 26 meV.
Planar Defect in A15 Structure Observed in Cr–Si Fine Particles
Authors: Ishimasa Tsutomu , Fukano Yasushige
Published: November 2005

A new planar defect in the A15 structure was found in fine particles formed by the evaporation of Cr–Si alloy in Xe gas. Electron microscopic analysis showed that the planar defect lies on the {100} plane and the displacement vector due to the defect is <±1/8, 1/2, 0>a. A probable model of the defect is proposed.
Homoepitaxial Growth of ZnTe by Horizontal Open-Tube Method
Authors: Nishio Mitsuhiro , Nakamura Yoshihiro , Ogawa Hiroshi
Published: November 2005

The vapor-phase epitaxy of ZnTe was carried out in H2, Ar and I2 gas ambients by the horizontal open-tube method. The depletion rate of the ZnTe source and the growth rate on (110), (111)A and (111)B ZnTe substrates are described here as functions of the carrier gas flow rates, and the molar ratios of I2 to H2 and of Ar to H2. The values of the depletion rate and the growth rate decreased in the following order: ZnTe–H2–I2≃ZnTe–H2>ZnTe–Ar and ZnTe–H2–I2\gtrsimZnTe–H2>ZnTe–Ar system, e.g., the depletion rates were 3.0, 3.0 and 2.4 mg/min, and the growth rates were 0.30, 0.24 and 0.18 µm/min respectively, when the source temperature was kept at 923°C, the substrate temperature at 862°C and the carrier flow rate at 100 ml/min. The surface pattern of the epitaxial layer was strongly influenced by the growth temperature and the surface orientation.
Magnetic Fluid's Anomalous Pseudo-Cotton Mouton Effects about 107Times Larger than That of Nitrobenzene
Authors: Taketomi Susamu
Published: November 2005

The magneto-birefringence of magnetic fluid thin films of 12 µm and 25 µm were studied and anomalous phase differences were found when an external magnetic field was applied normal to the direction of light propagation. The order of the phase differences of the films was about 107times larger than that of nitrobenzene, which is known to show a large Cotton-Mouton effect. We attribute these phenomena theoretically to a rod-like chain formation of the ferrite particles in the magnetic fluid thin films and derive expressions for the phase difference and absorption. There is a definite difference in theH-\vartheta curves between theory and experiment in the rising gradient nearH=0.
Estimation of the Ultimate Frequency Stability of Semiconductor Lasers
Authors: Ohtsu Motoichi , Fukada Hiroyuki , Tako Toshiharu , Tsuchida Hidemi
Published: November 2005

The frequency stabilities of 0.8 µm AlGaAs lasers were estimated by using the Allan variance as a measure of the stability. The contributions of the quantum noise (the spontaneous emission, carrier, and current noise) and additional noise (current source noise and temperature noise) are given. The highest frequency stability of the free-running laser was estimated to be 6.3×10-11 at an integration time of 0.1 s. It is shown that the frequency stability of the stabilized laser is limited by the quantum noise. The estimated results were compared with the experimental results and with the estimated stability of 3.39 µm He–22Ne lasers. The derivations of the spectral width from the frequency stability are also given. The narrowest limit of the spectral width was estimated to be 5.5 MHz (HWHM) for I/I
th=1.3, while the corresponding experimental result was 6.2 MHz for a channeled-substrate planar (CSP)-type laser.
Electrical Properties of ZnSe
Authors: Satoh Shiro , Isshiki Minoru , Igaki Kenzo
Published: November 2005

The electrical conductivity and electron concentration were measured as a function of deviation from stoichiometry in high-purity undoped and Cl-doped ZnSe single crystals. The In and Cl concentrations in high-purity undoped ZnSe were estimated using activation analysis. It was determined that the shallow donors are due to native defects.
A Pellet Model of DT Ignitor and DD Fuel for an ICF Reactor without Tritium Breeding Blanket
Authors: Ido Shunji , Tazima Teruhiko
Published: November 2005

A pellet concept of a DT ignitor and DD fuel for an ICF reactor without a tritium breeding blanket is analytically examined under the condition that T is bred through the DD reactions. There is the additional restriction that the tritium breeding ratio in a pellet is unity, including the in situ DT burn in the DD region. Model calculations show that sufficiently high pellet gain can be obtained in a DT-DD pellet, when fuel ρR increases to ∼40 g/cm2 and the fraction of energy released in the DD region becomes dominant. One-dimensional neutronics calculations carried out for a reference pellet model with ρR∼40 g/cm2 show that the neutron heating in the compressed pellet model is evident and the total energy of the neutrons escaping from the pellet is reduced from ∼2000 MJ to 330 MJ for a microexplosion of ∼3000 MJ.
A Potential Disturbance of a Magnetized Current-Carrying Plasma Caused by a Floating Disturber
Authors: Kawaguchi Motoichi , Tanaka Hiroyoshi
Published: November 2005

The potential disturbance caused by a floating disturber in a current-carrying magnetized plasma is analyzed theoretically. The equations used are the Boltzmann relation for electrons and the continuity equation for a collisional flow of ions, which lead to a Laplace's equation by using a function transformation. The solution shows that a potential overshoot appears, and the criterion for this overshoot is given. The peak value of the overshoot and the position of the peak are compared with experimental results. The mechanism for the overshoot is discussed, and it is concluded that it originates from the rarefaction effect of the electron density in the shadow region of the disturber in the E-driven flow of electrons.
On the Core Behavior of Dislocations in the Covalent Semiconductors C, Si and Ge
Authors: Masuda Kin-ichi , Kojima Kenichi , Hoshino Toshiharu
Published: November 2005

We use a tight-binding (TB) type electronic theory to calculate the core structure and core energy of both screw and 60° dislocations in the covalent semiconductors C, Si and Ge. To represent the repulsive interaction between atomic sites i and j, arising mainly from the core orthogonalization, we introduce a Born-Mayer potential. From the total (attractive and repulsive) energy calculations, we investigate the stability of dissociated partial dislocations. We show that the glide-set dissociated dislocations are more stable than the corresponding shuffle-set perfect dislocation, in agreement with recent experimental observations. The calculated results are also compared with available experimental results on the structure images and the dynamic properties of dislocations. In addition, we investigate the electronic states (sp configuration) of the dangling-bond-like states (DBLS) near the core of the partial dislocations, and discuss the validity of using fixed sp3 hybrid orbitals for calculating the dislocations.
Secondary Ion Analysis of Silicon under Ar+ Ion Etching in Chlorine and Fluorine Flux
Authors: Ikawa Eiji , Kurogi Yukinori
Published: November 2005

Secondary ion analysis was performed on a silicon surface during Ar+ ion bombardment under simultaneous exposure to chlorine or fluorine flux. The Cl+, Cl2
+, F+ and F2
+ secondary ion intensities increased with the amount of reactive gas flux. However, other secondary ion intensities, such as SiCl+ and SiF+, decreased at large reactive gas flux. In a large reactive gas flux, the Cl+ and F2
+ secondary ion intensities were related to the Si etching yield. The amounts of reactive atoms adsorbed on one silicon atom are the same in the large reactive gas flux region. The etching rate ratios of silicon, silicon dioxide and silicon nitride had almost the same value, no matter how much the Cl2 flux increased. No dependence of the etching rate on the crystalline orientation was observed.
Monte Carlo Calculations of Diffusion Constant in n-InP
Authors: Aishima Asuo , Fukushima Yoshifumi
Published: November 2005

Ensemble Monte Carlo simulations are carried out to ascertain the magnitudes of the parallel and perpendicular diffusion constants in n-InP and their dependence on the electric field. The two-dimensional locations of 1000 electrons in real space after many accelerations by the electric field and collisions with phonons are illustrated in order to clarify the anisotropy in electron diffusion behavior. It is also demonstrated how both the parallel and perpendicular diffusion constants are affected by impurity scatterings. It is found that, because of the randomizing nature of impurity scatterings, both the parallel and perpendicular diffusion constants in n-InP with higher impurity density are greater than those in n-InP with lower impurity density.
Effect of Annealing on Electrical and Optical Properties of Si-Implanted GaAs
Authors: Shigetomi Shigeru , Matsumori Tokue
Published: November 2005

The annealing behavior (up to 500°C) of semi-insulating GaAs implanted with 2×1014 Si ions/cm2 at 200 keV has been investigated by measuring the sheet resistivity, Hall effect and optical absorption. In the samples annealed at temperatures below 450°C, the sheet resistivity, Hall mobility and optical absorption show the characteristics of amorphous semiconductors. The sample annealed at 500°C recovers to a partially-compensated n-type semiconductor, and the Hall mobility can be explained as scattering due to residual defects.
Titration Method for Measuring Fluorine Atom Concentration in Microwave Plasma Etching
Authors: Ninomiya Ken , Suzuki Keizo , Nishimatsu Shigeru
Published: November 2005

A titration method has seen developed to measure the concentration of fluorine (F) atom in microwave plasma etching. A rapid reaction of F atoms with H2 gas is used as a titration reaction to determine the absolute F atom concentration. Applying the present method to SF6 microwave discharge, the F atom concentration is measured under various discharge conditions. The F atom concentration is 2.9-4.0×1011 cm-3 at a typical operating pressure of 6.7×10-2 Pa and a microwave power of 200 W. It is confirmed that relative changes in the concentration agree well with those obtained with the optical spectroscopic method.
Heteroepitaxial Growth of Group-IIa-Fluoride Films on Si Substrates
Authors: Asano Tanemasa , Ishiwara Hiroshi , Kaifu Noriyuki
Published: November 2005

Growth conditions and structures of vacuum-evaporated heteroepitaxial CaF2, SrF2 and BaF2 films on (111) and (100) oriented Si substrates have been investigated. Single crystal CaF2 films are grown on both Si(111) and (100) substrates at temperatures of 600–800°C and 500–600°C, respectively. CaF2 films on Si(111) have crystal orientations rotated 180° about the normal to the substrate surface. SrF2 and BaF2 films of good crystalline quality are grown on Si(111) at temperatures around 600°C, but are composed of two types of crystallites which have orientations either idential to those of the substrate or rotated 180° on the substrate surface about the surface normal. SrF2 and BaF2 films grown on Si(100) contain (111) oriented crystallites, and, in an extreme case, completely (111) oriented BaF2 films were grown on Si(100).
Intensity vs Time Profiles of Photostimulated Exoelctron Emission from Scratched Aluminum
Authors: Shigekawa Hidemi , Hyodo Shin-ichi
Published: November 2005

Aluminum sheets were scratched with steel needles of different diameters, and photostimulated exoelectron emission (PSEE) therefrom was studied. It was found that the PSEE change with time after scratching can be classified into five types, which differ in the number of intensity peaks, intm(the time required to reach the first peak), and in the mode of decay. Experiments showed that these five types were correlated with the type of scratching as well as with the surrounding gas pressure. The pressure dependence oftmis explained in terms of the “two process model” previously proposed by the suthors.
Field-Emission-Current Fluctuations from a (100) Vicinal Plane of Tungsten with Adsorbed Xenon Molecules
Authors: Okano Tatsuo
Published: November 2005

The surface diffusion of Xe molecules on an atomically rough (110) vicinal plane of W was studied by the field-emission current-fluctuation method. The probed area was located in a brightly-emitting region around a dark (110) plane. The autocorrelation function of the current fluctuation was measured for temperatures ranging from 80 to 87 K. The apparent surface diffusion coefficients deduced from the correlation time are strongly coverage-dependent and show a maximum at θ=0.4. The activation energy E
d and the pre-exponentials D
0 of the surface diffusion coefficient at θ=0.7 are 2.5 kcal/mol and 2×10-6 cm2/s, respectively. For θ<0.5, the apparent value of D
0 is more than 6×102 cm2/s and is much larger than the value estimated from the hopping model of surface diffusion.
A Capacitance Investigation of InGaAs/InP Isotype Heterojunction
Authors: Ogura Mototsugu , Mizuta Masashi , Onaka Kiyoshi , Kukimoto Hiroshi
Published: November 2005

We have measured deep levels near the InGaAs/InP heterointerface by DLTS and C-V method. Three deep levels, E1, E2 and E3, have been found near the heterointerface, whose activation energies are 0.17 eV, 0.37 eV and 0.54 eV, respectively. The concentrations of E2 and E3 rapidly decrease when approaching the heterointerface from the InP, indicating that the two levels are located only in the InP substrate. The E1 level, on the other hand, can be found only near the heterointerface. The density of the E1 level is well correlated with the interface charge density which is determined by the C-V analysis. Both of the densities are dependent on the degree of the lattice mismatch between the InGaAs epitaxial layer and the InP substrate.
Electrical Transport and Breakdown of Poly-p-Phenylenesulfide
Authors: Yoshino Katsumi , Yun Mun Soo , Ozaki Masanori , Kim San Hyon , Inuishi Yoshio , Kyoukane Jun
Published: November 2005

Electrical transport and dielectric breakdown of PPS are studied. Electrical resistivity of PPS film at room temperature is about 1018 Ω·cm and super-linear current-voltage characteristics are observed, which can be explained in terms of either Poole-Frenkel or Schottky effects. Temperature dependence of the conductivity changes remarkably at the glass transition temperature around 90°C. The activation energies of the conductivity are about 0.3 eV and 2.1 eV below and above this temperature, respectively. Dielectric breakdown strength of PPS is relatively insensitive to the temperature compared to the case for PE. Though breakdown strength of PPS is lower than that of PE below room temperature, it becomes higher at temperatures above 100°C.
Electrochromism in a Thin-Film Device Using Li2WO4 as an Li-Electrolyte
Authors: Yoshimura Tetsuzo , Watanabe Masaki , Koike Yoshio , Kiyota Kohei , Tanaka Masao
Published: November 2005

A thin-film electrochromic device using Li2WO4, which is shown to be an Li electrolyte by the fact that the coloration response is independent of the atmosphere, is found to exhibit quick response (coloration: 50 ms, bleaching: 200 ms). The spontaneous coloration is suppressed by the deposition of a WO3 film at low pressure (10-6 Torr), and by using a metal with a small work function as the counter-electrode. The threshold voltage for coloration increases as the work function of the counter-electrode material decreases. Supressions of the spontaneous coloration and the threshold voltage shift are induced by the potential difference between the WO3 and the counter-electrode introduced by the difference in the Fermi levels. Complete bleaching of the device is achieved in a device with a WO3 film deposited at 10-6 Torr at a substrate temperature of 160°C, while it is not achieved in a device with a WO3 film deposited at 10-4 Torr. This suggests that Li2WO4 is colored by proton injection from WO3 into Li2WO4, which arises from the electrolysis of water in the WO3 film deposited at high pressure.
Direct Energy Input to Compressor for Inertial Confinement Fusion
Authors: Mouri Akihiro , Ikuta Kazunari , Tazima Teruhiko
Published: November 2005

An effective method for driving ICF pellet compression is proposed where neither laser beam nor charged particle beam is necessary but rather high electric pulse power is directly input into a vacant space between a shell tamper and its enclosed pellet. Electrons emitted from the pellet surface produce a dense, hot plasma on the inner side of the tamper. Photons and particles of the plasma irradiate the pellet surface and give rise to an effective ablation-driven compression. This direct energy input to compressor (DEIC) can be done efficiently and makes it easier to picture an ICF reactor.
Quantitative Analysis by Auger Electron Spectroscopy
Authors: Shimizu Ryuichi
Published: November 2005

A short review is presented of the theoretical background of a physical model for the quantification of Auger electron spectroscopy (AES) for surface analysis. The recent studies on the data-base for the inelastic mean free paths (IMFP) by Seah and Dench and systematic calculations of the backscattering factors (R) by Shimizu and Ichimura have now enabled standard quantitative corrections comparable to those widely used in electron probe microanalysis, to be accomplished.
For quantitative corrections of wider practical use, the present paper proposes the use of functional representations of the backscattering factors for different angles of incidence (ψ) for primary energies ranging from 3 to 10 keV as follows: R=1+(2.34-2.10Z
0.14)×U
-0.35+(2.58Z
0.14-2.98) for ψ=0°, R=1+(0.462-0.777Z
0.20)×U
-0.32+(1.15Z
0.20-1.05) for ψ=30°, R=1+(1.21-1.39Z
0.13)U
-0.33+(1.94Z
0.131.88) for ψ=45°, where U is the ratio of the primary energy to the binding energy, and Z is the atomic number of a sample.
NMR of Xe Adsorbed on Graphite
Authors: Shibanuma Takashi , Asada Hiromu , Ishi Shin-ichi , Matsui Toshiji
Published: November 2005

The NMR of 129Xe adsorbed on exfoliated graphite was observed in three different adsorbed phases: multilayer, 2D (two-dimensional) solid and 2D liquid phases. The chemical shifts observed with the 2D solid and the 2D liquid were much greater than those with the respective 3D phases, which may be attributed to Xe-graphite interactions. The difference in the shift between the two 2D phases was found to be of the same order of magnitude as in the 3D Xe. When the chemical shift in the multiayer phase is compared with that in 3D Xe, the multilayer phase seems to lie between the 3D solid and 3D liquid with respect to atomic density.
Calculation of Impurity Concentrations in LPE InP Layers
Authors: Takanohashi Tsugunori , Komiya Satoshi , Yamazaki Susumu , Umebu Itsuo , Akita Kenzo
Published: November 2005

A mobility analysis of ionized impurity scattering is performed for the calculation of the impurity concentrations of liquid-phase-epitaxial (LPE) InP layers. The donor and acceptor concentrations (N
d
, N
a
) calculated by the method explain the temperature dependence of the Hall coefficient of InP layers in the range of carrier concentration n=2×1015-2×1016 cm-3 well. By applying the calculation to Hall data on undoped and lightly Cd-doped InP specimens with a growth temperature of 650°C, the effective distribution coefficient of Cd is determined as K
Cd=1.8×10-3.
Active Beam Scattering Method for Measurement of Ion Temperature in JFT-2 Tokamak Plasma
Authors: Takeuchi Hiroshi , Matsuda Toshiaki , Nishitani Takeo , Shiho Makoto , Konagai Chikara , Kimura Hironobu , Maeda Hikosuke
Published: November 2005

The capability of determining ion temperature by neutral beam scattering was investigated, and the ion temperature of an ohmically-heated JFT-2 tokamak was determined using a neutral beam scattering system. In the scattering experiment, a continuous beam of 15 keV hydrogen atoms was used with a scattering angle of 4°C. The ion temperature obtained by this method agreed with that deduced from measurement of passive charge-exchange neutrals. The influence of impurities on the scattering spectrum was investigated, and it was found that the difference between the intensity estimated from Rutherford scattering theory and the observed intensity increased with the atomic number of the target particle. It was established that the fact that impurity ions did not contribute to the scattering intensity arose from the ionization of the neutral beam by collision with impurity ions.