bluuebunny/crossref_metadata_2025 huggingface dataset:
LPE Growth and Pulsed Room Temperature Laser Operation of In1-xGaxAszP1-z on (100) GaAs1-yPy (y\cong0.39)
Authors: Shimura Mikihiko , Fujimoto Akira , Yasuda Hirohiko , Yamashita Shigeaki
Published: November 2005

Lattice-matched In1-x
Ga
x
As
z
P1-z
epitaxial layers with various compositions (0.72≦x≦0.89, 0.03≦z≦0.37) have been grown on VPE (100) GaAs1-y
P
y
(y\cong0.39) by ramp cooling LPE (initial supercooling 10°C, growth temperature 790°C and cooling rate 0.5°C/min). Energy band gaps of these alloys have been determined by photoluminescence spectra at room temperature. Double heterostructures grown on the basis of conditions as presented here have lased at approximately 640 nm at room temperature. The characteristic temperature of the threshold current density is as large as 90 K.
Frequency Dependence of the Submillimeter-Wave Response in the Tunnel-Type and Bridge-Type Josephson Junctions
Authors: Morita Seizo , Takaki Satoru , Imai Syozo , Takeuti Yosihisa , Mikoshiba Nobuo
Published: November 2005

We have fabricated ultrasmall tunnel-type Josephson junctions with Nb–SnO
x
–Sn film point-contacts. Using these junctions, we have measured for the first time the Shapiro steps in the submillimeter-wave region and have compared the strength of steps of this junction with that of the bridge-type Nb–Sn ingot point-contacts. We found that the tunnel-type junction shows a sharper Riedel peak than the bridge-type junction.
Preparation of Nd-Doped SiO2 Glass by Plasma Torch CVD
Authors: Namikawa Hiroshi , Arai Kazuo , Kumata Ken , Ishii Yoshiro , Tanaka Hiroaki
Published: November 2005

Silica glass has not been fully characterized as a host material for glass lasers. To evaluate the intrinsic fluorescent characteristics of Nd-doped SiO2 glass, a plasma torch CVD system was specially designed for the preparation of clear high purity glasses. Both of the observed fluorescences of Nd3+ (4F3/2–4I9/2 and 4F3/2–4I11/2) consist of a fast (τ≃0.35 µs) and a slow (τ≃450 µs) decay component. The spectral features and intensity of the former remarkably depend on Nd concentration and preparation conditions, while those of the latter are similar in every sample and its fluorescence peak positions distinctly shift to a wavelength longer than those observed in ordinary multicomponent glasses.
Spectroscopic Measurement of Cyclotron Radiations from Linear Device with Field-Gradient along the Axis
Authors: Nagatsu Masaaki , Inuzuka Hiroshi , Tsukishima Takashige
Published: November 2005

A spectroscopic measurement is carried out of the second harmonic electron cyclotron radiations from a linear turbulent-heating device at an angle oblique to the external magnetic field, from which a radial profile of the electron temperature T
e is evaluated. An enhancement of T
e is observed around the periphery of the cylindrical plasma, presumably due to the skin effect.
High Temperature Stable W-GaAs Schottky Barrier
Authors: Matsumoto Kazuhiko , Hashizume Nobuo , Tanoue Hisao , Kanayama Toshihiko
Published: November 2005

The effect of annealing a W-GaAs (Se+ implanted) Schottky diode at high temperatures was investigated. The diode showed an excellent stability against annealing. The ideal factor n and the barrier height φB of the diode stayed more or less constant at values of 1.1–1.2 and 0.73 V, respectively, for the temperature variation of 800°C–950°C. Using He+ backscattering analysis, it was shown that the interdiffusion in W and GaAs couples takes place at 900°C.
Optical Amplification due to Parametric Interaction of Four Waves with a Four-Level System
Authors: Tsukakoshi Motowo
Published: November 2005

Four-wave parametric interactions in a four-level system are treated using semiclassical theory. Line-shape functions for a weak probe field and three resonant pump fields are presented and are evaluated numerically in a model case of equalized interaction energies and relaxation rates. For sufficiently intense pump fields, the line shape splits into five peaks, and negative absorption, i.e. amplification, occurs in some frequency regions of the probe field.
Orientation Dependence of LPE Growth Behavior of GaxIn1-xP on (100) and (111)B GaAs Substrates
Authors: Kume Masahiro , Ohta Jun , Ogasawara Nagaatsu , Ito Ryoichi
Published: November 2005

Liquid Phase Epitaxy (LPE) of Ga
x
In1-x
P on (100)- and (111)B-oriented GaAs substrates has been studied at the growth temperature of 735°C. The results indicate that the Ga distribution coefficient, growth rate and luminescence half-widths depend significantly on the substrate orientation. These types of behavior are qualitatively similar to those reported earlier for the growth of Ga
x
In1-x
As on InP.
Nonlinear Modification of Radiation Patterns of Electron Plasma Waves
Authors: Ohnuma Toshiro
Published: November 2005

Nonlinear modification of radiation patterns of electron plasma waves from a circular planar mesh is observed with an increase of an exciting radio-frequency field in an unmagnetized plasma.
An Airlock for a Resistively Heatable Specimen of a Field Ion Microscope and an Atom-Probe
Authors: Nishikawa Osamu , Horie Shiro
Published: November 2005

An airlock assembly, which enables the specimen of a field ion microscope and an atom-probe to be heated resistively, is described. The typical pressure rise during specimen change is 10-5 Pa. Shortly after this specimen change a vacuum of 10-7 Pa is recovered and a new specimen can be examined in less than one hour.
Formation of n-Layer in In0.53Ga0.47As by Si Implantation
Authors: Kawata Haruo , Nishi Hidetoshi , Bamba Yasuo , Sakurai Teruo , Hashimoto Hisao
Published: November 2005

Electrical activtaion behavior of Si atoms implanted into LPE-grown In0.53Ga0.47As layer is discussed. Activation of Si atoms occurs during 500–700°C heat treatment, corresponding to the annealing out of the lattice disorders as observed by the channeling analysis. Annealing at 700°C of 1×1014 Si ions cm-2 implanted InGaAs resulted in the formation of an n-layer having a maximum electron mobility of 7000 cm2/V·s at the corresponding free electron concentration of 8×1017 cm-3, which is comparable to the data obtained for the epitaxially grown layers.
Deep Levels Associated with Nitrogen in Silicon
Authors: Tokumaru Yozo , Okushi Hideyo , Masui Tsumoru , Abe Takao
Published: November 2005

Two deep levels at E
c-0.19 eV and E
c-0.28 eV are found in nitrogen-doped silicon, in which nitrogen is doped during crystal growth by the float-zone method. The E
c-0.19 eV level has an electron capture cross section of 8×10-17 cm2 and the E
c-0.28 eV level has that of 5×10-16 cm2. The concentrations of the former and latter levels are about 0.1 and 0.01% of the doped nitrogen concentration (∼1015 cm-3), respectively.
Forbidden Reflection Intensity in Electron Diffraction and Its Influence on the Crystal Structure Image
Authors: Nagakura Sigemaro , Nakamura Yoshio , Suzuki Toshiaki
Published: November 2005

The forbidden reflection intensity from crystals containing the two-fold screw axis depends strongly on the incident beam direction, and this influences the contrast of crystal structure image. Taking cementite (Fe3C, orthorhombic, Pbnm) as an example, intensity calculation and image simulation have been made. It is shown that the forbidden reflection intensity increases with the tilt angle of the incident beam direction from the zone axis and becomes comparable with the normal reflection intensity. The forbidden reflection introduces a contrast modification with lattice period to the structure image in the direction of the two-fold screw axis. These results are in accordance with observations.
Liquid Phase Epitaxial Growth of CuGaTe2 on ZnSe from Bi Solution
Authors: Takenoshita Hiroshi , Imai Susumu , Nakau Tanehiro , Nishira Masatoshi
Published: November 2005

A CuGaTe2 layer was grown on ZnSe by liquid phase epitaxy from Bi solution. This combination produced a large lattice misfit and considerable lattice distortion. The optimum growth conditions were as follows: a maximum temperature of 530°C, a cooling rate of 0.5°C/min and the substrate orientation ZnSe(111)Se. The epitaxial growth was confirmed by electron diffraction, and the results of Hall measurements at 300 K gave σ=12.5 Ω-1-cm-1, µH=33.0 cm2/Vs and N
A=2.40×1018 cm-3. From EPMA, (CuGaTe2)1-x
–(2ZnSe)
x
alloys were found to form a solid solution. The thickness of the mixed crystal layer was 1.0 µm.
Determination of the Built-in Potential in a-Si Solar Cells by Means of Electroabsorption Method
Authors: Nonomura Shuichi , Okamoto Hiroaki , Hamakawa Yoshihiro
Published: November 2005

The applicability of the low-field electroabsorption (EA) method to determine the built-in potential of a-Si solar cells has been experimentally demonstrated. As theoretically predicted, plots of the EA signal amplitude versus the bias voltage for various modulation voltages exhibit straight lines intercepting the bias voltage axis at a single definite value corresponding to the built-in potential. The information of the built-in potential thereby obtained is used as a known parameter in the analysis of a-Si solar cells.
Accurate Determination of the Lifetime and the Quenching Rate Constant of Kr2F by the Excitation of Very Short Electron Beam Pulse
Authors: Ueda Ken-ichi , Hara Hideo , Kaneda Shoji , Takuma Hiroshi
Published: November 2005

The lifetime and quenching rate constant of Kr2F by F2 were directly determined from the decay rate of the fluorescence emitted after excitation of a high current electron beam pulse of 3 ns duration. The ambiguity caused by the overlapping of other processes was removed by exciting the medium with a very short electron beam pulse and selecting an experimental condition through examination by our newly revised computer code. The natural lifetime was determined as 210±20 ns, and the quenching rate constant by F2 as (1.8±0.1)×10-10 cm3s-1.
The Topographic Observation of Coloured Quartz under the High Electrostatic Field
Authors: Gouhara Kazutoshi , Bessho Yoshinori , Yasuda Kenji , Kato Norio
Published: November 2005

An anomalous contrast in the X-ray topograph of X-ray irradiated (coloured) quartz was observed when a high electrostatic field (5 kV/mm) was applied to it. The boundary between the coloured and non-coloured parts was particularly enhanced. The observations with different g-vectors sugest that the strain gradient is induced normally to the boundary. It could be bleached off completely by X-ray irradiation without electric field for 30 minutes, and also by keeping the specimen at 500°C for 3 hours. The conceivable cause of this phenomenon is the reverse piezoelectric effect of an inhomogeneous electric field induced by a space charge.
Dynamic Recording and Readout Characteristics of GdTbFe Using a Modified Magneto-Optical Disk Exerciser
Authors: Nagao Yasuyuki , Tanaka Shinsuke , Tanaka Fujio , Imamura Nobutake
Published: November 2005

Amorphous ternary GdTbFe alloy films with a Kerr rotation angle of 0.38°–0.41° were prepared by rf sputtering on glass disks with a diameter of 115 mm. Thermomagnetic recording and readout experiments were carried out on these disks using a modified magneto-optical disk exerciser. The bit density of a few tens Mb/cm2 and the carrier-to-noise ratio (C/N) of 38 dB at 2.048 Mb/s (NRZ) were attained. It was found that a smaller spot diameter is desirable for readout than that for recording. Furthermore, primitive measurements of bit error rate were made at 1.536 and 2.048 Mb/s (NRZ), and values of the order of 10-5 were obtained.
Effects of Photoelectrons and Auger Electrons on Contrast and Resolution in X-Ray Lithography
Authors: Saitoh Yasunao , Yoshihara Hideo , Watanabe Iwao
Published: November 2005

The effects of photoelectrons and Auger electrons from the X-ray mask on the contrast and resolution were investigated in the replication of submicron resist patterns in X-ray lithography. A resist thinner than 550 Å was exposed to electrons generated by an Si–N membrane. The effect of electrons from the Au absorber is observed even with a 1 µm thick Au absorber pattern, because of the continuous radiation generated, shorter than the characteristic radiation. A polymer film coating on the Au absorber pattern increases the contrast of the mask, because electrons from the X-ray mask are absorbed by the polymer film.
Ion-Induced Auger Electron Emission from Si Surface
Authors: Saiki Koichiro , Tanaka Shoji
Published: November 2005

Ion-induced Auger electron spectrum of Si was investigated for low energy (2–10 keV) rare gas (Ar or Kr) ion incidence. The angular distribution of ejected Auger electrons was studied for the first time. An integral energy distribution measured with high energy-resolution (Δ
E=0.1 eV) revealed that the atomic-like peaks become prominent with an increase of emission angle. The Auger peak feature in the integral spectrum and the emission angle dependence of the Auger peak intensity proved useful in discussing the origin of the Auger electrons.
Preparation of Low Loss Fluoride Glass Fibers
Authors: Mitachi Seiko , Kanamori Terutoshi , Miyashita Tadashi
Published: November 2005

By using a “build-in casting” method, homogeneous waveguide structure with a smooth core-claddeing interface was formed in fluoride glass fiber. A minimum loss of 37 dB/km at 2.6 µm band was obtained by establishing a 5.4 cladding core diameter ratio and 0.33% relative refractive index difference between core and cladding.
High-Rate Deposition of a-Si: H Film Using the Decomposition of Mono-Silane
Authors: Nakayama Yoshikazu , Natsuhara Toshiya , Nagasawa Nobuo , Kawamura Takao
Published: November 2005

High-rate deposition technique of a-Si: H films for an electrophotographic photoreceptor using a glow discharge decomposition of SiH4 is described. The deposition parameters are optimized on the basis of results that the emission intensity ratio of the species H to SiH in the plasma is a function of the rf power and flow rate of SiH4 by which a hydrogen bonding state in the resultant film is controlled. An a-Si: H film with a suitable hydrogen bonding state for excellent electrophotographic properties is prepared at the high deposition rate of 5 µm/h. It is also found that the deposition rate is proportional to the emission intensity of SiH.
Effect of Cell Width on the Structure of Williams Domain
Authors: Hirata Shoji , Tako Toshiharu
Published: November 2005

The direction of Williams domain in an AC or a DC electric field (WDAC, WDDC) is perpendicular to the rubbing direction (RD) or inclines at an angle of about 60 degrees from the RD, respectively. When a cell width is as narrow as the period of WD, it is found that the direction of WDAC inclines from the perpendicular direction and the inclination becomes larger as the cell width narrows, while there is only the WDDC with even numbered stripes perpendicular to the RD. These different phenomena are considered from the viewpoint of the symmetry of the flow structure. It is seen that the positively charged carrier flows mainly in WDDC.
Magnetic Properties of Sm–Co Thin Films Prepared by Oblique Incidence
Authors: Tanaka Takao , Yoshida Makoto , Takahashi Seiichi , Tasaki Akira
Published: November 2005

Ferromagnetic thin films of the Sm (0–45%)–Co system were prepared by the oblique incidence method. It was found that saturation flux density and coercive force of thin films showed a continuous dependency on the concentration of Sm. Coercivity of 1.9 kOe was obtained in Sm 30%–Co thin film prepared at an incident angle of 45°C. From the experimental results, it is considered that the nonequilibrium phase of Sm–Co is realized in the films.
Photoinduced Optical Changes in Amorphous Silicon-Carbon Alloy Prepared by Reactive Sputtering in an Atmosphere of Propane
Authors: Iida Seishi , Ohki Shigehisa
Published: November 2005

Photoinduced absorption edge shifts towards lower and higher energies, i.e. photodarkening and photobleaching, have been observed for the first time in a-Si
x
C1-x
: H films prepared by the reactive sputtering of Si in a gaseous mixture of C3H8–Ar. Photodarkening is induced by band gap illumination in vacuum and photobleaching by illumination in air. The dependence of the effects on composition suggests that carbon atoms are responsible. The effects are probably related to photostructural changes in the films, being accompanied by changes in film thickness. The photobleaching is related to the formation of C=O bonds which appear in the infrared absorption.
Conical Pinched Electron Beam Diode for Intense Ion Beam Source
Authors: Matsukawa Yoshinobu , Nakagawa Yoshiro
Published: November 2005

For the purpose of improvement of the pinched electron beam diode, the production of an ion beam by a diode with electrodes in a conical shape was studied at low voltage operation (∼200 kV). The ion beam is emitted from a small region of the diode apex. The mean ion beam current density near the axis at 12 cm from the diode apex is two or three times that from an usual flat parallel diode with the same dimension and impedance. The brightness and the power brightness at the origin are 450 MA/cm2 sr and 0.12 TW/cm2 sr respectively.
AuAl2 Thin Film Resistors for Josephson Integrated Circuits
Authors: Morohashi Shin'ichi , Imamura Takeshi , Shibayama Hikou , Hasuo Shinya
Published: November 2005

Films of an intermetallic compound AuAl2 with CaF2 structure have been proposed as a new type of resistors for Josephson integrated circuits made of a lead alloy. The value of the sheet resistance of AuAl2 films is about four times larger than that of AuIn2 films with the same structure at a film thickness of 500Å. AuAl2 films are stable against the lead alloy base electrode of the Josephson junction.
Effect of Adsorbates on the Trapping Properties in Hydrogenated Amorphous Silicon Films
Authors: Yamaguchi Masaaki
Published: November 2005

We have carried out the measurements of thermally stimulated currents in order to clarify the effect of adsorbates such as oxygen and water on the trapping properties in a-Si: H. The active trapping levels in samples annealed at 150°C are estimated to be located at 0.36 eV and 0.41 eV for adsorption of oxygen and 0.49 eV for that of water on the surface of a-Si: H below the edge of the conduction band, respectively. Moreover, a trapping level which may be associated with bulk properties has been found at 0.22 eV.
Electrical Properties of Si-Doped AlxGa1-xAs Layers Grown by MBE
Authors: Ishikawa Tomonori , Saito Junji , Sasa Shigehiko , Hiyamizu Satoshi
Published: November 2005

Electrical properties of Si-doped Al
x
Ga1-x
As layers grown by MBE were investigated as a function of AlAs mole fraction (0≦x≦0.5). Although ionization energy of Si donor remained constant at a few meV in the range of 0≦x≦0.25, it rapidly became larger with increasing x for x≧0.25. It was found to be 60 meV for x=0.3, which is the composition used in HEMT. The overall trend was similar to the case of Sn- or Te-doped Al
x
Ga1-x
As layers. However, the ionization energy was found to be independent of doping concentration, unlike the case of Sn-doped Al
x
Ga1-x
As layers grown by MBE.
Heteroepitaxial Growth of GaP on a Si (100) Substrate by Molecular Beam Epitaxy
Authors: Kawanami Hitoshi , Sakamoto Tsunenori , Takahashi Tetsuo , Suzuki Eiichi , Nagai Kiyoko
Published: November 2005

Heteroepitaxial films of GaP were grown on Si (100) substrates by molecular beam epitaxy (MBE). The GaP films were single crystalline in the growth temperature range from 300°C to 590°C. These films had a tendency to have flat surfaces at lower growth temperatures. Sn was doped as n-type dopant of GaP films in the carrier concentration range from 3×1016 cm-3 to 8×1018 cm-3. The n-GaP/p-Si heterojunction showed rectifying properties. Hall mobilities of the n-GaP films at room temperature were 100–30 cm2 V-1 s-1 for the carrier concentration range from 3×1016 cm-3 to 8×1018 cm-3.
Defect Eliminating Method Using Si3N4 Film Patterns
Authors: Mada Yoichi
Published: November 2005

Microdefects elimination in CZ silicon wafers by using patterned Si3N4 film fabricated on the back of silicon wafers has been studied. Si3N4 film patterns 1 mm and 0.1 mm square with 2500Å thickness were fabricated on the back of wafers and the defect density on the front on the wafers after annealing at 850°C was investigated. It was found that square patterns of Si3N4 film on the back of silicon wafers effectively eliminated crystalline defects. The gettering effect depends on the size of square Si3N4 patterns.
Fluxon Waves on a Josephson Transmission Line
Authors: Tateno Hiroshi , Sakai Shigeki
Published: November 2005

The exact behavior of stationary fluxon waves propagating along a Josephson transmission line having arbitrary amounts of uniformly applied bias current and shunt dissipation is explained geometrically in the state plane (voltage vs. phase difference plane). It is shown that there are only two kinds of fluxon wave, one being a solitary wave and the other an infinitely long train of fluxon waves, and that the solitary wave velocity never reaches the velocity of electromagnetic waves on a dissipationless transmission line as far as dissipation is concerned.
Cr-Related Intracenter Luminescence in GaAs: Cr
Authors: Fujiwara Yasufumi , Nishino Taneo , Hamakawa Yoshihiro
Published: November 2005

The 0.839eV C-related intracenter luminescence has been investigated using various kinds of Cr-doped and Cr-diffused GaAs. It has been found that the luminescence intensity increases monotonously with the Cr content involved in GaAs but is not linear to the Cr content. This result suggests that the luminescence arises from a complex involving Cr and another defect or impurity. The spectral shape of luminescence is independent of the majority donor impurities contained in GaAs, but the intensity decreases with increase of arsenic pressure during the Cr diffusion. These results indicated that the Cr-related luminescence line at 0.839eV in GaAs: Cr is associated with a complex of Cr and As-vacancy.
Study of Double Foil Acceleration by Intense Relativistic Electron Beam Irradiation
Authors: Higaki Satoshi , Imasaki Kazuo , Miyamoto Shuji , Ozaki Testu , Yabe Takashi , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

The dynamic behavior of double foil target irradiated by an intense relativistic electron beam was measured by optical shadowgraphy. The velocity ratios V
2/V
1 in the collision of two foils were measured and compared with computational analysis. The inelastic factor α obtained from double foil target experiments was in agreement with the inelastic collision model.
Molecular Beam Epitaxy of In0.2Ga0.8Sb
Authors: Gotoh Hideki , Yamamoto Tohru , Kimata Morihiko
Published: November 2005

The MBE growth of In0.2Ga0.8Sb is examined. Undoped films show p-type conduction. Sulfur doped n-type In0.2Ga0.8Sb with H2S gas, which has a mobility of 3000–3500 cm2/V·sec, is obtained. The value is slightly lower than that of bulk In0.2Ga0.8Sb. This may be caused by lattice mismatch between GaAs substrate and In0.2Ga0.8Sb film. N-type In0.2Ga0.8Sb has two donor levels. The deeper one is associated with sulfur, and the other shallow one is similar to the donor level in undoped MBE InSb.
Theoretical Calculation of Normally-Off GaAs MESFET Characteristics Including Effects of Surface Depletion Layer
Authors: Hariu Takashi
Published: November 2005

A theoretical analysis of the normally-off GaAs MESFET is presented, including the effects of a free-surface depletion layer between source and gate as well as between gate and drain. The calculated current-voltage characteristics are in satisfactory agreement with experimental results. The effects of recess depth, fluctuations in the thickness of the active layer and other device parameters are assessed quantitatively.
Preparation of Amorphous GdCo Films with Large Area Uniformity and Stability of Written Bits
Authors: Kobayashi Kikuo , Togami Yuji
Published: November 2005

Double layer films of rf-sputtered amorphous GdCo have been made under different sputtering conditions. The first layer was sputtered with a dc bias voltage, and the second was successively deposited onto the first layer with non-bias. Double layer GdCo film holds as large area uniformity of magnetic properties as bias sputtered film and has good stability of bits as small as 1 µm in diameter. The films with various values of coercive force were also made by changing the ratio of thickness of these two layers. The thermomagnetic recording was carried out at a speed of 1800 rpm on this double layer GdCo disk of 150 mm in diameter.
Interfacial Phenomena in Vacuum-Deposited Metal Films on Silicon Substrate
Authors: Yoon Ki Hyun
Published: November 2005

Pure nickel and gold thin films were vacuum-deposited on (111) silicon single crystals. When Ni/Au/Si samples were heated to about 550°C in vacuum, crystallites of NiSi2 were formed on the silicon substrates. The silicon substrate doped with antimony showed stacking faults, while the silicon substrate doped with phosphorus did not show stacking faults.
Spherulite Growth in GaSe Films
Authors: Hashimoto Hidenori , Suzuki Hiromichi
Published: November 2005

Thin film spherulites were crystallized by heating above 370°C in vacuum from the amorphous GaSe films prepared by flash evaporation. The spherulites are a sort of polycrystalline GaSe and the c-axes are formed finely along the radial direction of the spherulites. Activation energies of crystallization depended on film thickness of the spherulites and were 0.79 eV for 200 nm and 0.32 eV for 550 nm film thickness.
Non-Destructive Determination of Cr Concentration Distribution in Cr Doped Semi-Insulating GaAs Substrates
Authors: Shimizu Haruhito , Ohno Hideo , Hasegawa Hideki
Published: November 2005

Non-destructive determination of Cr concentration distribution in Cr doped semi-insulating GaAs substrates is described. Substrate conductance change Δ
G caused by light illumination, which is known to be correlated with the Cr concentration in the substrate, is determined by the use of a microwave technique. The Cr concentration distribution in semi-insulating GaAs substrates determined by the present method agrees with the tendency expected from the crystal growth condition. The present method would be very useful for ion implantation used in GaAs IC fabrication.
Ablative Acceleration of Thin Foil Targets by Intense Proton Beams
Authors: Miyamoto Shuji , Ozaki Tetsu , Imasaki Kazuo , Higaki Satoshi , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

A focused proton beam of up to 2×1010 W/cm2 was obtained using a pinch-reflex ion diode connected to a Reiden IV generator. Experiments on beam target interaction have been carried out using thin foil targets. In this power range the interaction was explained classically. The experimental dependence of ablation pressure on proton beam intensity was obtained as P
a=3×10-3
I
0.7 bar (I in W/cm2).
Thermoluminescence and Thermally Stimulated Exoelectron Emission from Evaporated LiF and CaF2 Films
Authors: Aoki Masayoshi , Nishikawa Tsuguo , Okabe Shigeru
Published: November 2005

It was found that thin films evaporated onto a substrate in vacuum exhibit both thermoluminescence (TL) and thermally stimulated exoelectron emission (TSEE) when they are heated without any stimulative pre-treatment. These phenomena were observed only once after evaporation, and succeeding repeated heating showed neither TL nor TSEE. The heating rates used were 0.5°C/s for TL and 1°C/s for TSEE. In this study, the temperature at the main glow peak of TL or TSEE from the unirradiated films was found to be higher than that from these irradiated with gamma-rays.
Loss and TM Mode Gain Suppression in Planar Stripe Diode Lasers with Smooth Lateral Profile
Authors: Pietzsch Joachim , Kamiya Takeshi
Published: November 2005

The loss in planar stripe lasers has been calculated in an exact manner. The energy flow balance of the electromagnetic wave is established by a surface integration of the Poynting vector. TM modes are also included whose mode gain is shown to be greatly reduced compared to TE modes. The dependence of the loss coefficient on parameters such as gain width, guiding parameter, absorption coefficient and cavity length were calculated based on a cosh-2 (x)-model of the local gain distribution. The loss increases rapidly in the antiguiding regime and is also very sensitive to the gain width. It is pointed out that the loss coefficient depends on the cavity length, especially for short cavities. Hence it is necessary to revise the conventional technique of determining the internal quantum efficiency and loss coefficient.
The gain width is used as the primary parameter characterizing lateral waveguiding. In addition, a rough estimate is given to relate the gain width to the actual stripe width.
Magnetic-Field-Free Objective Lens around a Specimen for Observing Fine Structure of Ferromagnetic Materials in a Transmission Electron Microscope
Authors: Tsuno Katsushige , Taoka Tadami
Published: November 2005

In order to observe the fine structures of ferromagnetic materials or to observe their magnetic domain structures, special magnetic-field-free lenses in which specimens are set in the upper pole-piece have been developed. In these objective lenses, the spherical aberration depends largely on the shape of the lens, especially, (1) the distance between the positions of the specimen and the peak of the lens field, (2) the diameters of the pole-piece bores and the top face of the upper pole-piece, and (3) the gap length. In a lens with a pole-piece of optimum dimensions, the resulting resolution reached 0.7 nm and the leakage field strength was 0.35 mT. Complicated domain structures of ferromagnetic materials could be clearly observed.
Compact Metal-Ion Beam Source Using Thermal Contact Ionizer
Authors: Sakai Yoshiyuki , Katsumata Itsuo , Oshio Takanori
Published: November 2005

A small, compact ion beam source which can function in an external magnetic field has been developed for use with a heavy ion beam probe for plasma diagnostics. The source consists of a thermal contact ionizer with a beam material reservoir and an electrostatic lens system for beam acceleration and focusing. The beam can be modulated by means of a beam-extracting electrode. An alkali or an alkali earth metal ion beam was produced at energies up to 3 keV. The source functioned sufficiently well in a magnetic field up to 2 kG. The operating parameters for Cs+ and Ba+ ion beams were investigated in detail. A beam current up to 10 µA and a small diameter of 1 mm at the focusing point were obtained.
Experimental Studies on Reflection Spectra in Monodomain Cholesteric Liquid Crystal Cells: Total Reflection, Subsidiary Oscillation and Its Beat or Swell Structure
Authors: Takezoe Hideo , Ouchi Yukio , Hara Masahiko , Fukuda Atsuo , Kuze Eiichi
Published: November 2005

Many optical properties are presented here in the reflection spectra for monodomain cholesterics of various cell thicknesses at various angles of incidence. It is reported for the first time that left-circularly polarized light incident on a left-handed helix gives rise to a beat structure in the subsidiary oscillation, while right-circularly polarized light causes a swell to be superimposed on the subsidiary oscillation. The beat structure is ascribed to the excitation of two sets of optical eigen modes, each set consisting of two optical eigen modes of slightly different wavelength. The polarization characteristics of the total reflection band as well as the selective reflection band are also discussed.
Penetration Depth of Diffusion-Induced Dislocations
Authors: Itoh Nobuo , Nakau Tanehiro
Published: November 2005

To estimate the penetration depth of diffusion-induced dislocations, the depth of the neutral plane of internal stress is obtained quantitatively in values relative to the junction depth of the usual diffusion profiles. The following two cases are considered: (1) the stress distribution is due mainly to the distribution of impurity atoms and (2) the stress is relieved by the generation of a majority of dislocations. The shallow penetration of (1/3–2/3)X
j observed so far is explained by case (1). Deep penetration beyond the junction is shown to be generally possible only in case (2) and at this time, the change of the depth of the neutral plane depends on the moment of the dislocation distribution. It is also explained that the force on a dislocation due to the diffusion-induced stress causes the climbing motion.
Effect of Mn Doping on the Dielectric Properties of Ba2Ti9O20 Ceramics at Microwave Frequency
Authors: Nomura Shoichiro , Tomaya Keiichiro , Kaneta Kumiko
Published: November 2005

The effect of Mn doping on the dielectric properties of Ba2Ti9O20 ceramics has been investigated at microwave frequency. The dielectric constant and the temperature coefficient are not sensitive to the addition of Mn, while the unloaded Q depends strongly upon it as well as on heat treatment at high temperature. A minute addition of Mn leads to an increase in the Q value. A high value of Q of more than 5200 was obtained at 9 GHz with the addition of 0.5∼1.0 mol% Mn.
Raman Spectra of Rhombohedral and α-Monoclinic Selenium under High Hydrostatic Pressure
Authors: Nagata Kiyofumi , Ishikawa Takatoshi , Miyamoto Yasuhiko
Published: November 2005

The Raman spectra of rhombohedral, α-monoclinic, and trigonal selenium have been measured under high hydrostatic pressures up to about 8 kbar at room temperature. The frequencies of the A1-type stretching modes in both rhombohedral and α-monoclinic selenium have been observed to decrease with increasing pressure, as has that of trigonal selenium. This indicates that interference between inter- and intramolecular bondings also exists in crystals composed of ring molecules such as Se6 or Se8.
Green Electroluminescence in Low-Voltage-Driven Metal-Insulator-Semiconductor Structure Devices
Authors: Ohwaki Junichi , Kozawaguchi Haruki , Tsujiyama Bunjiro
Published: November 2005

Changes in emission waveforms and brightness with variations in emitting or insulating film thickness have been investigated in Metal-Insulator-Semiconductor (MIS) structure thin-film electroluminescent (TFEL) devices, such as Glass/In2O3/ZnS:TbF3/Sm2O3/Al. It is found that the decrease in brightness with decreasing ZnS layer thickness can be compensated by an increase in brightness obtained by reducing the insulator thickness, and the emission intensity ratio with regard to the applied voltage polarity (P
(Al-)/P
(Al+)) is proportional to the film thickness ratio of the emitter and the insulator (d
Z/d
I), in MIS-TFEL devices. Under the optimal condition d
Z/d
I=1∼2, when P
(Al-)≃P
(Al+), bright green electroluminescence of 400 fL and 830 fL with threshold voltages of 37 V and 57 V, respectively, are obtained under 5 kHz sinusoidal voltage excitation.
Point Defect Clusters at a Twin Boundary in Pure Aluminum
Authors: Yamakawa Kohji , Oda Hiroyuki , Shimomura Yoshiharu
Published: November 2005

Point defect clusters at a twin boundary in pure aluminum are observed by transmission electron microscopy. At the coherent twin boundary, characteristic triangular loops of the vacancy type are formed in quenched specimens, while loops of the interstitial type are formed in electron-irradiated specimens. The direction of the triangles of the vacancy loops is opposite to those of the interstitial loops. These facts can be explained as arising from the difference in the atomic arrangement of the second nearest-neighbor layers around the dislocation loops. It can be concluded that whenever a faulted loop is formed on a stacking fault, the loop is triangular.
During electron irradiation of a boundary which contains a vacancy loop, the vacancy loop grows or shrinks depending on the environment around it, while an interstitial loop always grows.
Non-Equilibrium Thermodynamics and Energy Distribution Function of Neutron Gas in Constant Power Reactor under Coupling of Neutrons and Medium
Authors: Hayasaka Hideo
Published: November 2005

The thermodynamics and the energy distribution function of the neutron gas in a constant power reactor are considered, taking into account the burn-up of fuel. To separate the secular motion of neutrons owing to fuel burn-up and the microscopic fluctuations of neutrons around this motion, a long time of the order of several months is divided into m equal intervals, and the respective states corresponding to m small time intervals are treated as quasi-stationary states. The local energy distribution function of the neutron gas in the quasi-stationary state is given by a generalized Boltzmann distribution specified by the respective generalized activity coefficient for each subsystem. The effects of fuel burn-up on the respective distribution functions for successive small time intervals are taken into account through various quantities relating to reactor physics, depending upon the fuel burn-up, by successive approximation.
Josephson Single-Input Self-Gating and Circuits
Authors: Nakanishi Takuji , Hohkawa Kohji , Ishida Akira
Published: November 2005

Two new types of Josephson Single-Input Self-Gating And (SGA) circuit were densigned, fabricated and tested. The circuits consist of three Josephson junction interferometers or RCL (Resistor Coupled Logic) gates and single junctions. The operation test results show that the SGAs operte correctly in latching data for a necessary time duration with fairly wide operating margins.
A Simple Method for Single-Frequency Operation and Amplitude- and Frequency-Stabilization of an Internal-Mirror He–Ne Laser
Authors: Sasaki Akira
Published: November 2005

This paper describes a new and simple method for obtaining the amplitude- and frequency-stabilized single mode output of an internal-mirror He–Ne laser (λ=633 nm). The laser tube is cooled with a constant-speed fan and the electric current signal which is proportional to the total back beam intensity is detected with a silicon photodiode and is applied to an electric heater which controls the laser tube length change due to thermal contraction. Consequently, the laser amplitude and frequency are stabilized at the same time. A relative amplitude stability of ±0.16% and relative frequency stability of ±9×10-9 are obtained over a period of 10 minutes or longer.
Lattice Bending in LEC-Grown Semi-Insulating GaAs Wafers
Authors: Yasuami Shigeru , Mikami Hitoshi , Hojo Akimichi
Published: November 2005

Lattice bending in LEC-grown semi-insulating GaAs crystal wafers was investigated by X-ray diffraction. Various distributions in the lattice bending were observed in wafers from different boules. Prominent bends, with radii of curvature of about 20 m, were observed at places where the relevant topographs showed the presence of fine cellular dislocation networks. The apparent wafer bending was also examined optically and was found to be caused mainly by back surface damage.
Electrical and Optical Properties of p · ZnSnAs2/n·ZnSe Heterodiode
Authors: Takenoshita Hiroshi , Nakau Tanehiro
Published: November 2005

A p·ZnSnAs2/n·ZnSe heterodiode was prepared by LPE from Sn solution on a low-resistivity n·ZnSe substrate. The I-V characteristics of the diode were measured, and it was found to have a good rectification ratio of 104 at 1 V. The diode showed a photoresponse extending over a wide wavelength region between 0.4 and 1.9 µm. The measurements of the C-V characteristics showed that the diode had an abrupt junction with a diffusion potential of 0.60 V. The dielectric constant for ZnSnAs2 was first estimated from the analysis of the C-V characteristics: ε

A
=12.0ε
0. The values of the minority carrier lifetime were obtained from the decay curves of EBIC as 70 ns and 0.4 ns for n·ZnSe and p·ZnSnAs2, respectively.
Travelling Waves on a Josephson Transmission Line
Authors: Tateno Hiroshi , Sakai Shigeki
Published: November 2005

Various properties of stationary travelling waves propagating along a Josephson transmission line having positive nonlinear differential tunnelling conductance and distributed bias current are discussed geometrically in the state plane. First, the change of patterns of solutions in the state plane is uniquely determined for changes in conductance, fluxon velocity and bias current. Second, it is demonstrated that for the linear component of the conductance only, an event takes place in which the solitary wave velocity does not reach the velocity of the electromagnetic waves on a dissipationless transmission line in the certain limit of bias current. Finally, it is shown numerically that the non-linearity of the conductance has important effects on the waves, both quantitatively and qualitatively.
Radiation Effect in Hexatriacontane Thin Film
Authors: Ueno Nobuo , Sugita Kazuyuki , Koga Osamu , Suzuki Shin
Published: November 2005

The secondary electron emission spectra of hexatriacontane thin film were measured as a function of irradiation time with an electron beam of about 19 eV. The spectral features which originate in the conduction band features in the crystalline state shifted to the low kinetic energy side linearly with the logarithm of the irradiation time. The shift is explained as an increase in the electron affinity due to the decomposition of hexatriacontane molecules.
Formation and Properties of Plasma-Polymerized Carbon Disulfide Films
Authors: Asano Yoshihiro
Published: November 2005

Thin polymer films were prepared by the rf glow discharge polymerization of carbon disulfide (CS2) monomer gas. The film structure, thermal properties, optical properties and photoconductivity were studied in order to establish the characteristics of the CS2 films. The film composition was found to depend strongly on the polymerization conditions, and ranged from CS0.16 to CS14. A film with high sulfur content sublimated at low temperature, while that with low sulfur content exhibited good photoconductivity. These characteristics are similar to those of chalcogenide glasses rather than other plasma polymers.
A Laser Technique for State-Selected Time-of-Flight Analysis by Pseudo-Random Modulation
Authors: Baba Hiroshi , Horiguchi Hiroyuki , Kondo Masamichi , Sakurai Katsumi , Tsuchiya Soji
Published: November 2005

A laser technique has been developed for the time-of-flight (TOF) analysis of state-selected atomic or molecular beams. The technique was applied to TOF measurements of Na atoms seeded in supersonic rare gas beams. When a dye Baser excited Na atoms in one of the hyperfine levels of the 32S1/2 state, this level was completely depopulated as a result of the optical pumping effect. This depopulation could be detected at a downstream position by the same Baser light, since the optically-pumped atoms were transparent, and thus the TOF spectrum could be derived by taking the time correlation between the pseudo-randomly modulated pump laser light and the depopulation detected by LIF. A preliminary scattering experiment of Na by CO2 and SF6 was carried out to confirm the effectiveness of this method.
Changes in Electrical Resistance and Auger Electron Appearance Potential Spectra of Titanium Thin Films by Oxygen Diffusion
Authors: Konishi Ryōsuke , Sasaki Hajime , Kato Susumu
Published: November 2005

The electrical resistances of titanium evaporated films with a thickness of about 100 Å were measured after exposure to oxygen. Increases in the resistance up to an oxygen exposure of 10L follow a nearly straight line, but the increases become smaller as the Tempax glass (borosilicate glass) substrate temperature during titanium evaporation rises. This is thought to be caused by the difference in grain size of the films. A diffusion model of the phenomena is given. Auger electron appearance potential spectra, which give information about chemical bondings, show no evidence of the existence of any stable compounds in the films.
Mode Switching in Injection Lasers Induced by Temperature Variation and Optical Feedback
Authors: Ogasawara Nagaatsu , Ito Ryoichi , Kato Masahiro , Takahashi Yoshitaka
Published: November 2005

Effects of optical feedback and temperature fluctuation on the longitudinal mode behavior of an AlGaAs injection laser have been studied utilizing the transient temperature variation produced by pulsed current excitation. Small temperature fluctuations (∼0.01 K for a feedback distance of about 300 mm) induce mode switching at relatively low power levels (1∼4 mW). This behavior is shown to be consistent with the compound cavity model and the gain suppression effect associated with the inhomogeneity of the gain spectrum. It has also been found that mode switching is always accompanied by a change in the output power, indicating that this phenomenon is an important source of excess optical noise.
Multi-Channel Mass-Separated Neutral Particle Energy Analyser for Simultaneous Measurements of Hydrogen and Deuterium Atoms Emitted from Tokamak Plasma
Authors: Takeuchi Hiroshi , Matsuda Toshiaki , Miura Yukitoshi , Shiho Makoto , Maeda Hikosuke , Hashimoto Kiyoshi , Hayashi Kazuo
Published: November 2005

A mass-separated neutral particle energy analyser able to carry out the simultaneous measurement of hydrogen and deuterium atoms emitted from a tokamak plasma was constructed. The analyser was calibrated for the energy and mass separation in the energy range from 0.4 keV to 9 keV. It was installed in the JFT-2 tokamak in order to investigate the behavior of deuterons and protons in a JFT-2 tokamak plasma heated by ion cyclotron wave and neutral beam injection. It was found that the energy spectrum could be determined with sufficient accuracy, and the ion temperature obtained from the energy spectrum was in good agreement with the ion temperature deduced from the Doppler broadening of the impurity ion line.
Effect of Nonuniformity of Anode Plasma on Focal Spot Size of Pulsed Ion Beams Extracted from a Reflex Triode
Authors: Kitamura Akira , Yano Syukuro
Published: November 2005

A pulsed ion beam was extracted from a curved reflex triode without axial magnetic field and was focused ballistically onto a spot. Since the observed time-dependent focal spot size did not fit the value predicted by calculations taking into account the space charge or the current of the beam itself, it was hypothesized that the beam divergence is due to the nonuniformity of the anode plasma. To check this hypothesis, the nonuniformity of the anode plasma was measured by using the light emitted from the anode. The beam divergence under the influence of this nonuniform anode plasma was calculated, giving a focal spot size in fairly good agreement with the observed one.
Quantitative Analysis of Etching Rate Profiles for 11B+-Implanted Si3N4 Film
Authors: Nakata Jyoji , Kajiyama Kenji
Published: November 2005

Etching rate enhancement for 11B+-implanted Si3N4 film was investigated both experimentally and theoretically. The etching solution was concentrated H3PO4 at ∼165°C. Film thicknesses were precisely measured by ellipsometry.
Enhancement resulted from Si-N bond breaking. This was confirmed by a decrease of infrared absorption at a 12.0 µm wavelength for Si-N bond vibration. Main and additional peaks were observed in the etching rate profile. The former was due to nuclear damage and was well represented by the calculated etching rate profile deduced from the nuclear deposited energy density distribution. The latter existed in the surface region only when the ion projected range was shorter than the film thickness. This peak was possibly caused by charge accumulation in the insulating Si3N4 film during 11B+ implantation.
Growth of NH4Cl Single Crystal from Vapor Phase in Vertical Furnace
Authors: Nigara Yutaka , Yoshizawa Masahito , Fujimura Tadao
Published: November 2005

A pure and internally stress-free single crystal of NH4Cl was grown successfully from the vapor phase. The crystal measured 1.6 cmφ×2 cm and had the disordered CsCl structure, which was stable below 184°C. The crystal was grown in an ampoule in a vertical furnace, in which the vapor was efficiently transported both by diffusion and convection. In line with the growth mechanism of a single crystal, the temperature fluctuation (°C/min) on the growth interface was kept smaller than the product of the temperature gradient (°C/cm) and the growth rate (cm/min). The specific heat of the crystal was measured around -31°C (242 K) during cooling and heating cycles by AC calorimetry. The thermal hysteresis (0.4 K) obtained here was smaller than that (0.89 K) of an NH4Cl crystal grown from its aqueous solution with urea added as a habit modifier.