bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of Position Control System in JIPP T-II
Authors: Sakurai Keiichi , Tanahashi Shyugo
Published: November 2005

Computations and experiments on the stability of a feedback control system for maintaining a plasma column in equilibrium are described. The time response of the displacement of the plasma to the desired position is examined by solving the equation of motion of the plasma column. We show that the stability of the feedback control system is improved by using an additional term which represents the shift velocity of the plasma column.
Superconductive Transition Point of Tantalum and Niobium as a Reference Temperature
Authors: Inaba Akira
Published: November 2005

The applicability of the superconductive transition point of Ta and Nb for use as a temperature reference point was examined. An unusual impurity effect was found in both metals; In a plot of the transition temperature (Tc) vs. the inverse resistance ratio (1/Γ), a substitutional impurity had a larger reducing effect onTcthan an interstitial impurity. The purest specimens we obtained, with Γ=5000 for Ta and Γ=4500 for Nb, were prepared by zone-melting and subsequent annealing just below the melting points under ultra-high vacuum. From theirTcvalues and analyses of the impurity effect, theTcvalues of impurity-free Ta and Nb were determined as 4.4924 K and 9.2877 K, respectively, based on the 1976 Provisional 0.5 K to 30 K Temperature Scale, the currently-accepted temperature standard.
Amorphous GaAs Films by Molecular Beam Deposition
Authors: Matsumoto Nobuo , Kumabe Kenji
Published: November 2005

Amorphous GaAs films are prepared by molecular beam deposition. The dependence of the film structure and composition on the preparation conditions is studied. By setting the substrate temperature just below the crystallization temperature, near-stoichiometric amorphous films are obtained with As-rich molecular beams. The electrical and optical properties of the films are summarized in terms of the composition ratio. The results imply the existence of stoichiometric amorphous GaAs films and the possibility of controlling their conduction type.
Origin of Si(LMM) Auger Electron Emission from Silicon and Si-Alloys by keV Ar+ Ion Bombardment
Authors: Iwami Motohiro , Kim Su Chol , Kataoka Yoshihide , Imura Takeshi , Hiraki Akio , Fujimoto Fuminori
Published: November 2005

Si(LMM) Auger electrons emitted from specimens of pure silicon and several Si-alloys (Ni-Si, Pd-Si and Cu-Si) under keV Ar+ ion bombardment, were examined. In the Auger spectra from all specimens studied there were four peaks at energies of 92, 86, 76 and 66 eV. The Auger signal intensity varied considerably with both the incident angle and the energy of the primary ion beam. It is proposed that the Auger electrons are emitted from silicon atoms (or ions) just beneath the specimen surface but free from the bulk network.
Identification of Photochromic Absorption in KTaO3 Doped with Ni and Fe
Authors: Akishige Yukikuni , Ohi Kikuo
Published: November 2005

The photochromic properties of KTaO3 doped with Ni and Fe are studied using optical and electron spin resonance techniques, and the centers responsible for the photochromic absorption bands are identified. The absorption band at 630 nm is due to electron transfer from the Ni3+-V0-2e center to the conduction band. Two bands near 450 nm and 520 nm are due to electron transfer from the valence band to Fe4+ and Fe5+ centers. The photocurrent is enhanced by Ni doping but is quenched by Fe doping, and it is found that the Ni3+-V0-e center acts as an electron trap, while Fe3+ acts as a hole trap.
Second Harmonic Generation of Epitaxially-Grown GaN Crystal
Authors: Ishidate Takeo , Inoue Kuon , Aoki Masaharu
Published: November 2005

The magnitudes of the SHG coefficients, d
31, d
33 and d
15 of GaN and the relative sign of d
31 and d
33 have been measured, using an epitaxially-grown crystal sample. The observed values of d
31/d
33 and d
15/d
33 were -0.48 and -0.58, respectively, and |d
33|=88×|d
11(quartz)|. The reliability of the Maker fringe technique in SHG measurement for an epitaxially-grown sample as thin as 30 µm is discussed from the experimental point of view.
Cathodoluminescence Saturation and Decay Characteristics of ZnS: Cu,Al Phosphor
Authors: Kuboniwa Shigeo , Kawai Hiroji , Hoshina Teruhiko
Published: November 2005

An attempt at a qualitative understanding of the luminescence saturation mechanisms of ZnS: Cu, Al phosphor has been made by studying the exicitation current-density dependences of the luminescence efficiencies and decays at several activator concentrations, temperatures and accelerating voltages. The saturation behavior is independent of the Cu and Al concentrations in the region >10-4 g·atom/mol-ZnS. Neither the temperature nor the accelerating voltage affects the saturation. Nonradiative deactivation of the luminescent centers occurs in the early stages of the decay. Auger recombination involving a donor-acceptor pair is postulated as the nonradiative process responsible for the saturation.
Low-Frequency Photocurrent Oscillations in CdIn2S4 Single Crystals
Authors: Seki Yasukazu , Endo Saburo , Irie Taizo
Published: November 2005

Low-frequency photocurrent oscillations in CdIn2S4 single crystals when a high electric field is applied at low temperature have been studied through simultaneous observations of the photocurrent and the photoluminescence. Several parameters necessary for analysis of the oscillations have been determined from additional experiments. We found that the pulse-type oscillations disappeared when light of photon energies between 1.97 and 2.54 eV was superposed. The distribution of the electric field in the sample was measured and it was found tbat the region of high electric field, the so-called domain, does not move in space but that the electric field varies periodically, leading to the current oscillation. The mechanism of the pulse-type photocurrent oscillations in CdIn2S4 single crystals is well-explained by the three-center model considering the thermal quenching process.
Use of a Hollow Cathode in a DuoPIGatron Hydrogen Ion Source
Authors: Tanaka Shigeru , Morita Hiroaki , Sakuraba Junji
Published: November 2005

Hollow cathode arc discharges in hydrogen gas were studied experimentally. An impregnated tungsten emitter or an oxide-coated nickel emitter of 1 cm i.d. and 2 cm long was used as the hollow cathode. When the hollow cathode was positioned opposite a plain anode, the discharge-sustaining voltage became 40 to 60 volts with a gas flowrate greater than 1 Torr·1/s which corresponds to a gas pressure of 13 m Torr in the discharge chamber. When it was used in a duoPIGatron ion source, the discharge voltage varied from 80 to 120 volts depending upon the gas flowrate and the source magnetic field strength. Beam extraction from the ion source was carried out and hydrogen ions of 3 A at 25 keV were extracted.
Fast Compressional Alfvén Waves in a Tokamak
Authors: Takahashi Hironori
Published: November 2005

Enhancement of cyclotron damping is theoretically evaluated based upon the wave E-field polarization which is modified by the two-ion hybrid resonance. The degree of enhancement and its asymmetry about the plasma center is consistent with experimental observations. The enhancement factor is very large at low plasma densities at which most of the past damping strength measurements have been reported, but approaches unity at high densities. This implies the pre-dominance of pure cyclotron damping in future reactor-like deuterium plasmas in spite of the presence of minority protons. A simple antenna and a pair of limiters are sufficient to couple rf power with an overall power deposition efficiency of about 75%. There is no evidence that parasitic loading accounts for a significant amount of the power.
Metal Impurity Injection into DIVA Plasma with a Q-Switched Laser Beam
Authors: Yamauchi Toshihiko , Nagami Masayuki , Sengoku Seio
Published: November 2005

The impurity blow-off technique is a useful technique for obtaining clear evidence of impurity behaviour in Tokamak plasmas. In this paper, we describe how the blow-off technique is applied to a DIVA plasma and present some experimental results. The metals injected are aluminium and gold. A layer of metal about 0.2 µm thick is adsorbed onto a pyrex glass plate, through which a Q-switched laser beam passes to irradiate the thin film. The film is vaporized by the laser beam and injected into the DIVA plasma with directional velocity. The injection rate is easily and accurately controlled by changing the film thickness and/or the aperture of the laser beam.
The total number of aluminium atoms evaporated is 8.0×1016 and their velocity is 5.2×105 cm/s. Thus, the maximum increase in electron density is about 8% and the spectral line signals of Al XI 550 Å are observed with good reproducibility.
Microprocessor-Controlled Multi-Channel High-Voltage Regulator System
Authors: Imori Masatosi , Shibata Itsuo , Shimokoshi Fumio
Published: November 2005

A multi-channel high-voltage regulator system has been developed, in which each channel supplies a photomultiplier with an independently regulated high voltage. A regulator in the channel produces a regulated output high voltage from a common unregulated high voltage power supply. In the regulator, an opto-coupler is used through which an error amplifier drives a pass transistor. The output high voltage of the channel is adjusted through a 12-bit digital to analog convertor which is made of CMOS digital IC's. A microprocessor is incorporated in the system to keep the individual output high voltages within permissible deviation through digital feedback.
Melting and Solid-Solid Transition of Polyethylene under Pressure
Authors: Hikosaka Masamichi , Minomura Shigeru , Seto Tsuneo
Published: November 2005

The thermal behaviours of unfractionated polyethylene (PE) was observed up to 31.4 kb by differential thermal analysis, and its pressure-temperature phase diagram was obtained. The thermograms showed three signals, denoted I, II and III. Signal I, the melting of folded chain crystal, was observed up to 8 kb. Below 4 kb, signal II corresponded to the melting of orthorhombic solid; between 4∼8 kb, it corresponded to the superposition of the melting of orthorhombic solid and orthorhombic-hexagonal transition; and above 8 kb, it corresponded to the orthorhombic-hexagonal transition alone. Above 4 kb, signal III had a newly-observed flat shape for a specimen crystallized at elevated pressure, but a peak shape for a specimen crystallized at 1 b. The flat signal corresponded to the continuous melting of hexagonal solid. The effect of the molecular weight distribution which makes PE behave as a multi-component system at high pressure is discussed.
Accurate Determination of a Low-Order Fourier Coefficient of the Potential of Aluminium Single Crystals by a Modified Thickness Fringe Method
Authors: Kuwabara Shigeya , Uefuji Tateki , Inokuchi Masayuki
Published: November 2005

A modified thickness fringe method is proposed for the determination of a low-order Fourier coefficient of the crystal potential. This method can be applied not only to single crystals with perfect wedge shape but also to those with some irregularities by introducing a `surface function', which can automatically correct the irregularity of the fringe periods due to the wedge surfaces. Electro-thinned aluminium single crystals are used as a reference substance in experiments with and without a filter technique. Comparison of the experimental data with n-slice calculations can give the coefficient with an error of less than 1 percent.
The Climbing Motion of Faulted Dislocation Loops Induced by Elastic Interaction
Authors: Haruyama Osami , Kawamoto Hiroshi , Yamaguchi Hiroyuki , Yoshida Sho
Published: November 2005

The movement of faulted dislocation loops during annealing has been studied with transmission electron microscopy using the usual stereotechnique. It is revealed that the distance between two nearby faulted dislocation loops in a thin foil varies during annealing at 95°C for 2 hours without their sizes changing. This variation in distance is considered to occur by pipe diffusion due to the elastic interaction between the loops. The vacancy concentration and the vacancy flow along the perimeter of the loops are calculated by considering the interaction force between their segments. It is shown that the vacancy flow that moves loops exists when the distance between loops is less than 200 Å. The activation energy for pipe diffusion is estimated to be about 0.90 eV.
The Effects of Repeated Electron Irradiation for the Formation of Interstitial Loops in Pure Aluminum
Authors: Tanaka Kunihiro , Shimomura Yoshiharu
Published: November 2005

In an electron microscope, pure aluminum foil was irradiated at 120°C with 200 keV electrons to form interstitial loops and then heated at 200°C to anneal them out. When such a process was repeated many times on the same position of a specimen, the number density of interstitial loops (I-loops) decreased with increasing number of repeats. In a specimen whose number density of I-loops had already decreased greatly by repeated irradiation at l20°C, the relation between the number density of I-loops and the irradiation temperature was examined from -160°C to 120°C. Above 0°C, the number density of I-loops was smaller than that of a freshly irradiated specimen. Below 0°C, it was the same as that of a freshly irradiated specimen. These results are interpreted as meaning that an I-loop nucleates at an impurity cluster above 0°C, whereas it does so at a single impurity below 0°C.
Control of Solid Phase Epitaxial Growth in the Pd-Si System by Carbon Ion Implantation
Authors: Ishiwara Hiroshi , Saitoh Shuichi , Furukawa Seijiro
Published: November 2005

It has been demonstrated that a solid phase epitaxial growth in the Si(100)/Pd/Si(amorphous) system can be controlled by C+ ions introduced by the implantation technique. These were implanted into Pd or St(a) films at energies ranging from 50 to 160 keV after film deposition. The implantation doses were adjusted so that the maximum concentration of C+ ions ranged from 0.25 to 4 at. %. The growth behavior was measured by the MeV He+ Rutherford backscattering and channeling techniques. The results show that Pd atoms in the film move towards the surface and they are concentrated near the average projected range of C+ ions in the Si(a) film. They also show the radiation damage produced by the implantation does not affect these phenomena. The optimum conditions for obtaining the best epitaxial layer have been investigated with regard to parameters such as film thickness, ion species, implantation dose and energy, annealing time and temperature, and so on. The best epitaxial layer was obtained when C+ ions were implanted near the interface between the Si(a) and Pd films, though the layer still contained residual Pd atoms of 1 to 2 at. %.
Reduction of Metal Oxides by Electron Cyclotron Resonance (ECR) Plasma of Hydrogen–A Model Study on Discharge Cleaning
Authors: Sakamoto Yuichi , Ishibe Yukio
Published: November 2005

A reduction experiment on oxides of Cu, Ni, Fe, Mo and Ti was carried out, using a low electron temperature ECR plasma of hydrogen. Reduction rates of these oxides were estimated by observing the disappearance of interference rings of oxide layers. The reduction efficiency η of H+ flux was evaluated; η=0.4 for copper oxide and 10-3<η<10-2 for other oxides.
Roughly, the reduction rate decreased with an increase in the metal-oxygen binding energy.
It was shown that oxide layers with a thickness in the order of magnitude 10-1 µm were reduced without difficulty. It is of interest from the viewpoint of discharge cleaning of fusion-oriented machines.
X-Ray-Induced Thermally-Stimulated Currents in Polyvinylidene Fluoride
Authors: Suzuoki Yasuo , Mizutani Teruyoshi , Shimozato Masao , Sugiura Nobuaki , Ieda Masayuki
Published: November 2005

Thermally-stimulated currents (TSC) induced by a prior X-irradiation in polyvinylidene fluoride (PVDF) were observed and the nature of carrier traps was discussed. PVDF shows three split TSC peaks, the P1, P2 and P3 peaks in ascending order of temperature. Both P1 and P2 peaks are due to dipole orientation in amorphous regions associated with the γ- and β-relaxations, respectively. The P3 peak is due to carrier traps in the regions related to the α-type PVDF crystallites. The field dependence of the TSC revealed that at least two kinds of carrier traps are responsible for the P3 peak. The dependence of the irradiation temperature on TSC, together with the field dependence, suggests that the carrier release from one kind of carrier trap is strongly affected by the electric field.
Statistical Analysis of Dielectric Strength of BaTiO3 Ceramic Films
Authors: Yamashita Kimihiro , Koumoto Kunihito , Takata Masasuke , Yanagida Hiroaki
Published: November 2005

The Weibull function was successfully applied to dielectric strength data of BaTiO3 ceramic films. The degree of scatter in the dielectric strength was evaluated by the Weibull parameter β. The β value was from 6 to 7 for the large-grained specimen. The β values for the small-grained specimen were from 3 to 4. The dielectric strength of the latter specimen was larger than that of the former. For the intermediate specimen, the observed results of the dielectric strength split in two portions on the Weibull chart. The β value of one portion was 6.0 and the other was 3.9. The breakdown of the specimen was assumed to occur by bimodal mechanisms.
Properties of Zn-Doped P-Type In0.53Ga0.47As on InP Substrate
Authors: Takeda Yoshikazu , Kuzuhara Masaaki , Sasaki Akio
Published: November 2005

Zn-doping in In0.53Ga0.47As was investigated. The dependence of the resistivity and Hall mobility of Zn-doped In0.53Ga0.47As upon the hole concentration is found to be the same as that of Zn-doped In0.15Ga0.85As. Photoluminescence in Zn-doped In0.53Ga0.47As is investigated in relation to hole concentration. In0.53Ga0.47As homojunction diodes are made, and minoritycarrier diffusion lengths of holes and electrons are derived from the EBIC (electron beaminduced current) intensity which is dependent upon the distance from the junction interface.
Electrical Resistivity of A-15 Compound V3Sn
Authors: Oota Akio , Yanagida Kazuhiko , Noguchi Seiichiro
Published: November 2005

Normal-state electrical resistivity of an A-15 compound V3Sn with a resistivity ratio of 5.78 and a T
c of 4.10 K is reported as a function of temperature. The low temperature results are fit well with the T
3 law of the Wilson theory. The high temperature results, on the other hand, show a deviation from the linear T law. This deviation cannot be explained by taking into account the actual electronic density of states and the anharmonicity of phonon mode, which are introduced to improve the Wilson theory. The phenomenological expression based on the saturation model is well fitted to the high temperature results.
DC Tunneling Spectroscopy to Determine the Distribution of Interface States
Authors: Takase Yoshihiko , Odajima Akira
Published: November 2005

A method to determine the interface state distribution in an MOS structure with degenerate p-type semiconductor from the dc tunneling current is proposed and applied to metal/SiO2/p++-Si structure. The main feature of the present method is the use of the theory of tunneling developed by Freeman and Dahlke with some modification. The (Au/Ti)/SiO2/p++-Si was prepared by thermal oxidation in wet O2 at 800°C. It has been found that σt
N
ss (σt is the tunneling capture cross-section and N
ss the density of states per unit energy and unit area) varies concavely against the energy over the whole band gap of p++-Si and the interface state distribution obtained by the present method is consistent with that obtained for an MOS structure with thick SiO2 film provided σt is independent of energy. These features are found for both annealed and unannealed samples.
Some Characteristics of a Linear Turbulently Heated Plasma as Observed by a Secondary Emission Detector
Authors: Nagatsu Masaaki , Asada Osamu , Yoshioka Kazuo , Tsukishima Takashige
Published: November 2005

The measurements of the ion temperature T
i are carried out on a turbulently heated plasma, using a secondary emission detector (S.E.D.), and unreasonably high values of T
i are obtained. In order to unfold the observed results, a simulation code is developed, which includes the ionization effects as well as the energy transport equations for electrons and ions. In the calculations, the heating current, heating voltage, and the electron temperature T
e are chosen as independent variables in accord with the experimental conditions. The value of T
i as a function of time is first evaluated. Reasonable agreements are obtained between the calculated and observed temporal behaviors of the S.E.D. output currents. The effect of high energy tail in the ion energy distribution is also examined.
Ballooning β Limit of a Non-Circular Small-Aspect-Ratio Tokamak
Authors: Yamazaki Kozo
Published: November 2005

High mode number ballooning instabilities have been studied to obtain the maximum beta values for the quasi-uniform current equilibrium model (Soloviev).
For circular boundary plasmas, the reduction of the aspect ratio does not lead to the increase of the ballooning mode stable β-value. The critical β is approximately given by 0.03/A{0.25+(1/A)2}, where A is the plasma aspect ratio. For the stability of non-circular cases against high n ideal ballooning modes, the moderate vertical elongation of D-shapes is appropriate for large-aspect-ratio tokamaks, while horizontally elongated inverse-D shapes are favorable for small-aspect-ratio plasmas.
Ultrasonic Study of High Pressure Phase in Polyethylene
Authors: Nagata Kiyofumi , Tagashira Katsuharu , Taki Seiji , Takemura Tetuo
Published: November 2005

Behaviors of transitions and the nature of high pressure phase in polyethylene are studied using methods of longitudinal and transverse ultrasonic waves, differential thermal analysis (DTA) and X-ray diffraction by PSPC X-ray system. Two anomalous absorption peaks of longitudinal wave agree with the normal phase to high pressure phase transition temperature and the high pressure phase to fused phase transition temperature as observed by DTA and X-ray diffraction, respectively. For the folded-chain crystal sample, the recrystallization phenomena by lamella thickening during the heating process has been discovered by the anomaly in longitudinal sound velocity. The result of transverse wave shows that the modulus of rigidity of high pressure phase is of the same order in magnitude as that of the fused state. Therefore, the high pressure phase should be a nematic liquid crystal-like state.
Optical Nutation Echoes in Ruby
Authors: Muramoto Takao , Nakanishi Shunsuke , Tamura Osamu , Hashi Tsuneo
Published: November 2005

We observed the optical nutation echoes, i.e., the optical analog of rotary-spin echoes, in ruby. The experiment was carried out using a Stark switching technique. The inversion of the effective field in the rotating frame was achieved by applying a small short Stark pulse (phase-shifting pulse) whose amplitude ΔE and width Δt satisfy the condition that Δω·Δt is equal to an odd multiple of π where Δω is the frequency offset produced by ΔE. A train of nutation echoes was also observed by applying successive phase-shifting pulses. The observed nutation-echo-envelope decay time was 12 µs which is nearly equal to 2T
2 consistent with the theoretical prediction. Radiation-locking and radiation-locked echo experiments were also performed by using similar phase-shifting techniques.
Estimation of the Cooling Efficiency of HgCr2S4 near 60 K as a Magnetic Refrigerant
Authors: Hashimoto Takasu , Ikegami Tomio , Okada Toshihiro
Published: November 2005

We have measured both the magnetic field dependence of the magnetic moment and the specific heat of HgCr2S4 and have ascertained that HgCr2S4 may be suitable as the refrigerant in magnetic refrigerators near 60 K.
Preparation of Superconducting BaPb1-xBixO3 Thin Films by RF Sputtering
Authors: Suzuki Minoru , Murakami Toshiaki , Inamura Takahiro
Published: November 2005

Superconducting BaPb1-x
Bi
x
O3 thin films were successfully prepared by RF diode sputtering with a relatively high deposition rate of 50–120 Å/min and subsequent heat treatments. Their superconducting transition onsets are about 8 K. It was found that high oxygen partial pressure was a requisite for the preparation of BaPb1-x
Bi
x
O3 thin films. Low oxygen pressure during discharge brings about poor films with coarse surfaces which have semiconducting high resistivity and broad transition.
A Simple and Stable Microwave SQUID
Authors: Kikuchi Yoshiko , Miki Yukinobu , Masumi Taizo
Published: November 2005

A new, simple and stable type of microwave SQUID has been developed successfully at 10 GHz by using a bridge type junction which can be fabricated very easily. In consequence of adopting a junction of this type, the microwave SQUID has the merit of being free from adjustment and endures several heating cycles between room and liquid He temperatures. This type of SQUID has a slightly poorer S/N ratio, to be improved in future, but has the same characteristics as previously reported SQUIDs with a point contact junction.
Time Dependent Fluorescence Spectrum of an e-Beam Pumped KrF Laser Medium in a High Current Density Range
Authors: Hara Hideo , Umezu Nobuhiko , Umezu Kazuko , Takuma Hiroshi , Namba Susumu
Published: November 2005

Parametric dependence of the time dependent fluorescence spectrum of an e-beam pumped KrF laser medium was investigated in a high current density range of 120 to 250 A/cm2. Higher optimum pressure and shorter pulse duration were the prominent features. The results were fitted with a proposed rate equation model, indicating that the high current density e-beam pumping is favorable for high efficiency laser operation mainly because of a great deal of reduction of the three body quenching rate at higher temperature. A possibility of generating 25m J/cm3 of 250 nm photons with an efficiency of 8% was predicted.
Pressure-Induced Resistance and Color Change in KTN
Authors: Okai Bin , Tsukioka Masayuki , Fujita Taketoshi
Published: November 2005

Semiconducting KTa0.7Nb0.3O3, when subjected to a pressure of about 20 kbar at room temperature, changes color from blue to yellow, simultaneously undergoing an increase in electrical resistance by an order or two of magnitude. The change is irreversible; yellow specimens remain unchanged when atmospheric pressure is restored. The structure remains the same, cubic perovskite, throughout the change.
Transmission Electron Microscope Observation of Mechanically Damaged InGaAsP/InP Double-Heterostructure Light-Emitting Diode
Authors: Ueda Osamu , Yamakoshi Shigenobu , Yamaoka Toyoshi
Published: November 2005

An InGaAsP/InP DH LED, whose active region has some mechanical damage, was operated at room temperature and was investigated by EL topography and TEM. An EL pattern of the diode included two “dark-band” defects which lay in the <110> direction. After 100 hours of operation, the EL pattern did not change. TEM observation showed that no glide dislocations were generated from the mechanical damage. This result suggests that dislocation glide motion during carrier injection or optical excitation occurs only with difficulty in InGaAsP/InP DH LED's at room temperature.
Crystallization Process from Amorphous PbTiO3
Authors: Takashige Masaaki , Nakamura Terutaro , Ozawa Haruo , Uno Ryosei , Tsuya Noboru , Arai Ken Ichi
Published: November 2005

Investigation has been made of the crystallization from the rapidly quenched amorphous state of PbTiO3 utilizing DTA and Raman spectroscopy. The DTA curves reveal sharp exothermic peaks between 500 and 600°C on heating the as-quenched samples. Essential differences between the Raman spectra from the as-quenched state and those from the crystalline state have been recognized: the soft mode observed in the crystalline state is found not to exist in the as-quenched state. By annealing samples, a dramatic change in the Raman spectra due to the structural relaxation is clearly visible.
Growth of Fiber Crystals for Infrared Optical Waveguides
Authors: Mimura Yoshinori , Okamura Yasuyuki , Komazawa Yoshihisa , Ota Chuichi
Published: November 2005

Modified floating zone technique is proposed to draw fiber single crystal for infrared optical waveguides. Using this technique, KRS-5 fiber single crystals with 0.6∼1 mm in diameter were prepared at the high growth rate of 0.5∼3 cm/min up to 2m in length. The fiber crystals have a circular cross-section and high plasticity to be bent freely at room temperature.
A Simple Method to Determine the Energy of keV Neutrals
Authors: Ohya Kaoru , Mori Ichiro
Published: November 2005

The incident angle dependence of secondary electron omission from a metal surface is experimentally investigated with keV neutral bombardment. A simple method is proposed by which the energy of neutrals is determined. By applying this method, it will be possible to estimate the absolute flux intensity of the neutrals with unknown energy distribution, and the ion temperature of a Maxwellian plasma.
Studies of an Impulse Spark Using Two-Wavelength Interferometry
Authors: Muraoka Katsunori , Hamamoto Makoto , Akazaki Masanori
Published: November 2005

A two-wavelength interferometric technique has been established to measure the neutral, ion and electron densities separately in an atmospheric impulse arc channel and in the resultant shock wave. The spatial and time resolutions are ∼50 µm and \lesssim0.1 µs, respectively. The results compare favorably with the previous spectroscopic data of the spatially resolved measurement using a far more elaborate instrumentation, and of the spatially averaged, each measurable only within the arc channel.
Electrical and Structural Properties of Phosphorous-Doped Glow-Discharge Si:F:H and Si:H Films
Authors: Matsuda Akihisa , Yamasaki Satoshi , Nakagawa Katsumi , Okushi Hideyo , Tanaka Kazunobu , Iizima Sigeru , Matsumura Mitsuo , Yamamoto Hideo
Published: November 2005

Doping of Si:F:H and Si:H with P has been performed by a glow-discharge technique using PH3/SiF4+H2, PF5/SiF4+H2, PH3/SiH4+H2 and PF5/SiH4+H2 gaseous mixtures, and high conductive films over 100 Ω-1 cm-1 have been obtained. It has also been made clear from X-ray diffraction and Raman-scattering measurements that all the P-doped Si:F:H films (P/Si>5×10-4) as well as high conductive Si:H films deposited under high RF power condition are polycrystalline, while Si:H films prepared under low power remain amorphous and their conductivity is less than 10-2 Ω-1 cm-1. It is likely that film conductivity amounting to 100 Ω-1 cm-1 should be ascribed to its polycrystalline structure.
LEC Growth of GaSb Single Crystals Using Boric Oxide
Authors: Katsui Akinori , Uemura Chikao
Published: November 2005

The Liquid Encapsulated Czochralski (LEC) technique using low viscosity B2O3 containing Na2AlF6 as an encapsulant is proposed. A detail of the growth technique is described and GaSb single crystals are prepared. Mass spectroscopic analysis and Hall coefficient measurements are performed for the grown crystal and the results are compared with those for the charged material.
Detection of Fast Ions by Self-Scanning Photodiode Array
Authors: Mannami Michihiko , Kimura Kenji
Published: November 2005

The commercial self-scanning photodiode array for visible light sensing was tested as a position-sensitive detector of energetic ions. It was shown that the device can be used as a good position-sensitive detector (position resolution less than 100 µm) of energetic ions having ranges longer than a few µm in silicon, although the energy detection is difficult.
Stability of FM-Eliminated 3.39 µm He-Ne/CH4 Laser
Authors: Nakazawa Masataka , Musha Toshimitsu
Published: November 2005

The optical heterodyne measurement of two identical laser systems was carried out, in which the frequencies of the two lasers were stabilized without any frequency modulation. The Allan variance of the beat frequency fluctuation was 1.77×10-12 for an average time of 100 s, where each system was stabilized under dual feedback control consisting of a proportional and an integral feedback control.
Growth of Dislocation-Free Undoped InP Crystals
Authors: Shinoyama Seiji , Uemura Chikao , Yamamoto Akio , Tohno Shun-ichi
Published: November 2005

Dislocation-free undoped InP crystals were grown by the liquid encapsulation Czochralski method by means of a necking-in procedure. A low temperature gradient near the solid-liquid interface was essential for growth, and a temperature gradient of 55°C/cm enabled the growth of a dislocation-free crystal in a pulling of the <111> P direction up to a diameter of 15 mm. No etch pits (either D- or S-pit) were observed on the etched surfaces of wafers cut from each position of the crystal. This suggests the absence of microdefects in the crystal.
Blue-Emitting Diodes of 6H-SiC Prepared by Chemical Vapor Deposition
Authors: Nishino Shigehiro , Ibaraki Akira , Matsunami Hiroyuki , Tanaka Tetsuro
Published: November 2005

Silicon carbide (SiC) blue-light-emitting diodes with an external quantum efficiency of 2×10-5 photons/electron were prepared by the chemical vapor deposition method. Epitaxial growth of 6H-SiC has been carried out at 1800°C on a 6H-SiC substrate using the SiCl4-C3H8-H2 system. Epitaxial layers of the n and p types with appropriate carrier concentrations were obtained by doping N from NH3 and Al from AlCl3, respectively. A pn junction was prepared in one growth run by a double epitaxial process. The peak wavelength of the electroluminescence spectrum was 495 nm.
New Evidence for Defect Creation by High Optical Excitation in Glow Discharge Amorphous Silicon
Authors: Hirabayashi Izumi , Morigaki Kazuo , Nitta Shoji
Published: November 2005

New evidence for creation of dangling bonds by high optical excitation at low temperatures is presented through the time-resolved luminescence measurements and ESR measurements in glow discharge amorphous silicon.
Low Temperature Thermal Nitridation of GaAs Surfaces
Authors: Matsuno Yoichi , Matsushita Koichi , Hariu Takashi , Shibata Yukio
Published: November 2005

Thermal nitridation of GaAs surfaces can be achieved at 550°C in ammonia gas flow by anodic-oxidization of the surfaces in advance, in contrast to direct nitridation above 800°C. It was also found that the initial substitution of oxygen by nitrogen occurs at the interface between the oxide layer and GaAs, and that nitridation proceeds outwards from the interface.
Observation of Population Inversions in a Freely Expanding Pure Hydrogen Plasma
Authors: Hara Tamio , Kodera Kunihiko , Hamagaki Manabu , Matsunaga Kouzi , Inutake Masaaki , Dote Toshihiko
Published: November 2005

The possibility of a hydrogen plasmadynamic recombination laser is experimentally investigated. A high density plasma produced by a high-power quasi-steady MPD arc-jet is cooled by expanding itself into the vacuum chamber. Experimental results confirm that large population inversions between i=4–3 and i=5–3 levels exist over 12–22 cm downstream of the anode. A comparison is made between experimental data and calculated results based on the collisional-radiative model on populations of hydrogen levels.
Laser Annealing of Nb Films Prepared by Ion Beam Sputtering
Authors: Takei Koji , Nagai Kazutoshi , Inamura Takahiro
Published: November 2005

The effect of laser annealing on the superconducting critical temperature [T
c] in Nb films prepared by the ion-beam sputtering method has been investigated. Ion beam sputtered Nb films at a substrate temperature of 50°C indicated a large increase in lattice parameter and acorresponding decrease in T
c. After annealing by pulsed laser irradiations, the film showed recovery in both lattice parameter and T
c. The relation between lattice parameter and T
c of the laser annealed films is generally similar to that of the as-deposited films.
RHEED Study of InSb Films Grown by Molecular Beam Epitaxy
Authors: Oe Kunishige , Ando Seigo , Sugiyama Koichi
Published: November 2005

The surface structures of InSb films grown on (111)A, (111)B and (001)-oriented InSb substrates by molecular beam epitaxy were investigated in situ with a reflection high-energy electron diffraction technique, and the dependences of the surface reconstructions on the relative arrival rates of Sb and In and the surface temperature are reported. The change in surface structures on the (111)B and (001) faces occurs when the Sb/In ratio is about unity, and the ratio at transition does not depend on the substrate temperature. This behavior is interpreted as meaning that the sticking coefficient of Sb atoms (or molecules) is nearly unity for the Sb/In ratio \cong1.
Electrostructive Effects in Paraelectric-Ferroelectric-Antiferroelectric Phase Transitions
Authors: Uchino Kenji , Cross Leslie E. , Newnham Robert E.
Published: November 2005

Electrostrictive terms have been introduced into the Kittel free energy expression by means of a fourth-order cross term of the two-sublattice polarizations, giving rise to multiple phase transitions. Schematic p-T diagrams of the nonpolar, polar and antipolar phases are classified by the electrostrictive Ω coefficient. Spontaneous strain curves are derived for each of the four types of phase diagrams.
Accelerated Aging Characteristics of InGaAsP/InP Buried Heterostructure Lasers Emitting at 1.3 µm
Authors: Mizuishi Ken-ichi , Hirao Motohisa , Tsuji Shinji , Sato Hitoshi , Nakamura Michiharu
Published: November 2005

A marked reduction of cw threshold current, to as low as 10 mA at 25°C, was achieved in 1.3 µm InGaAsP InP buried heterostructure lasers with optimized stripe widths of 1.5–2.5 µm, resulting in the feasibility of high temperature operation up to 95°C. For the first time, high temperature cw agings at 50 and 70°C were carried out for lasers in this wavelength region, with successful results.
Photo-Excited DLTS: Measurement of Minority Carrier Traps
Authors: Takikawa Masahiko , Ikoma Toshiaki
Published: November 2005

Novel methods which take into account the temperature dependence of the amplitude of capacitance transient are presented to determine minority carrier trap parameters from Photo-Excited DLTS spectra. These methods were applied to the Fe-level in a GaAs p+n junction and the validity was demonstrated by comparing the results with the conventional junction DLTS.
Electron Microscopic Observation of PbS Islands
Authors: Nakano Kenji , Tanaka Nobuo , Mihama Kazuhiro
Published: November 2005

PbS islands prepared by the vacuum evaporation technique are observed by an electron microscope under the atomic level. For a PbS island grown on a BeO film, the image reflecting the atomic stacking as a result of the extreme thinness and the image of Pb atom chain are obtained. The observations of a Pb monolayer and a new modification of PbS are also made for PbS islands grown on cleavage surfaces of sodium chloride.
Colorimetric Characteristics of Neutral Polarizers
Authors: Ozawa Ryoji , Mada Hitoshi , Shimomura Teruo , Mizoguchi Ryuichi , Kobayashi Shunsuke
Published: November 2005

Two kinds of practical polarizers (neutral gray and bluish gray) developed for twisted nematic liquid crystal displays were examined colorimetrically using CIE 1976 (L
*
u
*
v
*) space. Colorimetric data of these polarizers were obtained and some evaluations were made.
The brightness of both polarizers is a logarithmic function of the conventionally defined transmittance (T) for white light. The color difference is a logarithmic function of the contrast ratio (C) for the neutral gray polarizer, but not for the bluish gray one.
Neon-Isotope Separation by Cataphoresis in a DC Gas Discharge
Authors: Matsumura Yoshiyasu , Abe Toshimi
Published: November 2005

In a dc discharge in a gas consisting of different isotopes of an atom, the density of the heavier isotope is enhanced at the cathode side on account of the greater amount of momentum transferred by ions to the heavier isotope than to the lighter isotope. In an experiment on Ne discharge with rather high current density, concentration ratios of 10.5% at the cathode side and 7.5% at the anode side were obtained for the heavier isotope 22Ne.
Properties of a Photoresist Film as an Insulating Layer
Authors: Ito Hideo , Mizushima Yoshihiko , Takada Akitsu
Published: November 2005

A novel technology for interlayer insulation is proposed, where photopolymerizable pohotoresist (cyclized polybutadiene) is utilized. Direct patterning of the insulating film is possible and the film is stable at least up to 300°C, therefore, the microfabrication process is very much simplified.
Microfabrication of LiNbO3 by Reactive Ion-Beam Etching
Authors: Matsui Shinji , Yamato Toshiya , Aritome Hiroaki , Namba Susumu
Published: November 2005

The ratio of the etching rate of LiNbO3 to AZ1350 at normal incidence for CHF3 ion is about 5 times as large as that for Ar ion. This high ratio is utilized to fabricate LiNbO3 blazed gratings and also LiNbO3 guided wave optical elements such as grating couplers to demonstrate that reactive ion-beam etching is a very useful microfabrication technique for LiNbO3.
Heavy Metal Gettering by an Intrinsic Gettering Technique Using Microdefects in Czochralski-Grown Silicon Wafers
Authors: Kishino Seigô , Nagasawa Kazutoshi , Iizuka Takashi
Published: November 2005

The ability of an intrinsic gettering (IG) using microdefects in Czochralski silicon wafers is verified on copper diffused wafers with the help of a neutron activation analysis (NAA). The IG technique used here is an improved double preannealing technique. It is ascertained that the copper concentration is enhanced in the bulk region where a high density of microdefects were induced. Moreover, the concentration in the denuded zone near the surface is proved to be below the detection limit of the NAA technique.
Photoacoustic Measurement of Non-radiative States and Defects in CdS and Si with ZnO Transducer
Authors: Wasa Kenji , Tsubouchi Kazuo , Mikoshiba Nobuo
Published: November 2005

Non-radiative states and defects in CdS and Si were studied at room temperature by means of a new photoacoustic (PA) technique. Signal detection was carried out by a ZnO transducer which operates in a wideband and high-frequency range. The fine structures due to A, B, C excitons and due to seven impurity states in CdS were observed as the maxima or minima in the PA spectra. It was also found that the spatial distribution of mechanical damage and defects in CdS and Si can be observed in the PA signals by scanning the laser beam spot across the sample.
Lattice Imaging Study of Boundaries in Martensite in Shape Memory Alloys
Authors: Fukamachi Masatoshi , Kajiwara Setsuo
Published: November 2005

The structure of boundaries in martensite in shape memory alloys has been studied using the lattice imaging technique of high resolution electron microscopy. Good coherence has been found between the close-packed planes at the boundaries. Such coherence makes the boundary quite mobile when an external stress is applied, and thereby a large shape change of the specimen is possible without any appreciable plastic deformation.
Piezoelectric Ceramics with Zero Temperature Coefficients of Radial Mode Resonance Frequencies
Authors: Takeuchi Hiroshi , Ito Yukio , Nagatsuma Kazuyuki , Jyomura Shigeru , Ashida Sakichi
Published: November 2005

Piezoelectric ceramics with zero temperature coefficients of radial mode resonance frequencies were developed. The chemical formula of these ceramics is (Pb0.91(La1-αNdα)0.08)(Ti0.92Mn0.02In0.06)O3. In the ceramic system, the temperature coefficient varies from -25×10-6/°C to +40×10-6/°C as the molar ratio of Nd changes from 0 to 1. When α=0.5, the temperature coefficient is less than 1×10-6/°C over the temperature range -10 to +50°C. The electromechanical coupling factor of radial mode is 0.1; mechanical quality factor is 1400; and dielectric constant ε
33

T
is 225.
Ohmic Contacts to p-GaAs with Au/Zn/Au Structure
Authors: Sanada Tatsuyuki , Wada Osamu
Published: November 2005

A reproducible technique for forming ohmic contacts with low contact resistances to p-GaAs is presented. A Au/Zn/Au multilayer structure, which is deposited by sequential evaporation of Au, Zn and Au, is found to realize a satisfactorily low specific contact resistance r
c. The value of r
c is minimized when the initial thickness of Zn layer is larger than 200 Å and the alloying temperature is around 400°C. The minimum value of r
c in Ω-cm2 is expressed as r
c=1.8×1018·p
-1.3, where p is the net hole concentration in cm-3. It is also confirmed by Auger spectroscopy that the reduction of r
c is caused by the preferential incorporation of Zn atoms into the GaAs bulk during alloying.
High Bias Frequency Operation of a Microwave SQUID at 35 GHz
Authors: Miki Yukinobu , Masumi Taizo
Published: November 2005

An rf-SQUID with the bias frequency raised to 35 GHz has been successfully operated for the first time. The principle of designing the SQUID is the naive extension of the SQUIDs at 10 GHz previously reported to the millimeter wave region. At present, the SQUID at 35 GHz has a slightly poorer signal-to-noise ratio than the SQUIDs at 10 GHz and also the highest limit of the output band-width is confined to about 1 MHz. However, several possibilities for improving the style and configuration remain for the future.
Light-Stability of Dichroic Guest-Host Cells
Authors: Seki Hidehiro , Uchida Tatsuo , Shishido Chiyoko
Published: November 2005

Light-stability of liquid crystal color display devices using guest-host interactions were investigated. It was found theoretically as well as experimentally that a decrease of absorbance of the guest-host cell was almost proportional to the exposed light intensity and time while the decrease was not large. Therefore, the lifetime can be calculated by extrapolation from the initial decreasing rate of absorbance obtained from an accelerated life test using an intense light.
Various disazo dyes with large dichroic ratios were tested and some stable dyes were found.
Long-Lived Electron-Beam-Pre-Irradiation Effect in a Compact SF6/H2 Laser
Authors: Matsuzawa Hidenori , Suganomata Shinji
Published: November 2005

The entire axial length of a SF6/H2 laser was irradiated by an e-beam pulse, which was 20 mA in peak value and 30 ns in full width at half-maximum value, prior to the main discharge pumping. The cavity was 170 mm in length. The laser power increased with e-beam pre-irradiation by a factor of two, and the effect of e-beam pre-irradiation survived for up to one second for a 10:1 mixture of SF6:H2. The survival period decreased with an increase of gas pressure and of concentration of SF6 gas. The mechanisms of the long-lived phenomena are discussed.
Photo-Electrochemical Effects of WO3 Electrochromic Devices
Authors: Yamanaka Kazusuke
Published: November 2005

The photo-electrochemical effects of electrochromic cells on WO3 electrodes are investigated. Electrochromic cells are fabricated using a WO3 electrode, a transition metal oxide counter electrode and a propylenecarbonate solution of LiClO4. The photovoltage can be detected when the cells are half or well bleached, but is undetectable with well colored ones. The photocurrent of the cell is anodic and about 0.6 µA/cm2 when illuminated by an Hg lamp, when a 1 M/l LiClO4 electrolyte is used. These photo-effects are most likely due to the nature of the n-type WO3 semiconductor.