bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal Change of Local Dependence of Emission in Neon Glow Discharge
Authors: Yamashita Masafumi
Published: November 2005

The temporal change of the radial and axial dependence of emission in an impulsive Ne glow discharge was investigated, using two kinds of plane-parallel discharge tube, to study the effect of the anode structure on the initial growth mechanism of gas discharge. The discharge tubes consisted of a plane-disk cathode tube with a plane-mesh anode and a plane-disk cathode tube with a ring anode. Analysis of the data revealed that the space charge plays an important role not only in the stationary emission state but also at the initial emission stage, and depends on the anode structure; and the ambipolar diffusion takes effect some tens of microseconds after emission begins. The radial extent of the emission is sensitive to the anode structure, but the central axial extent of the emission depends on the gas pressure.
Calculation of RFP Equilibrium in ZT-40M by Finite-Beta Model
Authors: Nagayama Yoshihiro
Published: November 2005

A simple finite-β model is proposed for calculating the reversed-field pinch (RFP) plasma equilibrium using the Grad-Shafranov equation, so as to extend the calculation to two dimensions; and the importance of the pressure profile effect on F and θ is pointed out. The equilibrium in the ZT-40M RFP plasma is obtained using this model by adjusting the parameters so that F, θ, βax and the pressure profile are consistent with the experimental data. In high-θ operation, the sawtooth oscillation is found to be accompanied by changes in the field and current profiles.
Investigation of Space Charge in High-Density Polyethylene Using Thermal-Pulse Response
Authors: Suzuoki Yasuo , Muto Hirotaka , Mizutani Teruyoshi , Ieda Masayuki
Published: November 2005

The thermal-pulse technique for the direct probing of space charge in dielectrics was modified for measurement under short-circuit conditions. The new technique was applied to polyethylene (PE) doped with impurity (antistatic agent), and proved to be effective in outlining the behaviour of the space charge in PE. A positive hetero space charge is formed near the cathode on the application of voltage. With increasing applied field, the total amount of space charge increases and its centroid shifts to the cathode. The electric field at the cathode becomes 1.6–1.7 times as large as the average field. The steep increase of current in the current-voltage characteristics is thought to be closely related to this field enhancement.
Influence of Deposition Conditions on Properties of Hydrogenated Amorphous Silicon Prepared by RF Glow Discharge
Authors: Nishikawa Satoshi , Kakinuma Hiroaki , Watanabe Tsukasa , Nihei Koji
Published: November 2005

The electrical and structural properties of amorphous silicon films prepared by pure silane rf glow dicharge have been measured as a function of the rf power, the substrate temperature, the gas flow rate and the gap between the two electrodes. The properties of the deposited films show a very different dependence on the rf power from those reported previously. The films prepared at high rf power density (1–2 W/cm2) reveal a photoconductivity comparable with that of device-grade films prepared at low rf power density (0.02 W/cm2). Increasing the gas flow rate increases the deposition rate up to 70 A/s at 2 W/cm2. The photoconductivity of films prepared at this high deposition rate is 1.2×10-5 (Ω·cm)1 at 600 nm, 1 mW/cm2. This paper discusses the deposition mechanism inducing these results.
Photo-Excited Etching of Poly-Crystalline and Single-Crystalline Silicon in Cl2 Atmosphere
Authors: Okano Haruo , Horiike Yasuhiro , Sekine Makoto
Published: November 2005

Poly-Si etching under Hg-Xe lamp irradiation in a Cl2 atmosphere was investigated. It was found that n+ poly-Si is etched by chemical reaction with Cl radicals photodissociated in the gas phase, while undoped and p+ poly-Si cannot be etched without irradiation by UV light. The primary effect of the photoirradiation is to produce electrons arising from electron-hole pair generation. The etch rates, etched features and etching products depend strongly on the electron concentration in the conduction band. The experimental results are explained by assuming that electron-attached Cl- ions penetrate into the Si lattice.
Far-Infrared Optical Properties of Quenched Germanium I. The Temperature Dependence of the Absorption and the Photothermal Ionization Spectra
Authors: Hattori Takeshi , Fujii Eiji , Kurata Tetsuyuki , Sakaji Yoshio , Mitsuishi Akiyoshi , Kamiura Yoichi
Published: November 2005

The absorption spectra and the photoconductivity spectra of quenched germanium crystal in the far-infrared region were measured at various temperatures. Seven hydrogenic line series named a, b, A, 1, 2, 3, and 4 were observed, and it is concluded from the temperature dependence of the intensity of both absorption and photoconductivity bands that the series named a and b, and 1 and 2, do not originate from two different acceptors but from one acceptor; in other words, the ground state of each acceptor, named SA1 and SA2, respectively, is split into two levels producing two series for each acceptor. The ionization energy of the shallowest quenched-in acceptor, SA1, is the lowest among those of the well-known substitutional acceptors. It is pointed out that crystals containing the quenched-in acceptors are useful as far-infrared photoconductive detectors.
Study of Exposure Atmosphere Effect on PGMA Negative Resist Cross-Linking in X-Ray Lithography Using 1–3 keV Soft X-Ray Sources
Authors: Okada Koichi , Matsui Junichi
Published: November 2005

Experimental comparisons between exposure atmosphere effects on poly (glycidyl methacrylate) (PGMA) cross-linking in Al, Si, Mo and Pd soft (1 to 3 keV) X-ray sources have been made in relation to the interaction with electrons ejected from the gold film on the X-ray mask. Under air and He gas atmosphere conditions, the exposures were performed using an X-ray mask with a thin gold film. In Al and Si X-ray sources, PGMA cross-linking markedly increases with increasing atmosphere air-pressure, whereas it remains constant and low in He gas atmosphere. Concerning Mo and Pd X-ray sources, in contrast, PGMA cross-linking is raised up to an extremely high level in both air and He gas atmospheres. The effect of the mask-to-wafer gap on PGMA cross-linking have also been examined to interpret the above phenomena. An explanation is offered which considers the ionizaion of He gas as well as air caused by electrons ejected from the gold film.
Light Absorption by Hydrocarbon Molecules at 3.392 µm of He-Ne Laser
Authors: Tsuboi Takao , Inomata Katsumi , Tsunoda Yutaka , Isobe Akihito , Nagaya Koh-ichi
Published: November 2005

The decadic molar extinction coefficients of various hydrocarbon molecules at the wavelength of 3.392 µm of the infrared He-Ne laser were measured at temperatures between 292 and 1100 K using the shock-tube technique. Methane, ethane, propane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, iso-octane, methanol, ethanol, butanol, acetone and benzene absorbed the laser light. No Doppler-or pressure-broadening of these molecules was observed except in the case of methane and ethane.
The values of the decadic molar exctinction coefficients give information on a temperature-measurement technique which utilizes Beer-Lambert's law.
Experimental and Theoretical Investigations of Flashover Properties of SF6+CCl2F2 Gas Mixtures
Authors: Okabe Shigemitsu , Kouno Teruya
Published: November 2005

SF6+CCl2F2 gas mixtures are regarded as one of the likeliest candidates as an alternative to SF6 as a dielectric gas. This paper reports experimental and theoretical investigations of the flashover properties of SF6+CCl2F2 mixtures. Measurements under a quasi-uniform electric field show that these mixtures have greater flashover voltages than either of the component gases for every mixing ratio examined; an advantage when using the mixture as an insulator. The properties of the mixtures are discussed from three different approaches, and it is concluded that the Boltzmann equation approach gives the values which agree best with the experimental values. One of the main causes of the enhanced flashover voltages lies in the change in the attachment coefficients produced by mixing. This unique property is explained theoretically for the first time.
Electromagnetic Acceleration of Macroparticles to Hypervelocities in Axisymmetric Geometry
Authors: Ikuta Kazunari
Published: November 2005

The electromagnetic acceleration of macroparticles to hypervelocities in axisymmetric geometry is considered and a new type of plasma impulse accelerator with cylindrical electrodes is proposed. The accelerator consists of a series of cylinders with their axes of symmetry on a straight line. When it is ready to be propelled, the projectile should be introduced into the second electrode together with the ablator. The projectile is propelled by the J×B force of the plasma current along the surface of the ablator, located behind the projectile.
Molecular p-n Junction Photodiodes of Langmuir Multilayer Semiconductors
Authors: Sakai Kunihiro , Saito Mitsuyoshi , Sugi Michio , Iizima Sigeru
Published: November 2005

The electrical and photoelectric characteristics of Langmuir-Blodgett film heterojunctions have been studied using organic p-n diodes consisting of monolayers of four kinds of merocyanine (MX) dyes stacked on monolayers of distearyl paraquat (PQ). A rectifying effect observed in the dark indicates that the PQ and MX monolayers act as n-type and p-type regions, respectively. The photocarriers are identified as electrons generated in the photosensitive MX monolayers. Comparison between different types of MX dyes suggests that laterial motion of carriers occurs in the p-n junctions, and that the acceptor nuclei, i.e., rhodanine in MX, play a dominant role in determining the diffusion potential with respect to the PQ n-type region.
Noise Pulses on Transient Current during Polarization Reversal of Polyvinylidene Fluoride
Authors: Takase Yoshihiko , Odajima Akira
Published: November 2005

Electrical noise pulses have been observed on the switching current of form-I PVDF. The pulses appeared only on the reverse current and not on the forward current against polarization. They were most intense in the initial region of polarization reversal, and their number increased with the electric field above a certain threshold field. Although the noise is very similar to the Barkhausen noise found in ferroelectric crystals, it is in fact a different type induced by a combination of remnant polarization and surface discharge. It is shown that an unfavorable arrangement of electrodes causes this type of noise to create an anomalous increase in current and a consequent serious error in determining the switching current.
High Mobility GaInAs Thin Layers Grown by Molecular Beam Epitaxy
Authors: Mizutani Takashi , Hirose Kazuyuki
Published: November 2005

Thin (0.5 µm) GaInAs layers are grown by molecular beam epitaxy on InP substrates with and without AlInAs buffer layers. The best electron mobilities of the layer grown without the buffer are 9700 cm2V-1s-1 at room teperature and 55500 cm2V-1s-1 at 77K in the dark. The highest mobility of the layer is 61000 cm2V-1s-1 at 60 K. Electron mobilities of the layer with the buffer are as high as 11900 cm2V-1s-1 at room temperature and 53800 cm2V-1s-1 at 77 K in the dark, while 64400 cm2V-1s-1 is measured at 77 K under an illumination condition.
Photo-Induced ESR in Amorphous C:H Films Prepared by Glow Discharge Decomposition of CH4 and H2
Authors: Watanabe Ichiro , Okumura Toshiyuki
Published: November 2005

Hydrogenated amorphous carbon films with a high content of sp3 bonds were prepared by a glow-discharge-decomposition of CH4 and H2 mixture. With exposure to light at 77 K, the films exhibit a new ESR signal with g=2.011 and a half width of 23 G in addition to an enhancement of the signal at g=2.003 due to C dangling bonds. The new signal is attributable to trapped holes in the valence-band-tail-state, and its density decreases with increasing hydrogen content in the film.
Aluminum-Line Cutting End-Monitor Utilizing Scanning-Ion-Microscope Voltage-Contrast Images
Authors: Ishitani Tohru , Kawanami Yoshimi , Todokoro Hideo
Published: November 2005

A focused-ion-beam has been preliminarily applied for aluminum-line cutting. It was found that a voltage-contrast in scanning-ion-microscope images is very useful for end-monitoring of cutting.
Optical Time Domain Reflectometer with a Laser Diode Operating as Light Emitter/Photodetector
Authors: Nakashima Takashi , Nakazawa Masataka , Seikai Shigeyuki
Published: November 2005

A new optical time domain reflectometer is proposed that uses a semiconductor laser diode (LD) as a pulse emitter and a photodetector. By employing LDs with center wavelengths of 1.31 and 1.56 µm, fault location lengths longer than 10 km were attained in both wavelengths for a graded-index multimode fiber.
Transmission Electron Microscopy of Self-Annealed Ion Implanted Silicon
Authors: Gabilli E. , Lotti R. , Lulli G. , Merli P. G. , Antisari M. Vittori
Published: November 2005

Self annealing experiments were performed on thermally insulated (100) Si samples, implanting 100 keV P+ ions at beam power densities of 15 and 25 W/cm2. Cross and plan section characterization by TEM of the specimens lead to two main conclusions about the dynamic annealing mechanism: 1) ion bombardment enhances the rate of amorphous to crystalline transformation; 2) residual crystalline islands are present on the surface. They allow a regrowth of the amorphous region both from the front and the bottom of the layer.
Uniaxial Magnetic Anisotropy Induced in Fe Films by Implantation of Tb Ions in the Presence of Static Magnetic Field
Authors: Suezawa Yoshitaka , Tsuchiya Reijiro , Gondō Yasuo
Published: November 2005

Terbium ions were implanted into Fe films at room temperature in the presence of a static magnetic field. Faraday M-H loops of those films indicated that a uniaxial magnetic anisotropy was induced by the implantations with a Tb ion dose typically higher than about 6×1014 ions/cm2 at an ion energy of 70 keV. The easy axis was parallel to the direction along which the static magnetic field was applied during the implantation. The change of M-H loop showing such uniaxial anisotropy is discussed on the basis of the multilayer structure with a Tb-Fe alloy layer sandwiched by Fe layers formed at the time of the implantation.
Direct Evidence for the DX Center Being a Substitutional Donor in AlGaAs Alloy System
Authors: Mizuta Masashi , Tachikawa Masami , Kukimoto Hiroshi , Minomura Shigeru
Published: November 2005

An experimental result that the DX center appears in GaAs:Si and GaAsd:Sn under hydrostatic pressure of about 30 kbars has been obtained for the first time. This indicates clearly that the DX center in the AlGaAs alloy system is due to a substitutional donor itself (not a complex referred to as “DX”). The change in nature from the the shallow donor to the deep DX center is discussed based on the complex multivalley conduction band structure of GaAs under various pressures and of AlGaAs with various compositions.
Epitaxial Transformation of Ion-Implanted Polycrystalline Si Films on (100) Si Substrates by Rapid Thermal Annealing
Authors: Tamura Masao , Natsuaki Nobuyoshi , Aoki Shigeru
Published: November 2005

The epitaxial realignment of CVD deposited and As+ ion-implanted poly-Si layers on (100) Si substrates has been investigated by both plan-view and cross-section TEM observations. High density annealing twins, running parallel to <110 > orientations on {111} planes, remain in epitaxially regrown films, although epitaxial realignment is realized for 1.5×1016 As+/cm2 implanted samples annealed at 1150°C for 30 s. The perfectness of a regrown film is shown by crystal lattice imaging in high-resolution electron microscopy from a cross-section sample. High-resolution TEM also reveals the existence of precipitates at the interface between the regrown film and the substrate.
Room Temperature cw Operation of Visible InGaAsP Double Heterostructure Laser at 671 nm Grown by Hydride VPE
Authors: Usui Akira , Matsumoto Takashi , Inai Motohiko , Mito Ikuo , Kobayashi Kohroh , Watanabe Hisatsune
Published: November 2005

Room temperature cw laser operation was achieved at a wavelength as short as 671 nm using an InGaAsP/InGaP double heterostructure (DH) laser on GaAs0.62P0.38 substrate for the first time. The DH structure was grown by the hydride vapor phase epitaxial method with a dual-growth-chamber reactor. With a mesa stripe laser structure, the threshold current density J
th was as low as 4.5 kA/cm2 and the characteristic temperature T
0 was 90 K at around room temperature.
Observation of Initial Stage of Al Epitaxial Growth on Si(111) by Ionized Cluster Beam Deposition
Authors: Inokawa Hiroshi , Yamada Isao , Takagi Toshinori
Published: November 2005

The initial stage of Al(111)//Si(111), Al[1̄10]//Si[1̄10] growth at room temperature by ionized cluster beam deposition was observed by reflection electron diffraction. At the initial stage of deposition (less than 10 nm in thickness) Al crystals with (100) plane parallel to the substrate surface nucleated. Three identical Al(100) crystals were found to exist simultaneously, whose azimuthal orientations were respectively Al[011]//Si[2̄11], Al[011]//Si[1̄10] and Al[011]//Si[1̄21̄].
Transmission Electron Microscopic Observation on Phase Transition Caused in Poly (vinylidene fluoride) Single Crystal by Annealing under High Pressure
Authors: Sakaoku Kiichiro , Itoh Takashi , Kunimura Satoshi
Published: November 2005

In solution-grown α-form single crystal of poly (vinylidene fluoride) (PVDF), solid to solid phase transitions (α→γ and γ→β) by annealing under high pressure have been found by transmission electron microscopic (TEM) observation. The γ-form is produced at temperatures higher than 508 K and at 320 MPa from the original α-form crystal. The γ→β transition occurs at temperatures higher than 513 K and at pressures higher than 350 MPa. It is accompanied by striations (30∼40 nm wide) along the b-axis of the γ-phase due to partial thickening, which disappear with the completion of the γ→β transition.
Hot Electron Improvement in MOS RAM's Based on Epitaxial Substrate
Authors: Satoh Shin-ichi , Eimori Takahisa , Matsumoto Heihachi
Published: November 2005

The access time shift (Δ
T
acc) through long-term stress has been measured in actual 64-kbit dynamic MOS RAM's fabricated on several types of P/P+ epitaxial substrates. The impurity concentration under the drain was found to affect the Δ
T
acc due to hot electron trapping in the gate oxide film. The thicker epitaxial layer with higher resistivity shows an advantage for hot electron improvement in future dynamic MOS RAM's.
The Energy Levels of Zn and Se in (AlxGa1-x)0.52In0.48P
Authors: Honda Masumi , Ikeda Masao , Mori Yoshifumi , Kaneko Kunio , Watanabe Naozo
Published: November 2005

The energy levels of Zn and Se impurities in (Al
x
Ga1-x
)0.52In0.48P were investigated by temperature dependent Hall measurement. The activation energy of Zn acceptor increases monotonically with increasing AlInP mole fraction x, from 25 meV at x=0 to 97 meV at x=0.75. The activation energy of Se donor begins to increase at x=0.2–0.3, and it reaches a maximum value of about 95 meV around x=0.4. As x increases from 0.5 to 1, the energy level tends to decrease to 72 meV. This compositional dependence of the energy levels in p-type and n-type materials is similar to those in AlGaAs.
Physical Solubility and Activation Energy for Molecular Hydrogen Diffusion into an Optical Fiber
Authors: Shibata Nori , Noguchi Kazuhiro , Uesugi Naoshi , Seikai Shigeyuki
Published: November 2005

Physical solubility and activation energy for molecular hydrogen diffusion into a fiber have been evaluated from the saturation values of loss increase at hydrogen-related peak wavelengths in the temperature range from 15 to 150°C. It is found that loss increase of 3.4 dB/km at the wavelength of 1.24 µm has arisen from the dissolution of 1018 molecules/cm3 hydrogen molecule, and that the activation energy for diffusion of molecular hydrogen is 10.8 kcal/mol.
Current Gain Enhancement in Graded Base AlGaAs/GaAs HBTs Associated with Electron Drift Motion
Authors: Ito Hiroshi , Ishibashi Tadao , Sugeta Takayuki
Published: November 2005

The temperature dependence of current gain in AlGaAs/GaAs heterojunction bipolar transistors with a graded bandgap base (GB-HBTs) is described. High current gain up to 1100 has been achieved at a collector current density of 6×103 A/cm2 in MBE grown GB-HBTs with a 1×1019 cm-3 doped base. The current gain in the low temperature region does not depend on temperature. This tendency is clearly explained by a nearly constant base transit time due to electron drift motion caused by the built-in field, which contrasts with the electron diffusion.
Distinction between Midgap Levels in LEC n-GaAs Determined by DLTS and Optical Absorption at 1.1 µm
Authors: Ishida Koichi , Yahata Akihiro , Kikuta Toshio
Published: November 2005

Detailed comparison has been made of the EL2 concentration determined by DLTS and the optical absorption coefficient at 1.1 µm in LEC n-GaAs. Contrary to Martin's result, the EL2 concentration is not linearly proportional to the absorption coefficient either across wafers or between ingots grown from different melt compositions. Present results indicate that EL2 is not identical to the optically observed midgap level which has a close correlation with EPD distribution.
Effect of Water Content of B2O3 Encapsulant on Semi-Insulating LEC GaAs Crystal
Authors: Emori Haruo , Kikuta Toshio , Inada Tomoki , Obokata Takeshi , Fukuda Tsuguo
Published: November 2005

Undoped LEC GaAs crystals were grown in PBN crucibles using dry and wet B2O3. The influence of the water content of B2O3 on the melt composition and the electrical properties of the crystal was examined, and it was found that when a highly Ga-rich charge composition was used, crystals grown using wet B2O3 became semi-insulating, while crystals grown using dry B2O3 were p-type conductive. The purity of crystals was investigated through SIMS analysis, LVM IR absorption measurement, and 3He activation analysis.
Maskless Fabrication of High Quality DFB Laser Gratings by Laser Induced Chemical Etching
Authors: Aoyagi Yoshinobu , Masuda Satoshi , Doi Atsutoshi , Namba Susumu
Published: November 2005

High quality submicron DFB laser gratings with 130 nm groove depth are fabricated without roughness on a grating surface by laser induced chemical etching. It is found that rigid configuration of an irradiation cell and directional etching performance of laser etching is very important to obtain high quality gratings.
An EXAFS Investigation on the Lattice Relaxation of Ni-Fine Particles Prepared by Gas Evaporation
Authors: Hida Moritaka , Wada Nobuhiko , Maeda Hironobu , Terauchi Hikaru , TSU Yasuhide , Kamijo Nagao
Published: November 2005

EXAFS measurements were made on Ni-fine particles (14–5 nm in size) prepared by the gas evaporation technique. Data were analysed by the fine adjustment method developed by Teo et al. Substantial lattice relaxation shows an increase in the nearest Ni-Ni bond distance (R
1), a decrease in the coordination number (N1) and an increase in the Debye-Waller factor (σ1). These facts can be explained as a result of the chemisorption of oxygen on the surface of fine particles.
High Resolution Electron Microscopy of Grain Boundaries in Sintered Fe77Nd15B8 Permanent Magnets
Authors: Hiraga Kenji , Hirabayashi Makoto , Sagawa Masato , Matsuura Yutaka
Published: November 2005

Grain boundaries of sintered Fe77Nd15B8 permanent magnets with different heat-treatments have been examined by high resolution electron microcopy. A b.c.c. phase with the lattice constant of a=0.29 nm was found at most of the boundaries of Fe14Nd2B grains. The b.c.c. phase and Fe14Nd2B grains are joined with smooth interfaces in the samples annealed at 870 K, which have a coercivity as high as 1000 KA/m. In samples quenched from 1350 K with a coercivity of about 500 KA/m, however, thin plates of the b.c.c. phase extend from the interfaces to the inside of the Fe14Nd2B grains, and deform the lattice spacings of (001) planes of the Fe14Nd2B matrix. These thin plates are considered to act as nucleation centers of reverse magnetic domains which reduce the coercivity of the specimen.
Sum-Frequency Generation in a Polarization-Preserving Optical Fiber
Authors: Nakashima Takashi , Nakazawa Masataka , Negishi Yukiyasu
Published: November 2005

Efficient sum-frequency generation in a polarization-preserving fiber has been successfully attained by using a 1.064 µm Q-switched and mode-locked Nd: YAG laser. The visible wavelengths due to the sum-frequency mixing are 536 nm and 564 nm, where the conversion efficiency from the pump to those visible lines reached 0.5–1% with a mode-locked peak pump power of 20 kW.
Efficient High Power-Density Operation Regime of KrF*-Laser Amplifiers for Fusion Driver
Authors: Tanimoto Mitsumori , Yaoita Akira , Okuda Isao , Owadano Yoshirou
Published: November 2005

The kinetics in electron-beam-excited KrF*-medium is numerically analysed in order to study the dependence of the fundamental laser characteristics on gas constitution, specific pump power and cavity flux. There appears the prospect of the compact fusion driver operating at considerably higher laser intensity (∼100 MW/cm2) and higher intrinsic efficiency (∼20%) in Kr-rich media at the pump power density of 10 MW/cm3 than in conventional Ar-diluted mixtures.
The Dependence of Threshold Voltage Scattering of GaAs MESFET on Annealing Method
Authors: Egawa Takashi , Sano Yoshiaki , Nakamura Hiroshi , Ishida Toshimasa , Kaminishi Katsuzo
Published: November 2005

The threshold voltage scattering of GaAs metal-semiconductor field-effect transistors (MESFET's) fabricated on commercially available LEC-grown undoped semi-insulating GaAs substrate was investigated with varied annealing methods. It was found that the threshold voltage scattering greatly depended on annealing method. SiO2 capped annealing under arsenic vapor pressure allowed very uniform threshold voltage of GaAs MESFET's over the full water.
CW Operation of 0.67 µm GaInAsP/AlGaAs Laser at 208 K Grown on GaAs Substrates by LPE
Authors: Kishino Katsumi , Kaneko Yawara , Harada Akinori
Published: November 2005

CW operation of GaInAsP/AlGaAs oxide stripe lasers with the stripe width of 8 µm was achieved at the heat-sink temperature of 208 K. The maximum light emission power and differential quantum efficiency obtained at room temperature pulse condition were 30 mW/facet and 46%, respectively. The characteristic temperature of threshold T
0 observed at the CW condition was 93 K at the tempeature of 113–200 K.
The Effect of Noble Metals on Oxidation Resistance of TbFe
Authors: Tanaka Shinsuke , Imamura Nobutake
Published: November 2005

The effect of noble metals (Pt, Au, Ag and Cu) was examined on oxidation resistance and Kerr rotation angle of TbFe. As a result, these elements generally had rather small effect on Kerr rotation angle. And Pt was found to have the most remarkable effect on the suppression of pinholes and the improvement of corrosion resistance within the composition range where Kerr rotation angle did not decrease.
A Proposal for Local Magnetic-Field Measurement in High-Temperature Plasma Devices Using a Rapid-Frequency-Scan Laser
Authors: Honda Chikahisa , Maeda Mitsuo , Yamada Takayuki , Muraoka Katsunori , Akazaki Masanori
Published: November 2005

A rapid-frequency-scan dye laser has been developed for instantaneous determination of resonance line profiles of atoms in large plasma devices. A new technique is proposed for the local magnetic field measurement inside plasmas using this laser system. Various Zeeman patterns of sodium D lines are observed with an atomic beam in the magnetic field in a single laser shot, and the absolute magnetic-field intensity and the field direction are quantitatively determined from these patterns.
Improved Heterointerface and Vertical Transport in GaAs Single Quantum Well Confined by All-Binary GaAs/AlAs Short-Period-Superlattices
Authors: Fujiwara Kenzo , Miguel Jóse Luis de , Ploog Klaus
Published: November 2005

GaAs single quantum well heterostructures (SQWH) confined by all-binary GaAs/AlAs short-period-superlattices (SPS) and by ternary Al
x
Ga1-x
As alloy were grown by molecular beam epitaxy. The results of detailed photoluminescence measurements under direct and indirect excitation conditions and of excitation spectroscopy measurements at 2 K indicate that the SPS confined SQWH exhibit superior luminescence properties due to improved binary/binary heterointerfaces and a specific vertical transport of photoexcited carriers through SPS by tunneling.
One Atomic Layer Heterointerface Fluctuations in GaAs-AlAs Quantum Well Structures and Their Suppression by Insertion of Smoothing Period in Molecular Beam Epitaxy
Authors: Sakaki Hiroyuki , Tanaka Masaaki , Yoshino Junji
Published: November 2005

Photoluminescence spectra of GaAs-AlAs quantum wells are studied to evaluate the flatness of heterointerfaces prepared by molecular beam epitaxy. We examine the correlation of the interface roughness with the measured intensity oscillations of reflective high energy electron diffraction (RHEED) during the growth. The crystal surface is found to roughen after the growth of 10 or more atomic layers. The growth interruption of 10–100 seconds prior to the interface formation is effective in achieving an atomically flat interface, leading to sharp photoluminescence with the linewidth <30 Å at 77 K even when the quantum well width is reduced to 40 Å.
Preparation and Property of Polytellurophene and Polyselenophene
Authors: Sugimoto Ryu-ichi , Yoshino Katsumi , Inoue Shigehito , Tsukagoshi Kunimitsu
Published: November 2005

Polytellurophene is prepared chemically using FeCl3 as catalyst at the first time. The electrical conductivity in the doped state is found to be relatively low, 10-6 S/cm, compared with that in polythiophene. Polyselenophene films prepared by a chemical method are found to indicate similar characteristics with those of electrochemically prepared films.
Direct Trap-Density Analysis with Junction Capacitance Transient: Trap Density Spectroscopy (TDS)
Authors: Okumura Tsugunori
Published: November 2005

An improved method (trap density spectroscopy-TDS) is proposed to precisely determine deep level parameters even when the deep-level density is extremely large and the ionized region of the deep level is restricted in the vicinity of the depletion layer edge. This method is also capable of making correction of the crossing point between Fermi level and deep level. The superiority of the TDS is demonstrated for a large amount of EL2 in HB-GaAs crystals.
Waveguide-Type Optical Modulator of GaAs Quantum Well Double Heterostructures Using Electric Field Effect on Exciton Absorption
Authors: Tarucha Seigo , Iwamura Hidetoshi , Saku Tadashi , Okamoto Hiroshi
Published: November 2005

This letter describes a GaAs/AlGaAs quantum well (QW) waveguide-type optical modulator utilizing an electric field effect on two-dimensional exciton absorption. The waveguide modulator has the same structure as QW laser diodes, and is therefore suitable for monolithic integration with a laser diode. Optical modulation was measured up to 1 Gbit/s at a driving voltage as low as 1.4 V. The 3 dB-down modulation rate was 900 Mbit/s, but higher speed operation is expected.
Lowering of Initial Anodizing Current Density due to Thin Aluminum Oxide Film on Evaporated Aluminum
Authors: Kikuchi Akira
Published: November 2005

Initial current densities under constant voltage anodic oxidation are measured to estimate aluminum oxide film thickness on aluminum. It is shown that the logarithm of initial current density ratio with and without a thin aluminum oxide on aluminum is proportional to the logarithm of the exposure time to dry air. Auger electron spectroscopy measurements show that the surface of aluminum exposed to dry air is covered with a thicker aluminum oxide film than an aluminum surface just after aluminum oxide etching by an aqueous 5% sulfamic acid.
Microstructure of CoCr Thin Films Prepared by Sputtering
Authors: Futamoto Masaaki , Honda Yukio , Kakibayashi Hiroshi , Shimotsu Teruho , Uesaka Yasutarou
Published: November 2005

The microstructure and the growth process of sputter deposited CoCr thin films are studied by transmission electron microscopy (TEM). The columnar structure of c-axis oriented CoCr grains is well established at a greater film thickness of about 100 nm. The cross-sectional TEM clearly shows the detailed structure of the initial growth layer, where the c-axis oriented grains are growing in size with increasing distance from the substrate surface. The necessity of controlling the nucleation of CoCr crystal grains at an early stage of film growth is stressed to further improve the c-axis orientation of the film.
Strong Resonant Transmission of Microwave Radiation through Metal-Metalloid Foils
Authors: Kakuno Keiichi , Kubota Taishi , Yamada Tsutomu
Published: November 2005

Remarkably enhanced resonant microwave transmissions have been found to take place in Fe78Si10B12 and Fe4.7Co70.3Si10B15 metal-metalloid foils corresponding to the FMR absorption at room temperature. The resonant transmission which takes place in the non-magnetostrictive Fe4.7Co70.3Si10B15 foil suggests that the magnetoelastic coupling is not necessarily responsible for the resonant transmission, contrary to previous reports.
Effect of Melt Stoichiometry on Electrical Activation Uniformity of Si-Implanted Layers in Undoped Semi-Insulating GaAs
Authors: Sato Takashi , Terashima Kazutaka , Emori Haruo , Ozawa Shoichi , Nakajima Masato , Fukuda Tsuguo , Ishida Koichi
Published: November 2005

The effect of melt stoichiometry on the carrier profiles in Si-implanted layers has been investigated for undoped, semi-insulating LEC GaAs grown from melts of different compositions. The electrical activation efficiency tends to increase as the crystals become As-rich. The carrier profile uniformity of the implanted layer across the wafers also depends on the melt stoichiometry. The most uniform distribution of the carrier profiles is obtained for GaAs ingots grown from melts of nearly stoichiometric composition (x=0.499 to 0.505). These results demostrate the importance of stoichiometry control in reproducible LEC growth of GaAs which permits formation of electrically uniform Si-implanted layers.
Surface Defect Formation in GaAs Layers Grown on Intentionally Contaminated Substrate by Molecular Beam Epitaxy
Authors: Watanabe Nozomu , Fukunaga Toshiaki , Kobayashi Keisuke L. I. , Nakashima Hisao
Published: November 2005

The origin of oval defects of GaAs layers grown by molecular beam epitaxy (MBE) has been studied using intentionally contaminated GaAs substrates. Diamond and Al2O3 particles, and Ga and In droplets are used as contaminants. The surface defect shape caused by the particles is very similar to that of oval defects in our MBE grown layers which have a pit in the middle. This is strong evidence that one of the origins of the oval defects is a nonreactive and nonvolatile small particle. The shape of surface defects due to Ga or In droplets is different from that due to diamond or Al2O3 particles in that the former do not have a pit. Oval defects with a pit in MBE grown layers cannot be ascribed to the group III droplets spit out from effusion cells.
Reversible Optical Recording Media with Ga-Se-Te System
Authors: Matsushita Tatsuhiko , Suzuki Akio , Okuda Masahiro , Rhee Jung Chul , Naito Hiroyoshi
Published: November 2005

Reversible optical change in a thin film system of parylene/Te
z
(Ga
x
Se1-x
)1-z
(0.6 ≤z ≤0.9, 0 ≤x ≤0.3)/parylene structure has been studied by measuring reflectance of an optical system focused laser beam to micron-sized spots. Retention time of data written by laser beam is examined under conditions of 50°C and 70% relative humidity. By surface observation with a high resolution SEM, it is found that, as the amount of Ga increases, the retention time is maximal, corresponding to the maximum diameters of microcrystallites with a cylindrical structure.
Ferroelectric Domain Structure in TGS Just below the Curie Point after Heat Treatment
Authors: Nakatani Noriyuki
Published: November 2005

The domain structure immediately after heat treatment was investigated by the nematic liquid crystal method. Just below T
c very fine domain patterns narrower than 0.5 µm in width were observed. With time, the domain pattern gradually becomes coarse. Mean domain width grows in proportion to the time elapsed since the moment of T
c, and the rate of growth is almost independent of temperature. The evolution of the domain pattern is caused by the development of large domains accompanied by the vanishing of small domains, as well as by the contraction of crooked boundaries.
A Compact Neutral Copper-Vapor-Laser Operation at Low Temperature Using the CuCl-AlCl3 Vapor Complexes
Authors: Saito Hiroshi , Taniguchi Hiroshi , Owashi Ken-ichi
Published: November 2005

A discharge-excited, repetitive pulsed copper-vapor-laser is reported. Laser action on the 510.6 nm line of neutral copper is obtained in a reservoir-temperature range of 100–400°C using the vapor complex reactions.
Fluctuation in Lattice Constant near Miscibility Gap of CdTe-Ga2Te3 System
Authors: Iwamura Yasuo , Yamamori Shuhki , Negishi Hitoshi , Moriyama Makoto
Published: November 2005

Appearance of miscibility gaps in solid solution CdTe-Ga2Te3 was describe taking account of fluctuation of lattice constants due to an increasing concentration of Ga2Te3. Introducing a new parameter F, degree of fluctuation of lattice, a relation between half-value width of rocking curve and the fluctuation of lattice parameter was obtained. It was shown that the solid solution becomes immiscible when the fluctuation of lattice parameter exceeds about 2.5%.
Influence of NO2 and White Light on the Electrical Conductivity of Polythiophene
Authors: Rabe Johan Georg , Schmidt Werner Fritz , Yoshino Katsumi
Published: November 2005

The combined effect of NO2 and white light on the electrical conductivity of polythiophene films was investigated. The results are discussed assuming the participation of photo-induced adsorption and photo-induced desorption processes.
Scanning Optical Fiber Microscope for High Resolution Laser Beam Induced Current Image Observation of Semiconductor Defects
Authors: Ogura Mutsuo , Sakaue Katsuhiko , Tokumaru Yozo
Published: November 2005

A scanning optical fiber microscope, which is composed of an optical microscope equipped with an optical fiber positioning system and a digital image processor, is realized. Laser beam induced current image of defects in a polycrystalline Si solar cell is obtained by this microscope with a spatial resolution of less than 1 µm. High resolution mapping of the deep state in LEC-GaAs is also realized by extrinsic (below band gap) photoexcitation.
Determination of Atomic Displacement Modulation in Multi-Layer Structure by X-Ray Diffraction
Authors: Harada Jimpei , Kashihara Yasuharu , Sakata Makoto , Mashita Masao , Ashizawa Yasuo
Published: November 2005

A new method of Fourier analysis is shown by which both concentration and atomic displacement modulations existing in multilayer structures can be reproduced from the measurement of the integrated intensities of satellite reflections. By applying the present method to a molecular beam epitaxy grown (GaAs)8(AlAs)8 superlattice, the atomic displacement modulation in interface region is given as well as concentration modulation.
AlGaAs/GaAs DH Lasers on Si Substrates Grown Using Super Lattice Buffer Layers by MOCVD
Authors: Sakai Shiro , Soga Tetsuo , Takeyasu Masanari , Umeno Masayoshi
Published: November 2005

AlGaAs/GaAs double heterostructure (DH) laser diodes (LD's) have been fabricated on Si substrates using (GaP/GaAsP) strained layer super lattice (SLS) and (GaAsP/GaAs) SLS buffer layers grown entirely by MOCVD. The fabricated LD's have the threshold current density of 27 KA/cm2 at 22°C and 8∼12 KA/cm2 at 77 K.
Growth of a (GaAs)n/(InAs)n Superlattice Semiconductor by Molecular Beam Epitaxy
Authors: Ohno Hideo , Katsumi Ryuichi , Takama Toshihiko , Hasegawa Hideki
Published: November 2005

Molecular beam epitaxial growth of (GaAs)
n
/(InAs)
n
superlattice semiconductors is reported. Reflection electron diffraction was used to monitor the growth process. Successful growth of (GaAs)
n
/(InAs)
n
(n=1, 2) on InP substrate was confirmed by X-ray diffraction.
Preparation of Magnetic Conducting Polymer and Its Characteristics
Authors: Yoshino Katsumi , Sugimoto Ryu-ichi , Teshima Noboru , Konishi Susumu
Published: November 2005

Magnetic conducting polymer films are prepared for the first time by impregnating metal or metal oxide powders like Fe or FeO in polypyrrole during an electrochemical polymerization.
The electrical conductivity of this magnetic conducting film is a little lower than those of non-impregnated polymer films, because of the apparently increased film thickness. Clear hystereses are observed in the magnetization (M) versus magnetic field (H) curves, from which the saturated magnetic fields and coercive fields of 64.7 emu/g and 80 Oe, of 10.5 emu/g and 305 Oe, and of 8.7 emu/g and 210 Oe are evaluated in Fe powder, FeO powder and Fe3O4 powder impregnated films, respectively.
Room Temperature Operation of 650 nm AlGaAs Multi-Quantum-Well Laser Diode Grown by Molecular Beam Epitaxy
Authors: Saku Tadashi , Iwamura Hidetoshi , Hirayama Yoshiro , Suzuki Yoshifumi , Okamoto Hiroshi
Published: November 2005

Room temperature operation at a wavelength below 700 nm has been achieved by molecular beam epitaxially grown, modified multi-quantum-well structure laser diodes whose quantum well layers are composed of Al
x
Ga1-x
As (x=0.15–0.35). These lasers have lower threshold current density than conventional double heterostructure lasers at a wavelength lower than 715 nm, and also lower value than the previouly reported MO-CVD grown single-quantum-well lasers at a wavelength lower than 690 nm. The shortest wavelength for pulse operation is 651.4 nm, whose value is the shortest among those reported so far on the room temperature AlGaAs laser diodes.
A New Formula for the Lifetime of a Round Beam Caused by the Touschek Effect in an Electron Storage Ring
Authors: Miyahara Yoshikazu
Published: November 2005

The beam lifetime caused by the Touschek effect in an electron storage ring is calculated for a round beam, extending the existing theory for a ribbon beam. The result agrees with the observed lifetime in the SOR-RING.
Residual Local Strain in Gallium Arsenide Induced by Laser Pyrolytic Etching in CCl4 Atmosphere
Authors: Takai Mikio , Nakai Hiroyuki , Nakashima Shin-ichi , Minamisono Tadanori , Gamo Kenji , Namba Susumu
Published: November 2005

Residual local strain in GaAs induced by laser pyrolytic etching in a CCl4 gas atmosphere has, for the first time, been observed by microprobe Raman scattering and ion channeling measurements. It was found that local strain of 8.6×10-3, corresponding to tensile stress of 6.4 kbar, remained in the groove etched by laser pyrolysis at a CCl4 pressure of 32 Torr with a laser power of 0.5 W, while such strain was not induced for a laser power at and below 0.4 W.
Anisotropy of Binary Mass Diffusion Constants in Nematic, Smectic A and Smectic B Phases Studied by Forced Rayleigh Scattering
Authors: Hara Masahiko , Tenmei Hiroyuki , Ichikawa Seiji , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

The binary mass diffusion constants of methyl red in p-butoxybenzylidene-n-octylaniline have been measured by forced Rayleigh scattering. Because of the different activation energies between the diffusion constants D
// and D
⊥ in the smectic A (SA) and B (SB) phases, the anisotropy D
///D
⊥ drastically changes from 0.028 to 1.67 with the phase sequence through SB, SA and nematic (N). In SB, D
// is much smaller than D
⊥, while D
// gets larger than D
⊥ in SA near the phase transition temperature to N, T
AN. The anomalous behavior at T
AN is also discussed.
Rapid Growth of AlN Films by Particle-Precipitation Aided Chemical Vapor Deposition
Authors: Komiyama Hiroshi , Osawa Toshio
Published: November 2005

A colorless and transparent AlN film 0.3 mm in thickness was grown on a quartz glass substrate by the reaction between AlCl3 and NH3 at 1073 K and atmospheric pressure. The growth rate of this film was as large as 80 nm/s. The formation of fine particles in the gas followed by their precipitation onto the substrate kept colder than the gas, due to thermophoretic and diffusional movements, was presumably responsible for this rapid growth.
Simultaneous Charged Particle Activation Analysis of Carbon and Boron in Gallium Arsenide
Authors: Nozaki Tadashi , Itoh Yoshiko , Ohkubo Yoshitaka , Kimura Toshimasa , Fukushima Hiroto
Published: November 2005

A simple method has been developed for simultaneous determination of carbon and boron in GaAs by deuteron activation analysis. The detection limit is 2×1014 atoms·cm-3 for both elements. The determined carbon concentrations are compared with the results of IR spectrophotometry.
Dislocation Propagation into MBE Grown GaAs Layers under the Condition of Misfit Dislocation Generation
Authors: Shinohara Masanori , Ito Tomonori , Yamada Kohji , Imamura Yoshihiro
Published: November 2005

Dislocation propagation under a misfit dislocation generation condition into an MBE grown GaAs layer from a nearly dislocation-free indium-doped substrate and the epi-layer/substrate interface is investigated. Thermally stress-induced substrate dislocations of 60°-type lying on {111} planes are usually forced to bend at the interface. However, grown-in substrate dislocations with composite Burgers vectors, which are propagated from a seed-crystal, are not forced and penetrate into the epi-layer. Moreover, dislocations independent of substrate dislocations emerge in the epi-layer from the interface.
Vacuum Ultraviolet Detector
Authors: Shao Chun-Lin , Tomita Kazuhiro , Jimbo Takashi , Umeno Masayoshi , Hattori Shuzo
Published: November 2005

A new vacuum ultraviolet detector has been fabricated. A sample was made using a crystalline quartz plate on the surface of which a metal electrode was deposited. It has been experimentally established that the sample is sensitive to VUV radiation, and the external quantum efficiency is estimated to be higher than several percent. The new photodetector also has very good stability and should be a practicable new VUV photodetector.
Planar Type p-Channel InSb-MAOSFET
Authors: Fujisada Hiroyuki
Published: November 2005

Planar type p-channel InSb-MAOSFET is fabricated by anodic oxidation and alumina sputtering for MAOS gate structure, and Be ion implantation for source and drain. An excellent on-off ratio of the order of 105 is obtained in the drain current. Results also indicate that threshold voltage depends on various conditions of the application of gate and drain voltages and that a time dependent response is observed for the drain current.
Structure of MOCVD Grown AlAs/GaAs Hetero-Interfaces Observed by Transmission Electron Microscopy
Authors: Kajiwara Kazuo , Kawai Hiroji , Kaneko Kunio , Watanabe Naozo
Published: November 2005

AlAs/GaAs monolayer scale superlattices were grown by atmospheric pressure-MOCVD and the layer structure was observed with a transmission electron microscope (TEM). Clear stripes with high contrast in the TEM lattice image indicated ultra-abrupt hetero-interfaces. The TEM image and the transmission electron diffraction pattern of the superlattices showed that the hetero-interface was nearly free of island-like structure even in such a very short period superlattice as (AlAs)5-(GaAs)2.