bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Performance of Discharge-Pumped XeCl Laser Using Ar/He Diluent
Authors: Hiramatsu Mineo , Goto Toshio , Hattori Shuzo , Yamabe Chobei
Published: November 2005

The performance of the discharge-pumped XeCl 308 nm excimer laser with automatic preionization has been improved through the use of an Ar/He mixture as the diluent gas. With Ar/He diluent, a higher laser peak power than that in Ar or He diluent and a longer lifetime than that in Ar diluent have been obtained below 2 atm, making it possible to fabricate a simpler laser tube.
Steady-State Solutions of Propagating LIB with Rotaing Motion
Authors: Murakami Hiroyuki
Published: November 2005

Accurate steady-state solutions of a rotating and propagating LIB (light ion beam) are obtained using distribution functions. The effect on these solutions of the deviation from charge neutralization and current non-neutralization is considered. It is shown from the profiles of the solutions based on the distribution functions that an LIB is hollow when the protons in the beam have the same axial velocity but the same or different azimuthal velocities. A practical solution is given in the case of a beam having different axial and azimuthal velocities. This solution satisfies the stability condition shown in the paper preceding the present one.
Diamagnetic Measurement of JFT–2 Plasma Heated by Neutral Beam Injection
Authors: Maeno Masaki , Sengoku Seio , Yamamoto Shin , Suzuki Norio , Yamauchi Toshihiko , Kawashima Hisato , Miura Yukitoshi
Published: November 2005

A neutral beam was injected into the plasma in the JFT–2 tokamak, and the poloidal beta value βp of the plasma was determined by a diamagnetic method in which the change in the magnetic flux due to the plasma was obtained by measuring the very small perturbation of the current in the tokamak's toroidal field coil. The ratio of the perturbed to unperturbed currents in the coil was found to be (2–3)×10-4. The poloidal beta value βpd determined by this method agrees within experimental error with that obtained from magnetic and energy profile analyses. βpd increases linearly with the total power P
net deposited by the neutral beam in the plasma when P
net=1.5 MW. The heating efficiency of the beam injection heating was found to be lower than that of Joule heating.
Simulation of a Reversed-Field Theta-Pinch Plasma by a Zero-Dimensional Model Including Effect of Impurities
Authors: Seki Masaharu , Himeno Shun-ichi , Aso Yoshiyuki , Hirano Kei-ichi , Enoto Takeaki , Ozawa Yasutomo , Yamaguchi Sataro
Published: November 2005

A zero-dimensional rigid rotor model is useful in investigating post-implosion behavior in a reversed-field theta-pinch plasma including impurities. The thermal sheath length δ and the inverse of the gradient length ε
n can be determined for the numerical calculation to give better agreement with the experimental results on the initial time behaviors of τp, τe
th, T
e and T
i, where τp is the particle confinement time, τe
th the thermal conduction time, and T
e and T
i are the electron and ion temperatures, respectively. The numerical results of the total electron number N
e, electron density n
e, energy confinement time τE, τe
th, T
e, and T
i, and energy flows with impurity for Z
eff=2 are closer to the experimental results than those without impurity for Z
eff=1, where Z
eff=2 is the effective ionic charge taken from the experimental measurement. The calculation shows that τE and τe
th are much more sensitive to Z
eff than τp is.
Low-Frequency Dielectric Relaxation in Polycarbonate and Polypropylene Blends
Authors: Pillai P. K. C. , Narula G. K. , Tripathi A. K.
Published: November 2005

Low-frequency dielectric relaxation was studied in compression-molded thin films of polypropylene (PP)-polycarbonate (PC) blends of various weight ratios by analyzing the transient currents. The effect of various parameters such as field strength, charging time and charging temperature on the transient discharge currents was studied. Comparative studies of the isochronal characteristics (i.e. current-temperature plots at fixed times) with the thermally-stimulated depolarization and polarization currents were also carried out in order to find possible correlations between the phenomena observed by the different methods. All the results indicate that polarization (or dielectric relaxation) in the polyblends is due to induced dipoles formed by deep trapping of charge carriers-injected as well as bulk-produced.
The Structural, Dielectric, Raman-Spectral and Low-Temperature Properties of Amorphous PbTiO3
Authors: Nakamura Terutaro , Takashige Masaaki , Terauchi Hikaru , Miura Yu-ichi , Lawless W. N.
Published: November 2005

Amorphous ribbons of pure PbTiO3were obtained by the rapid solidification technique and were confirmed to be in the amorphous state by several different experimental techniques. Structural studies revealed clusters with radii up to about 150 Å, larger than those so far found in other materials such as metals or semiconductors in the amorphous state. Dielectric and Raman spectral studies confirmed that the material remains in the amorphous state indefinitely. Low-temperature studies showed that not only the amorphous state but also the crystalline state of PbTiO3has a dielectric constant minimum in the mK region, a characteristic of the amorphous state.
Switching Characteristics of Ferroelectric Liquid Crystal DOBAMBC
Authors: Orihara Hiroshi , Ishibashi Yoshihiro
Published: November 2005

Nucleation and domain growth in the switching of DOBAMBC were investigated by means of sequential microscope photographs taken with pulsed light and by laser light transmission. It was found that the electric field dependences of the switching time t
s, the domain wall velocity v and the density of nuclei n obey power laws. The essence of the switching behavior is described well by the Avrami formula.
Characterization of Solid-Phase Epitaxially-Grown Silicon Films on SiO2
Authors: Tamura Masao , Tokuyama Takashi , Yamamoto Hiroshi , Ishiwara Hiroshi , Furukawa Seijiro
Published: November 2005

Lateral solid-phase epitaxial (L-SPE) films of vacuum-deposited Si on SiO2 have been examined, mainly through TEM observation, and compared with (100) vertical solid-phase epitaxial (V-SPE) films. Typical defects in L-SPE layers with a rough growth front are high-density twins and dislocations, which are generated regardless of whether the films are <100> or <110> laterally-grown films. On the other hand, in V-SPE layers containing low-density short dislocations, {111} and {110} facets are formed at the <110> and <100> directed oxide window edges, respectively. The facets are thought to act as a barrier for the change from V-SPE to L-SPE across the SiO2 edge. Successive 1050°C high-temperature heat treatment generates interstitial-type faulted and unfaulted dislocation loops in Si+ ion implanted V-SPE layers. This is in contrast to the reduced dislocation density resulting in L-SPE layers containing no residual amorphous regions after the first 600°C annealing.
Lateral Photovoltaic Effect in the Weakly Inverted and in the Depleted MOS Interface Layers
Authors: Shikama Tomokazu , Niu Hirohiko , Takai Munezo
Published: November 2005

The lateral photovoltage V
nL in the weakly inverted and in the depleted interface layers of an MOS with p-Si substrate has been measured as a function of the gate voltage V
G using the following three quantities as parameters: the chopping frequency ω of the irradiation, the light power and the temperature T.
In a range of low light powers and low temperatures, V
nL depends strongly on ω and T; i.e. over a wide range of V
G, |V
nL|-1 increases with increasing ω and with increasing T, and there appears a dip between two peaks in the V
nL vs V
G curve.
This behavior of V
nL has been explained by the trapping of conduction electrons by the interface states in the forbidden band.
Copper Vapor Laser Pumped Dye Amplifier of a CW Dye Laser
Authors: Namba Kazumi , Ida Jiro
Published: November 2005

The characteristics of a pulsed dye amplifier of a cw dye laser beam pumped by a copper vapor laser were investigated. The results show that the system is an efficient tunable source for laser spectroscopy with high average power, good spectral purity and excellent frequency tunability. Using Rh6G, RhB and DCM, the two-stage amplifier covered the spectral range of 575–670 nm with a second-stage conversion efficiency greater than 7%.
Laser Microprobe of Alkali Elements in Organic Compounds
Authors: Yamamoto Takashi , Munakata Toshiaki , Nomiya Yoshio , Tsukakoshi Motowo , Kasuya Takahiro
Published: November 2005

Laser microprobe mass-spectroscopic detection was applied to inorganic elements in an organic specimen with the intention of obtaining the basic characteristics of the specimen for biomedical application. The fourth harmonic of an Nd:YAG laser was employed as the radiation source. An organic compound containing alkali elements of low concentration and high homogeneity was used as the specimen. The time-of-flight measurements and mass-spectroscopic observations were performed for ions emerging from the laser-produced microplasma. The highest kinetic energy of ions E
h and the total number N
T of Na ions were found to be scaled by the laser intensity φ1 as E
h∝φ1
0.39 and N
T∝φ1
1.1, in the range of 3×107 to 3×108 W·cm-2. The kinetic energy of ions extended to several hundred eV for laser irradiation of the order of 108 W/cm2, and spread over about 100 eV as evaluated from the FWHM of the TOF profiles. A sensitivity of better than 10-8 g was achieved with ease for a single-shot laser mass-analytic detection of Na, Ca, and Cs in the organic compound.
Finite-Element-Analysis of Fields Radiated from ICRF Antenna
Authors: Yamanaka Kaoru , Sugihara Ryo
Published: November 2005

The electromagnetic fields radiated from a loop antenna on which an oscillating current flows across the static magnetic field B
0 are calculated in several simple geometries by the finite element method (FEM) and by analytical methods in a cross section of a plasma cylinder. The wave number along B0 is assumed to be finite. Good agreement between FEM and the analytical solutions is obtained, demonstrating the accuracy of the FEM solutions. The method is used to calculate the fields from a half-turn antenna, and acceptable results are obtained.
Measurements of Intensity Scaling of Ablation Pressure at 10.6 µm and 1.05 µm Laser Wavelengths
Authors: Daido Hiroyuki , Tateyama Ryuzi , Ogura Kazuki , Azechi Hiroshi , Nakai Mitsuo , Yamanaka Tatsuhiko , Mima Kunioki , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

This paper describes measurements of the ablation pressure for 10.6 µm and 1.05 µm laser irradiation using thin-foil acceleration observed by X-ray backlighting and X-ray streak shadow graphs of the implosion of a spherical target. At an absorbed laser intensity of 1014 W/cm2, the ablation pressure was more than 10 Mbar for laser wavelengths of 10.6 µm and 1.05 µm. The results are compared with theories based on the self-regulated flow model and the flux-limited thermal conduction model.
Relationship between Toroidal Flux Enhancement and Instabilities in a Reversed Field Pinch
Authors: Tsukada Tokuaki , Hayashi Izumi
Published: November 2005

The enhancement of the toroidal magnetic flux in a reversed field pinch is studied experimentally in a toroidal plasma device. The perforated shell-type coil used in this experiment enables us to observe the full toroidal plasma by an image-converter camera. It is found that a helical luminous filament appears around the main plasma column only when the toroidal field at the wall of the discharge tube begins to reverse and when the toroidal flux in the tube is enhanced.
Numerical Calculation of “Actual” Radial Profile of Ion Temperature from “Measured” Energy Spectra of Charge-Exchanged Neutrals
Authors: Nakamura Kazuo , Hiraki Naoji , Toi Kazuo , Itoh Satoshi
Published: November 2005

The energy spectra of charge-exchanged neutrals are observed in the TRIAM-1 tokamak by vertical scanning of the neutral energy analyzer. The “apparent” ion temperature obtained directly from the energy spectrum observed in the peripheral region is much higher than that predicted by neoclassical transport theory. The “actual” ion temperature profile is derived numerically from the energy spectra observed at various positions taking into account the wall-reflection effect of neutrals and the impermeability of the plasma. As a result, the “actual” ion temperature profile is found to agree well with that predicted by neoclassical transport theory.
Flight-Time Spread of Uniform Field Sector Magnet System for Use in Nuclear Life-Time Measurements
Authors: Sakata Akihiko , Mamei Masayuki , Yamada Yoshihiro , Ōhira Kyozo
Published: November 2005

A nuclear life-time measurement apparatus incorporating a deflecting β-ray spectrometer with electron pre-accelerator has been constructed. A new arrangement consisting of two double angular focusing sector magnets based on the principle of symmetry has been devised so as to reduce the time spread in the spectrometer, which up till now has been the weak point of such systems. The time spread in the spectrometer was estimated to be \cong0.1 ns by a simulation method, and good agreement was obtained between this estimated value and the experimental value. A prompt time resolution of 1.25 ns (FWHM) was obtained. The half-lives of the 199 and 401 keV levels in 75As were measured with an acceleration voltage up to 30 kV to check the reliability of the apparatus. The values were found to be 0.87±0.04 ns and 1.74±0.05 ns, respectively, in good agreement with previous measurements.
Slow Tumbling Motion of Nitroxide Spin Probe/Labelled PMMA Studied Using Saturation Transfer ESR and Saturation Parameter Methods
Authors: Ohno Keiichi , Ishii Tetsuyoshi , Sohma Junkichi
Published: November 2005

The slow tumbling motion of nitroxide spin probe/labelled poly-(methyl methacrylate) (PMMA) was investigated by the saturation transfer ESR (ST-ESR) and saturation parameter methods. The rotational correlation time 10-6 to 10-5 s of the motion was observed in the temperature range from -80°C to -20°C and was found to be due to the side chain of PMMA.
Thomson Scattering Device Calibrated by Rotational Raman Scattering of Hydrogen
Authors: Yamauchi Toshihiko , Yanagisawa Ichiro , Kawashima Hisato
Published: November 2005

The anti-Stokes rotational Raman scattering from gaseous hydrogen at a pressure of 60–200 Torr and 293 K was used to calibrate the intensity of the Thomson signal scattered from the JFT-2M tokamak plasma by the incidence of ruby laser light.
The electron temperature and density profiles were calculated through a calibration constant obtained with the Raman scattered light and LED light, and the error in the electron density was found to depend on the uncertainty in the differential Raman cross-section of the hydrogen, the density of the gas, the electron temperature, and the photoelectron statistics.
Effect of Pressure on the Crystallization of Amorphous Fe–B Alloys
Authors: Ogawa Yoshinori , Endo Shoichi , Kiritani Michio , Fujita Francisco E. , Fukizawa Akira
Published: November 2005

An experiment was carried out at high pressure on the crystallization of Fe–B amorphous alloys. Electrical resistance measurements showed that the temperature of the onset of crystallization, T

x
, for Fe86B14 and Fe75B25 alloys, increased monotonically with increasing pressure up to 100 kbar, suggesting that the diffusion of atoms for crystallization was suppressed by the pressure. With Fe86B14, a drastic decrease in T

x
was observed at about 100 kbar. In-situ X-ray diffraction at 113 kbar showed that γ-Fe crystal was precipitated instead of α-Fe. The reduction in the volume of the alloy associated with the precipitation of γ-Fe, which has a specific volume smaller than that of α-Fe, seems to be responsible for this drop in T

x
. This anomaly was not observed with Fe75B25, and Fe3B only was precipitated.
Binary Mass Diffusion Constants in Nematic Liquid Crystals Studied by Forced Rayleigh Scattering
Authors: Hara Masahiko , Ichikawa Seiji , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

The binary mass diffusion constants of methyl red in the nematogens MBBA and 5CB were measured by forced Rayleigh scattering (FRS). The diffusion constants in the direction parallel to the director orientation, D
//, are always larger than those perpendicular to it, D
⊥; D
///D
⊥=1.6 for both MBBA and 5CB at room temperature. The temperature dependence is of the Arrhenius type except near the phase transition temperature of 5CB, where the values tend to deviate downwards. A comparison between the results obtained by other methods and those obtained by the present method suggests that the binary mass diffusion constant of methyl red obtained by FRS is a good measure of the self-diffusion constant.
Effects of Impurity States on the Anomalous Specific Heat of AgCl:S
Authors: Sonoike Sanemi , Nagashima Toshio
Published: November 2005

The total heat of dissociation of silver aggregates in silver chloride crystal doped with sulphur is studied as a function of the sulphur concentration by measuring the anomalous specific heat of the crystals. The endothermic and exothermic reactions are derived based on a model consisting of two trap levels which trap the dissociated silver atoms in the crystal. The calculations are fitted to the experimental results.
Piezoelectric Properties in Uniaxially Drawn Copolymers of Vinylidene Fluoride and Trifluoroethylene
Authors: Wen Jian Xun
Published: November 2005

The piezoelectric constants d
3i
and e
3i
(i=1-3) have been determined as a function of the remanent polarization P
r in uniaxially drawn and poled copolymers or vinylidene fluoride and trifluoroethylene or composition 52/48, 65/35, and 73/23 mol%. The e constant is linearly proportional to P
r, while the d constant is nonlinear because of an increase in the elastic constant at high P
r. The observed values of e
31, e
32 and e
33 are compared with prediction of the dimensional effect: e
31=e
32=0, e
33=-P
r. It is found that the dimensional effect is dominant in the observed activity of 73/27 copolymer, while in the 52/48 copolymer there is another dominating mechanism. The electrostrictive coupling characteristic of ferroelectric materials is examined and its additional contribution is shown to explain the observed piezoelectric activities in the copolymers having relatively low Curie temperature.
Direct Measurement of Void Discharge and Estimation of AE Source
Authors: Iida Shoji , Sugiyama Yasuo , Itoh Shohachiro
Published: November 2005

It was estimated from statistical characteristics that the frequency distribution of partial discharge would be of the Poisson type, and this prediction was proved by experiment. It was also found that with several groups of voids, distribution curves with the same numbers of groups were produced, and the distribution curves had a tendency to deform from the Poisson distribution according to the high voltage applied.
Measurements were carried out by detecting the AE (Acoustic Emission) generated by void discharge when a voltage was applied to the void material. This method has the advantage that it enables the void discharge to be detected directly.
The rapid expansion of the air in the voids is thought to be the source of the AE signal.
Punchthrough Probability of Josephson Logic Gates
Authors: Yamada Hajime , Tanaka Toshiro , Ichimiya Yoshichika
Published: November 2005

The operating speed of Josephson logic gates is restricted by the punchthrough phenomenon, which has a probabilistic nature. The punchthrough probability for identical operating speeds varies according to the type of gate. This paper reports a study of the punchthrough probability for two-junction interferometers and resistor-coupled gates. With the interferometers, the punchthrough probability is predicted from the equation of motion for the center of the phase of the two junctions. With the resistor-coupled gates, the punchthrough probability is calculated by taking into account the dumping effect produced by the resistors of the gates. The predictions are confirmed by computer simulation.
Ac Surface Photovoltages in Strongly-Inverted Oxidized p-Type Silicon Wafers*
Authors: Munakata Chusuke , Nishimatsu Shigeru , Honma Noriaki , Yagi Kunihiro
Published: November 2005

Surface photovoltages in Si wafers excited with a chopped 559 nm-wavelength photon beam are analysed using a new half-sided junction model. In this model, the wafer surface with the depletion layer is considered to be one half of the p-n junction. Chopping frequency ranges from 2 Hz through 20 kHz. Four 76 mm-diameter p-type Si wafers having resistivities of 260, 92, 17 and 1.0 mΩ m are used after forming 360 nm-thick wet-oxide layer on their front surfaces. In these wafers, photovoltage increases with resistivity. In three high-resistivity wafers with strongly-inverted surfaces, the inversion capacitances and conductances limit the photovoltages at low frequencies. The obtained inversion time-constant is 7 s for the 17 mΩ m wafer.
Photovoltaic Properties of Sandwich Cells Prepared with Fluoroaluminium Phthalocyanine
Authors: Shimura Michiko , Toyoda Arata
Published: November 2005

The electric and photovoltaic properties or fluoroaluminium phthalocyanine have been studied with a view to the fabrication or organic semiconductor solar cells using this material. The surface resistance or a sublimed AlPcF film was found to fall off abruptly when the vacuum was broken, probably owing to the adsorption or oxygen. Measurement of the thermoelectric motive force showed that the AlPcF film was a p-type semiconductor. Metal/AlPcF/Au sandwich cells showed rectifying behavior: forward bias made the metal electrode negative with respect to Au. When light of wavelength greater than 480 nm was shone onto the Sn electrode of the sandwich cell, a short-circuit photocurrent of 32 µA and an open-circuit photovoltage of 320 mV were obtained. The fill factor was 0.3 and the energy conversion efficiency was 0.4% for the light which passed through the Sn electrode.
Secondary Ion Emission from Si Subjected to Oxygen Ion Bombardment
Authors: Ohwaki Takeshi , Taga Yasunori
Published: November 2005

The secondary ion yields and energy distribution of positive ion species sputtered from an Si surface under O+
2 ion bombardment were measured using UHV-SIMS. The SIMS spectra obtained contained peaks due to the following cluster ion species; Si+, SiO+, Si+
2, Si2O+, SiO+
2, Si2O+
2 and Si2O+
3. The secondary ion yield was found to exhibit a depend on the primary ion energy. The secondary Si ion yield increased gradually with increasing energy, but the secondary cluster ion yield first increased and then decreased gradually through a maximum at an energy of 10∼15 keV. The most probable energies of cluster ions such as Si2O+ and Si2O+
3 were also found to vary with the primary ion energy. The FWHM values in the energy distributions decreased linearly with increase in the mass of the sputter ion species, while the tail factor decreased with the mass of the cluster ions.
Comparative Study of Various Models of Energetic Ion Generation from Plasma Focus
Authors: Tanimoto Mitsumori , Ueno Isao , Koyama Kazuyoshi , Matsumoto Yuji
Published: November 2005

Various simple models are developed to derive a scaling law for the kinetic energy of fast ions generated from plasma focus devices. Various electric fields are considered as the driving source; those induced by rapidly-increasing plasma inductance, those induced by enhanced resistivity, and these induced by macro- and microscopic plasma instabilities. The electric field and the kinetic ion energy are shown to be represented by a universal analytical scaling law. The results are also compared with experimental observations.
Computer Simulation of Range and Damage Distributions of He ions in SiC
Authors: Miyagawa Yoshiko , Ato Yasuro , Miyagawa Soji
Published: November 2005

The exrerimental projected ranges of various heavy ions in an amorphous Si target in the energy region where the nuclear stopping dominates are compared with calculations using the computer simulation program SASAMAL with the Lenz-Jensen, Moliere, Thomas-Fermi and Kalbitzer-Oetzmann (KO) screening parameters. In most cases, the best agreement was obtained with the KO screening parameters.
The projected range distributions of He ions implanted in an SiC target were calculated using SASAMAL with KO screening parameters. The agreement between the SASAMAL(KO) results and our experimental data was satisfactory when the electronic stopping parameter k=1.3 k
NS was used. The energy and the depth distributions of the primary knock-on atoms and the depth distributions of the recoil energy density with various values of the displacement energy E
d were also calculated using SASAMAL(KO) for He ions in SiC.
Mechanism of Charge Build-up on Polymer Powders after Passage through Metal Pipes
Authors: Masui Noriaki
Published: November 2005

The electrification of polymer powders transported through numerous charging units (up to 12 units) was studied at a mean particle speed v=7 m/s∼26.4 m/s and a load ρ=0.006 kg/m3∼2.5 kg/m3. Each charging unit consisted of a combination of a U bend and a straight pipe. The charge/mass ratio of the powder passing through the units grew exponentially and tended to saturate as the number of units increased. The powder particles were found to be electrified mainly in the U-bend pipes. The electric field E
s caused by the charged particle cloud has a considerable effect on the saturation tendency of nylon 12 powder, but no effect on that or HDPE powder.
A Diffusive Mode in KH2PO4 Studied with a Tandem System Using a Fabry-Perot Interferometer and a Double-Grating Monochromator
Authors: Sakai Akira , Yagi Toshirou
Published: November 2005

A Fabry-Perot interferometer and a double grating monochromator were used in tandem to construct a new spectroscopic system with high resolution over a wide frecquency range. The system was used to measure the low-frequency spectra of KH2PO4 in the x(y
x)y configuration near T
c without distortion. The diffusive central component of the spectrum was successfully analyzed using a Debye-type susceptibility function with a polarization relaxation time τ=τ0
T
0/(T-T
0), where τ0=1.57×10-13 s and T
0=118.7 K.
Computer-Aided Design of a New High-Performance Mass Spectrometer
Authors: Matsuo Takekiyo
Published: November 2005

A new procedure for designing a high-performance mass spectrometer is described. TRIO-FIT, a computer program which utilizes an automatic fitting function, is employed for the purpose. As an example of TRIO-FIT's usefulness, an ion-optical design for a high-performance mass spectrometer (high resolution, mass range, and transmission) is developed from several alternatives. A mass resolution of 300,000 and a mass range of up to M/Z 200,000 can be expected from this system. A method of examining the practicability of a given mass spectrometer design is also described, and this procedure is demonstrated on the proposed design of the high performance instrument.
MOS C-t Evaluation of Reactive Ion Etched Silicon Substrate
Authors: Ozaki Yoshiharu , Ikuta Kenji
Published: November 2005

The distribution and electrical activity of damage in Si substrates created by reactive ion etching(RIE) in CF4+H2 using a metal contamination free chamber was studied by MOS C-t measurement. RIE damage is divided into primary and secondary damage. Primary damage is caused by the penetration of carbon generated in the decomposition of reactive gas, and restricted to the region from the top surface to a depth of 3000 Å. Secondary damage is extended to more than a few µm in depth, although its intensity is lower than primary damage. It is also shown that electrical activity of secondary damage is affected by the original defects in the Si substrate.
Electronic Properties of Post-Hydrogenated Lightly-Boron-Doped CVD Amorphous Silicon
Authors: Nakashita Toshio , Kohno Kenji , Imura Takeshi , Osaka Yukio
Published: November 2005

Lightly-boron-doped CVD amorphous Si with a doping ratio between 3.3×10-7 and 2.5×10-5 was hydrogenated by hydrogen plasma annealing, and the electronic properties including photoconductivity and photoluminescence were investigated. At a doping ratio of 4×10-6 amorphous Si with the intrinsic property is produced, of which the photoconductivity at AM1 (100 mW/cm2) is 3×10-5 Ω-1cm-1, the localized state density in the mobility gap is lowest, and the photoluminescence intensity is highest. It is suggested that some boron atoms become inactive, forming B-H bonds with penetrating hydrogen atoms at doping ratios above 4×10-6.
Effect of Molecular Order on Photoconduction of Polyimide
Authors: Iida Kazuo , Waki Misao , Nakamura Shuhei , Ieda Masayuki , Sawa Goro
Published: November 2005

The photoconduction of commercial polyimide films and polyimide films synthesized in our laboratory was studied, and the photocurrent of the commercial film was found to be smaller than that of the synthesized film. As the film was stretched, the photocurrent increased. X-ray diffraction indicated that as the film is stretched, the molecular order is lowered. It is concluded that the photocurrent in polyimide is closely related to the molecular order.
Observation of T-Wall Domains in NiO Crystal by an Optical Double-Diffraction Method
Authors: Namikawa Kazumichi , Terui Kenji
Published: November 2005

An optical version of the mirror reflection method has been developed to provide more convenience and flexibility. This method has proved better than conventional X-ray micrography, if the sample is a crystal with mosaic structure. The system has been used to obtain interference fringes, enabling the tilt angle between neighbouring domains to be estimated.
Unmodulated-Type Frequency Stabilization of a PbSnTe Diode Laser
Authors: Okumura Kenichiro , Ohi Misao
Published: November 2005

The frequency of a PbSnTe diode laser around 10.6 µm was stabilized to one of the absorption lines of C2H4 without frequency modulation by controlling the injection current. Two different methods were tried: one used light after absorption and the other used light after absorption and reference light for comparison. From the analysis of the linear approximate models of the experimental systems, the frequency fluctuations, which here are taken to represent the peak-to-peak widths over a period of 5 minutes, were estimated to be 9.3×10-8 in the former case and 2.2×10-8 in the latter. The analysis also clarified that frequency fluctuations are underestimated when obtained by the usual method, which is a simple conversion of the control error signals. These values were over one order smaller than the values obtained from the linear approximate models.
Vapor Phase Epitaxial Growth of ZnSe Using Zinc and Selenium as Source Materials
Authors: Matsumoto Takashi , Nonaka Hideyuki , Ishida Tetsuro
Published: November 2005

Epitaxial layers of ZnSe have been grown on GaAs substrates at temperatures of 550–850°C in a hydrogen flow system using zinc and selenium as the source materials. The layers on the (111)Ga faces show flat-topped triangular growth patterns and have the twinned zincblende structure. The layers on the (1̄1̄1̄)As faces grown at temperatures above 700°C show triangular growth pyramids and have the twin-free zincblende structure, while those grown at temperatures below 700°C have the twinned zincblende structure. The photoluminescence spectrum at 80 K consists of the exitonic band at 2.79 eV, the free-to-bound band at 2.70 eV and deep-level emission bands at 2.2 and 2.0 eV. The deep-level emission bands decrease in intensity as the growth temperature is lowered.
DX Deep Centers in AlxGa1-xAs Grown by Liquid-Phase Epitaxy
Authors: Tachikawa Masami , Mizuta Masashi , Kukimoto Hiroshi
Published: November 2005

Deep levels, the so-called DX centers, in the Al
x
Ga1-x
As alloy system grown by liquid-phase epitaxy (LPE) were investigated by junction-capacitance spectroscopy. The dependence of the activation energy of the DX center in Sn-doped Al
x
Ga1-x
As on the alloy composition was determined by DLTS. This dependence seems to reflect the change in the nature of the conduction bands in this alloy system. The other donor species studied: Si, Te and Se, were also found to form DX centers. An anomalously high concentration of DX centers was determined using low-temperature C-V techniques.
Gas-Flow Cryostat
Authors: Mizuno Kenichi , Matsui Atsuo , Nishimura Hitoshi
Published: November 2005

A cryostat designed to cool specimens with cold gas has been constructed. Its working temperature range is from room temperature to 4.38 K, although it is normally operated down to 5.1 K. Three specimens can be mounted in the cryostat simultaneously, and their temperature can be reduced at as slow a rate as 0.1°C/min. The luminescence emitted from the specimens over a solid angle of about 0.26 sr is collected and guided to a monochromator.
ESR Study of X-Irradiated Sr(NO3)2
Authors: Tagaya Kimihito
Published: November 2005

A single crystal of Sr(NO3)2 was irradiated with X-rays at room temperature, and ESR measurements were performed over the temperature range from 85 K to room temperature. It was concluded that besides O-
2, O-
3 and NO2 centers, an F-center was produced, in which an electron was trapped by an NO-
3 vacancy. The orientation of the F-center in the Sr(NO3)2 crystal was determined from the symmetry axis of the g tensor. The sites and orientations of the O-
2,O-
3 and NO2 centers were also determined. The superhyperfine interactions of the F-center with surrounding 14N nuclei of NO-
3 were investigated, and the superhyperfine splitting constants were determined.
Structure Change of Microcrystalline Silicon Films in Deposition Process
Authors: Imura Takeshi , Kaya Hiroshi , Terauchi Hitoshi , Kiyono Hideki , Hiraki Akio , Ichihara Masaki
Published: November 2005

Structure change with thickness of films of microcrystalline silicon prepared by reactive sputtering and glow discharge techniques has been investigated with transmission electron microscopes and a Fourier transform infrared spectrophotometer. An amorphous state changes into a microcrystalline one with increase of the thickness from 10 to 100 nm. Sufficiently thick films (>0.4∼0.5 µm) deposited by the reactive sputtering show a columnar structure with an orientation of microcrystals {110} parallel to the substrate. As the orientation of the microcrystals develops with thickness, IR absorption bands due to Si–H stretching become sharper.
Effect of Quenching Immediately after Sputtering on Superconducting NbN Films
Authors: Akune Tadahiro , Sakamoto Nobuyoshi , Shibuya Yoshio
Published: November 2005

In order to stabilize the metastable NaCl structure (the δ phase) of NbN at low temperatures, NbN films sputtered on sapphire substrates were thermally quenched immediately after deposition by thermal conduction from a water-or liq. N2-cooled anode container, or by direct spraying of liq. N2 onto the as-sputtered film. When the cooling rate Q

r
was increased, the superconducting transition temperature T

c
and the resistance ratio β(=R
300K/R
20K) changed from a slightly downward trend to an upward one near Q

r
=104°C/min. Above this value of Q

r
, X-ray analysis indicated that the growth of the δ phase was enhanced, while that of the ε phase was depressed. The broad transition width Δ
T

c
which appeared at a value of Q

r
between 2×103 and 104°C/min is considered to be closely related to the coexistence of the δ and ε phases.
Perpendicular Magnetic Anisotropy of TbCo Films
Authors: Yoshino Seiji , Takagi Hiroshi , Tsunashima Shigeru , Masuda Morio , Uchiyama Susumu
Published: November 2005

An experimental study has been made on the magnetic anisotropy of amorphous TbCo films prepared by rf co-sputtering. TbCo films prepared at a substrate bias voltage of –100 V exhibit a large uniaxial anisotropy of 2×106 erg/cm3 with its easy axis perpendicular to the film plane, whereas films prepared without the substrate bias exhibit the anisotropy with its easy axis in the film plane. The planar stress due to the substrate constraint considerably influences the perpendicular anisotropy through the large magnetostriction of about 2×10-4. When films with perpendicular anisotropy are removed from the substrate, the anisotropy energy decreases to 65–80 percent of its initial value. Annealing for one hour at 300°C destroys the perpendicular anisotropy almost completely.
Defects in Neutron-Transmutation-Doped Germanium
Authors: Fukuoka Noboru , Saito Haruo
Published: November 2005

The nature of the defects produced in arsenic- or antimony-doped germanium by the recoil energy associated with capture gamma-ray emission after thermal neutron absorption was studied by measuring the Hall coefficient and the DLTS spectrum.
It was concluded that the defects produced by thermal neutron irradiation are removed by annealing for 20 min at 600 K. Electron trapping levels located at E
c-0.20 eV, E
c-0.22 eV, E
c-0.27 eV and E
c-0.40 eV are formed after irradiation with thermal neutrons. The defect associated with the E
c-0.22 eV level is considered to contain an interstitial arsenic atom.
Optical Observation of Inhomogeneity of Chromium-Doped Semi-Insulating GaAs
Authors: Kitahara Kuninori , Ozeki Masashi , Shibatomi Akihiro
Published: November 2005

The macro- and micro-scale inhomogeneity of semi-insulating GaAs grown by the liquid-encapsulated Czochralski (LEC) method was investigated using three kinds of optical scanning measurement: near-band-edge luminescence, intrinsic photocurrent, and near-infrared photoabsorption. The photoabsorption measurement was used to obtain the distribution of Cr. The correlation found between the luminescence and photocurrent profiles implies that the defect center density is relatively small in the high dislocation density region. The low correlation between the photoabsorption and luminescence profiles indicates that the distribution of Cr is not dominated by dislocations. The possibility of interaction between dislocations and defects in LEC-GaAs was studied by carrying out a heat treatment experiment.
Temporal Behaviour of ECR Plasmas Produced by a Lisitano Coil
Authors: Suetsugu Yusuke , Kawai Yoshinobu
Published: November 2005

In order to clarify the mechanism of production of a plasma produced by electron cyclotron resonance heating (ECRH) using a Lisitano coil, the temporal behaviour of the plasma was measured in detail by a sampling method. It was found that the plasma is produced not only around the Lisitano coil but also near the center. The plasma density was also confirmed to attain a value above the cutoff density by measuring the field intensities of the microwaves.
Photochromic Coloration Enhancement for Rare Earth Orthoniobates
Authors: Suemune Yasutaka
Published: November 2005

An attempt to improve photochromic coloration of LaNbO4, GdNbO4 and YbNbO4 has been made by doping with several kinds of impurities. These include praseodymium in the rare earth group, calcium, strontium or barium in the IIa group, and germanium or tin in the IVb group. The divalent IIa group ions and the quadrivalent IVb group ions are considered to reduce partially the host trivalent rare earth ions into the divalent ions and incidentally to produce a corresponding amount of oxygen vacancies. In fact, doping of each dopant has been shown to heighten the photochromic characteristics of the three compounds mentioned above. Furthermore, multiple doping of praseodymium and the other impurities has been found to be markedly effective also in regard to these compounds. Codoped impurities of certain optimum amounts lead to realization of very high level photochromic characteristics.
A Highly-Sensitive Dry Developable Resist
Authors: Tsuda Minoru , Oikawa Setsuko , Yabuta Mitsuo , Yokota Akira , Nakane Hisashi
Published: November 2005

A highly-sensitive dry developable resist for a deep UV aligner is described. The exposure time required is 1–2 sec, and the resist thickness remaining after dry development is 80–90%. The mechanism giving the high sensitivity was elucidated theoretically.
High Rate Preparation of a-Si:H by Reactive Evaporation Method
Authors: Shindo Masanari , Sato Shigeru , Myokan Isao , Mano Shigeru , Shibata Takuji
Published: November 2005

A high rate deposition method of a-Si: H based on reactive evaporation is described. a-Si: H prepared at a deposition rate of 30 Å/sec has much the same photoconductivity as films prepared by the glow discharge (GD) method. It is revealed that silicon oxidation due to residual oxygen gas is suppressed using a method of silicon evaporation to supply hydrogen ions. H2
+ is essentially a dominant species. Dark conductivity of a-Si:H decreases monotonically with increasing hydrogen content.
Formation Kinetics of Niobium and Molybdenum Silicides Induced by Ion Bombardment
Authors: Kanayama Toshihiko , Tanoue Hisao , Tsurushima Toshio
Published: November 2005

Kinetics of silicide formation induced by ion bombardment was investigated in Nb-deposited-on-Si (Nb/Si) and Mo/Si systems by using a backscattering technique in order to elucidate formation mechanisms. The kinetics was observed to be different in these systems. In Mo/Si, the amount of Si atoms intermixed into the silicide is proportional to (dose)1/2 and independent of the properties of the Si substrate; in Nb/Si, it is proportional to the nuclear energy deposition by the ion at the silicide/Si interface and is affected depending on whether the substrate is amorphous or crystalline. From these results and the temperature dependence observed, it is concluded that defects produced by the ion cause the silicide growth by inducing the reaction at the silicide/Si interface and atomic diffusion in the silicide layer; in Nb/Si the former process is rate limited and in Mo/Si it is the latter.
Mössbauer Studies of Very Thin Oxide Layer on Fe Surface
Authors: Shinjo Teruya , Iwasaki Takashi , Shigematsu Toshihiko , Takada Toshio
Published: November 2005

Very thin oxide layers on Fe metal surfaces with the thickness of ca. 10 Å, are investigated by means of Mössbauer absorption spectroscopy using surface-selectively enriched samples. The oxide is similar to γ-Fe2O3 but has non-collinear spin arrangement at 4.2 K and is superparamagnetic at 300 K. The reduction of the recoilless fraction at 300 K is not drastic. Oxidation of Fe surfaces coated by Sb layers is also studied.
Energy Spectra of Thermally Stimulated Exoelectrons from KCl:Tl X-Irradiated at 77 K
Authors: Kamada Masao , Yoshihara Kiichi , Tsutsumi Kenjiro
Published: November 2005

Simultaneous measurements of the energy spectra of thermally stimulated exoelectrons and of the surface potential are carried out on KCl:Tl X-irradiated at 77 K. It is found that high energetic exoelectrons are emitted when the sample surface is charged up positive and that the width of their energy spectra is larger than the non-uniform spread of the surface potential (patch field). These results suggest that the energy spectra of the thermally stimulated exoelectrons from KCl:Tl may be interpreted using a space charge model, in which the exoelectrons are accelerated by the internal electric field and are scattered by the optical modes of lattice vibrations during the transport of the exoelectrons to the surface, although the patch field effect also is thought to contribute to the energy spectra of the exoelectrons.
Transient Photodischarge Characteristics of Photoconductors with Dispersive Transport
Authors: Naito Hiroyoshi , Motomura Kohta , Okuda Masahiro , Nakau Tanehiro , Matsushita Tatsuhiko
Published: November 2005

The transient photodischarge characteristics in a photoconductor displaying dispersive transport under an open-circuit condition are analyzed numerically. The transport parameters obtained from the present configuration are equivalent to those of a constant-voltage configuration within the small-signal limit. It is shown that, with increasing amounts of charge in transit, the post-transit-time slope of a double-logarithmic |dV(t)/dt| vs time plot increases algebraically, with the pre-transit slope and transit time being largely unaffected. Investigations of the effect of pre-existing trapped space charge indicate that the pre-transit slope depends upon the amount of this space charge. The results point the way to the use of the characteristics for determining transport parameters in a practical xerographic system.
Electron Irradiation Damage in Radiation-Resistant InP Solar Cells
Authors: Yamaguchi Masafumi , Uemura Chikao , Yamamoto Akio , Shibukawa Atsushi
Published: November 2005

In this paper it is shown that InP solar cell is more radiation-resistant than Si and GaAs solar cells.
1 MeV electron irradiation damages in InP solar cells with AM 1.5 conversion efficiencies exceeding 16.5% are examined. Minority carrier diffusion length and carrier concentration studies for defects induced by 1 MeV electron irradiation in InP solar cells are carried out, and the correlation between the measured defect parameters and the performance characteristics of the electron-irradiated InP solar cells are elucidated. InP solar cells with higher carrier concentration substrate are found to be more radiation resistant, which is due to the superior radiation-resistance for the high carrier concentration InP substrate.
Studies of Photoluminescence Intensity in the InP/InGaAsP/InP Double Heterostructure
Authors: Komiya Satoshi , Yamaguchi Akio , Umebu Itsuo , Kotani Tsuyoshi
Published: November 2005

Photoluminescence intensity and spectrum of the InGaAsP layer in the double heterostructure with either n-InP/n-InGaAsP or p-InP/n-InGaAsP are investigated over a wide range of excitation power density 10-1–104 Wcm-2 by using a Nd:YAG laser with a wavelength of 1.064 µm transparent to the top InP layer. From analysis of photoluminescence intensity, an interface recombination velocity smaller than 2.5 cm s-1 is estimated. It is found from photoluminescence spectra that carrier temperature becomes higher than lattice temperature at high excitations. The excitation power dependence of photoluminescence intensity of samples with a p-n junction differs from that of samples with an n-n junction. The former shows a low internal quantum efficiency at low excitations and subsequent rapid recovery with increasing excitation power, while the latter shows a linear dependence of photoluminescence intensity over a wide excitation range.
Properties of GaAs/Al0.53Ga0.47As Avalanche Photodiode with Superlattice Fabricated by Molecular Beam Epitaxy
Authors: Susa Nobuhiko , Okamoto Hiroshi
Published: November 2005

A GaAs/AlGaAs APD with superlattice, exhibiting low dark current and large photocurrent multiplication characteristics, has been successfully fabricated by MBE. Dark currents were as low as 2.1×10-6 A/cm2 for a multiplication factor of 30. A study of the influence of oval defects on APD characteristics showed that no one-to-one correlation was found between oval defects and fatal diode deterioration. The ionization rate ratio, β/α, estimated from multiplication noise measurement, was less than 0.6–0.8. MBE is a useful technique for fabricating high performance APDs.
Contactless Measurement of Short Carrier Lifetime in Heat-Treated N-Type Silicon
Authors: Yamazaki Tatsuya , Ogita Yoh-ichiro , Ikegami Yoshikazu , Onaka Hiroshi , Ohta Eiji , Sakata Makoto
Published: November 2005

Sub-microsecond excess carrier lifetimes have been measured by a contactless method and the electrical properties have been investigated by the isothermal capacitance method in heat-treated N-type silicon. It is found that the thermally induced donor level at E

v
+0.39 eV acts as recombination center. By using the present contactless measurement system, it becomes possible to accurately measure lifetimes as short as 0.07 µsec, and resistivity-lifetime products, ρτ=0.1 Ωcm · µsec, have been achieved.