bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropic Thermal Diffusion of PVDF Film
Authors: Okamoto Shinobu , Hatanaka Yoshinori
Published: March 2014

Anisotropic thermal diffusion of polyvinylidene fluoride was calculated in two dimensional analysis and compared to the experimental results. The transient pyroelectric currents due to the lateral heat diffusion in the film were measured when the laser light was projected. Thermal diffusivity in the direction parallel to the stretched direction, k//, was about three times lager than those to the perpendicular direction, k⊥. The k// and k⊥ were about 4.5×10-3cm2 sec-1 and 1.5×10-3, respectively. It was found in calculation and experiments in the pyroelectric vidicon that the spreading of spot images in the stretched direction are about two times larger than that in the perpendicular direction.
Thin Film Preparation of Superconducting Perovskite-Type Oxides by rf Sputtering
Authors: Suzuki Minoru , Enomoto Youichi , Murakami Toshiaki , Inamura Takahiro
Published: March 2014

Superconducting thin films of perovskite-type oxide of BaPb1-x
Bi
x
O3 (x=0.2, 0.25, 0.3, 0.4) and Ba0.95Sr0.05 Pb0.75Bi0.25O3 were prepared by rf sputtering with their superconducting transition onsets of about 8 K. The films tended to lack Pb and Bi and this tendency could be reduced by sputtering under sufficiently high oxygen partial pressure. The transition temperature becomes reduced in both cases of low (x=0.2) and high (x=0.4) Bi content. The strontium substitution aiming at sharp transitions was not so effective as in the bulk materials and resulted in high resistive thin films.
A New-Structure LiTaO3 Pyroelectric Infrared Detector
Authors: Nakano Shoichi , Kishi Yasuo , Yokoo Toshiaki , Shibata Kenichi , Kuwano Yukinori
Published: March 2014

A LiTaO3 pyroelectric infrared detector with a new type of structure has been developed.
The detective material is supported on an electric conductor by a special adhesive which possesses high electricel conductivity and low thermal conductivity.
The pyroelectric responsivity and D* of this new-type pyroelectric detector are calculated theoretically as a function of the thickness of the pyroelectric element, and the thickness dependence of the responsivity and D* are experimentally confirmed. The theoretical calculation has been shown to be in agreement with experimental results.
Growth and SAW Properties of (Ba2-xSrx)TiSi2O8 Crystals
Authors: Ito Yukio , Nagatsuma Kazuyuki , Ashida Sakichi
Published: March 2014

Part of the phase diagram of a (Ba2-x
Sr
x
)TiSi2O8 system is demonstrated and then (Ba2-x
Sr
x
)TiSi2O8 (x≤1.0) single crystals are grown by the Czochralski (CZ) technique and the edge-defined film-fed growth (EFG) technique. The crystal composition, particularly the Sr concentration, of a CZ grown crystal varies according to the normal freezing distribution. The Sr concentration of an EFG grown crystal is almost constant. The excellent SAW properties; low temperature coefficients of delay and high electromechanical coupling factors of the grown crystals are also described.
Fracture Mechanics Evaluation of Fracture Strength of Ferroelectric Ceramics
Authors: Niitsuma Hiroaki , Tanaka Tohru , Chubachi Noriyoshi , Sato Risaburo
Published: March 2014

A fracture mecahnics approach to evaluate a fracture strength of commercially available piezoelectric ceramics is described. Relationship between nominal fracture toughness k
Q and square root of crack tip is represented by two straight lines, and the fracture toughness K
IC can be determined by using the specimen with a notch root radius which is smaller than the maximum pore radius in the ceramic. A new parameter, T
IC, which is estimated by the fracture toughness test and SEM observation of the largest pore size, provides a representative fracture strength as a material constant of the ceramics.
Growth Conditions and Their Effects on Growth Features of Pb(Zr-Ti)O3 Single Crystals
Authors: Tsuzuki Kaoru
Published: March 2014

Growth conditions,.growth parameters and their effects on growth features of Pb(Zr-Ti)O3 single crystals were examined using high-temperature 40KF-56PbF2-4Pb3(PO4)2 solution as a flux. Crystal habit, size and quality are sensitive to both growth conditions and parameters. Desirable crystals are grown from raw material rich solutions using a temperature gradient which the bottom of the crucible is hotter than the top, during cooling.
Electrical and Optical Properties of Ferroelectric Smectic Liquid Crystal and Their Application III
Authors: Yoshino Katsumi , Uemoto Tsutomu , Urabe Takashi , Inuishi Yoshio
Published: March 2014

Ferroelectricity in the smectic-C phase of two series of compounds (L-DOBACPC series and D-DOBAMBC series) are studied and discussed in terms of their molecular structures. Bistable memory effect in the smectic-C phase and an electro-optical effect in the smectic-H phase are studied.
Application of (Pb, Nd)(Ti, Mn, In)O3 Piezoelectric Ceramics to High Frequency SAW Filters
Authors: Nagatsuma Kazuyuki , Jyomura Shigeru , Onozato Harumasa , Takeuchi Hiroshi
Published: March 2014

High frequency (250∼650 MHz) SAW filters have been fabricated using (Pb, Nd)(Ti, Mn, In)O3 piezoelectric ceramics with a fine grain size less than 1 µm. These ceramics shows the lowest SAW propagation losses that have been reported for piezoelectric ceramics such as Pb(Ti, Zr)O3 ceramics. The fabricated filters shows a good bandpass response of about 20 dB insertion loss and 25 dB out-of-band rejection. This indicates that these ceramics have high potential for use as materials in high frequency SAW applications.
Second Harmonics Generation from Transparant PLLZT Ceramics Excited by a Q-Switched Nd3+ Glass Laser
Authors: Jyumonji Masanori , Kasai Kiyokazu , Masuda Yoichiro
Published: March 2014

Nonlinear optical characteristics of transparent PLLZT ceramics have been examined. The ceramic samples have been prepared by various hot-pressing temperatures, pressures and soaking times, and optimum fabrication condition has been experimentally decided by the density, average grain diameter and optical transmittance measurements.
An intense SHG light was observed for the first time on PLLZT ceramics when the ceramics were pumped by a Q-switched high repetition rate Nd3+ glass laser light. A conversion efficiency was about 0.17% at 13 MW pump power.
Electrical and Optical Properties of Hot-Pressed AαNb2(3-α)/5O3-PbZrO3-PbTiO3 (A= Ba, Sr) Ceramics
Authors: Miura Shinsuke , Yokosuka Masaru , Ochiai Tsutomu , Marutake Masakazu
Published: March 2014

A new electrooptic ceramic (Pb1-x
Aαx
) {Nb2(3-α)x/5(Zr
y
Ti1-y
)1-x
}O3 is proposed, where A=Ba or Sr. These ceramics sintered by the conventional hot-pressing method exhibit excellent optical chracteristics; namely their transmittances and transverse linear electrooptic coefficients being comparable to those of PLZT.
Compositional and/or temperature dependences of dielectric constants, electromechanical coupling factors and lattice parameters have been measureed to elucidate the phase bondaries of these systems.
It is also shown that lattice bacancies in the Pb sites deteriorate optical transparency considerably.
A New Electrooptic Light Deflection Phenomenon
Authors: Watanabe Takaya
Published: March 2014

A new electrooptic light deflection phenomenon has been investigated. This is presumably due to the spatial distribution in the refractive index, induced by the nonuniform electric field under the surface electrodes. 100% deflection efficiency is attained and a large deflection angle can be provided at low driving voltage, either AC or DC. This phenomenon was observed in various materials, including crystals and glasses.
(Invited) Recent Advances in Photoluminescence Analysis of Si: Application to an Epitaxial Layer and Nitrogen in Si
Authors: Tajima Michio
Published: March 2014

The photoluminescence (PL) technique has been applied for the first time to the characterization of shallow impurities in Si epitaxial crystals and of nitrogen in bulk Si crystals. The species of impurities incorporated intentionally or unintentionally in an epitaxial layer can be definitely determined by the PL analysis. The new PL line at 1.1223±0.0001 eV observed in N-doped crystals is identified to be due to nitrogen. Epitaxial samples show a quantitative relationship between the intensity ratio of the PL line from an epitaxial layer to that from its substrate and the impurity concentration in the epitaxial layer. In N-doped crystals, the PL intensity ratio between the intrinsic and the 1.1223 eV lines increases linearly with the N concentration. It is demonstrated that these PL intensity ratios can be used as measures of the respective impurity concentrations.
Deep Levels Induced in Annealed CZ Silicon
Authors: Ikeda Kousuke , Takaoka Hidetoshi
Published: March 2014

The effect of crystalline defects induced in annealed p-type CZ silicon on deep levels has been investigated by transmission electron microscopy and deep level transient spectroscopy. The majority carrier traps, located at E
v+0.47, E
v+ 0.55 and E
v+0.63 eV, have been found in Schottky diodes which contained oxide precipitates (∼1011 cm-3), dislocation loops (∼1010 cm-3) and stacking faults (3×109 cm-3), respectively. These trap densities are about 1015 cm-3. To explain the difference between defect density and trap density, these levels are ascribed to the defect strain. A simple defect strain model is proposed.
(Invited) The Potential for Bipolar VLSIs
Authors: Nagata Minoru , Okada Yutaka
Published: March 2014

The possibility of using bipolar devices for high density VLSIs is discussed. Fundamental limitations involving the integration level, speed, power and packaging condition are stated. It is pointed out that the main difference between MOS and bipolar devices is the difference in switching energy. Bipolar devices' high transconductance at low operating voltages, resulting from strong non-linearity, is the key in surpassing MOS devices. The potential for I2L circuits in high speed, dense VLSIs is discussed. It is shown by computer simulation that a switching speed of 150 ps seems to be possible for submicron scaled I2Ls. Also an 80 k-gate VLSI with t
pd=1.5 ns will be feasible with bipolar devices. An VLSI with such a construction can compete favorably with MOS VLSIs in density and performance.
(Invited) Chemical Amplification in Biosensors
Authors: Aizawa Masuo , Suzuki Shuichi
Published: March 2014

Two novel biosensors, non-labeling and labeling immunosensors, have been developed by unique combination of solid-phase (membrane-bound) antibody with electrochemical sensing devices. Both immunosensors showed excellent selectivity due to immunochemical specific affinity of membrane-bound antibody to the corresponding antigen. A non-labeling immunosensor was designed for the determination of antigen by measuring transmembrane potential across an antibody-bound membrane. A labeling immunosensor was facilitated with chemical amplification of labeling enzyme along with an antibody-bound membrane. Calibration curves were obtained for human serum albumin in the range 10-5–10-3 g/ml and 10-8–10-5 g/ml with the non-labeling and labeling immunosensors, respectively. Practical importance of chemical amplification is discussed in relation to biomedical sensing systems.
Platinum Silicide Schottky-Barrier IR-CCD Image Sensors
Authors: Kimata Masafumi , Denda Masahiko , Fukumoto Takaaki , Tsubouchi Natsuro , Uematsu Shigeyuki , Shibata Hiroshi , Higuchi Takaichi , Saheki Toshikazu , Tsunoda Reikichi , Kanno Toshio
Published: March 2014

A 64 × 32-element Si monolithic IR-CCD array with the improved PtSi/p-Si Schottky-Barrier (S.B.) detectors has been developed. The improvement of the photoyield was achieved by the structure with no interconnection metal over the detectors and the thinner PtSi film for the S.B. The physical mechanism of the higher photoyield is discussed taking into account the carrier reflection at interfaces (PtSi–Si and PtSi–SiN). The performance of the 64 × 32 IR-CCD was sufficient enough to obtain a thermal image in the 3 to 5 µm atmospheric window range.
Quasi-Three-Dimensional Approach to Transient Analysis of I2L Devices
Authors: Hanihara Koji , Kamiya Takeshi , Yanai Hisayoshi
Published: March 2014

Quasi-Three-Dimensional modeling, where a device is represented by several one-dimensional model units and the network which connects them, is extended to the transient analysis of I2L devices. Even at high current levels good agreement between the computed delay time and the measured one is obtained. Moreover, we establish quantitatively the effect of lateral voltage drops on the delay time.
Fabrication and Properties of High-Current-Density Nb Josephson Junctions
Authors: Yamanaka Toshiaki , Goto Toshinari
Published: March 2014

Nb-NbO
x
-Pb Josephson junctions operable at high current density were fabricated and their electrical properties were investigated. The critical current density ranging from 30 to 6×105 A/cm2 was obtained with thermally oxidized barrier of which area was reduced down to 4×10-8 cm2 by employing photolithography and anodic oxidation of niobium film. From the quasi-particle characteristics and the magnetic dependence of maximum Josephson current, it was found that the tunneling current was dominant in such a barrier and the barrier was quite uniform in spite of thinness. These would be applicable to high-speed computer elements.
(Invited) Improved Avalanche Photodiodes for Long Wavelength Optical Fiber Systems
Authors: Kimura Tatsuya , Kanbe Hiroshi
Published: March 2014

This paper reviens Ge-APDs and InGaAs/InP-APDs with improved properties for long wavelength fiber systems. Ge-APDs with p+-n and n+-n-p junction structures have lower multiplication noise in the wavelength region of 1–1.55 µm than that of a conventional n+-p structure Ge-APD.
InGaAs/InP-APDs with separated absorption and multiplication regions have lower dark current and lower multiplication noise in the 1–1.6 µm wavelength region than those of Ge-APDs. This APD has a capability to improve the minimum detectable power by 3–4 dB, compared with Ge-APD.
Buried Multi-Heterostructure (BMH) GaAlAs Laser
Authors: Okajima Masaki , Kurihara Haruki , Iida Seiji , Watanabe Yukio , Motegi Nawoto
Published: March 2014

Buried multi-heterostructure (BMH) laser, which has a symmetric separate confinement heterostructure, has been developed. Due to the structure, stable fundamental mode oscillation and nearly symmetric and narrow beam divergences of 21° and 25° (FWHM) parallel and perpendicular to the junction plane, respectively, were obtained. Available output power under cw operation was 15 mW without facet coating and 30 mW with Al2O3 coating. For lateral current confinement, a current blocking pn junction and a self-aligned anodic oxide insulating layer were studied. The latter provided a more reliable device process. With the structure, threshold currents as low as 15 mA were obtained for 2 µm-wide stripe and 280 µm-long cavity. For the second LPE growth mask, a Ga0.4Al0.6As epilayer was used, while dielectric masks, such as SiO2 and SiO3N4, were found to react with Al in the Ga melt.
Bistability and Differential Gain in Semiconductor Lasers
Authors: Kawaguchi Hitoshi
Published: March 2014

Bistable operation and differential gain characteristic have been achieved in the current-light output characteristics for stripe geometry InGaAsP/InP DH lasers with an inhomogeneous excitation. This device has an advantage in that the characteristics can be chosen merely by varying the stripe geometry and tuning the device temperature.
Under the operating condition of bistability, switching between the two states was accomplished by applying an electrical pulse of 2.5 mA or less to the device. Switch-on time was less than 0.5 ns and switch-off time was about 1 ns.
Bistable operation by optical injection is also reported. An incident optical beam, generated by a conventional DH semiconductor laser, was injected into the bistable laser. Bistability has been achieved in incident beam intensity-optical output intensity curves. The bistable laser also acted as an optical limiter.
SOS CMOS 16 Bit Parallel Multiplier
Authors: Fukuma Masao , Ohno Yasuo , Okuto Yuji
Published: March 2014

A high performance 16 by 16 bit parallel multiplier is presented, which features SOS CMOS configuration. Maximum multiplying time and average power are 65 ns and 250 mW (VDD=5 V), respectively. The SOS CMOS multiplier shows the best powerdelay product, compared with other device-configuration multipliers reported. This performance can be accurately reproduced by circuit simulation without including parasitic capacitance. Through this experimental study, the SOS CMOS advantage for logic LSI application was confirmed.
A Low Power 8 Bit Parallel A/D Converter with High Accuracy Process
Authors: Takemoto Toyoki , Inoue Michihiro , Sadamatsu Hideaki , Matsuzawa Akira , Komeda Tadao
Published: March 2014

A high accuracy process offering small ΔV
BE of pair transistors, small contact resistance, and uniform reference resistance, has been applied in the design of an 8 bit parallel 40 MHz A/D converter.
A new bipolar structure produced by serial implantation of B+ and Ass
+ through the same opening window of SiO2 has been developed to realize high speed and high uniformity.
An optimized high speed comparator stage was developed in which the number of transistors and power consumption were reduced.
Consequently, an 800 mW, 40 MHz sampling frequency, 8 bit A/D converter was developed.
Dependence of Channel Hot-Electron Injection on MOSFET Structure
Authors: Kume Hitoshi , Takeda Eiji , Toyabe Toru , Asai Shojiro
Published: March 2014

The dependence of channel hot-electron injection upon MOSFET structures is reported. Hot-electron injection, which is a serious constraint for MOSFETs scaled down to the 1 µm level, is directly evaluated by measuring gate current to as low as the order of 10-15 A. The measured gate current is modeled numerically, based on a thermionic emission equation for heated electron gas.
In order to minimize hot-electron injection, three device structures are proposed: a graded drain structure; an offset gate structure; and a buried channel structure. The proposed device structures improve the highest applicable voltage, as limited by hot-electron injection, by as much as 1–2 V.
Novel Gate Structure for High Voltage Light-Triggered Thyristor
Authors: Ohashi Hiromichi , Tsukakoshi Tsuneo , Ogura Tsuneo , Yamaguchi Yoshihiro
Published: March 2014

This paper presents a novel gate structure for a high power light-triggered thyristor, which is easily fired with a light-triggering system consisting of a commercially available LED and optical fibers. The key features of the novel gate structure are its light sensitive area surface consisting of a central P-base portion, and its surrounding stepwise deep diffused N-emitter with more than 70% to 75% quantum efficiency.
A 4 kV-1.5 kA directly light-triggered thyristor was developed using the novel gate structure as a first pilot thyristor for a newly developed multi-stage amplifying gate, satisfying excellent overall characteristics of 2.5 mW minimum light triggering power, 250 A/µs di/dt capability and 1.5 kV/µs dv/dt capability, as well as high voltage turn-on testing from 4 kV rated full blocking voltage without di/dt failure.
Characteristics of Silicon Inversion Layer Solar Cells
Authors: Matsuura Hideharu , Fujii Hisao , Takai Hitoshi , Matsunami Hiroyuki
Published: March 2014

Fundamental characteristics of silicon inversion layer (IL) solar cells using SiO/Si as an active region and Mg/SiO2/Si as an MIS junction are studied. Methods to estimate the degree of inversion at the Si surface of the cells are established. The degree of inversion gives significant effects on energy conversion efficiency. The optimum preparation condition of the SiO film which makes inversion at the Si surface is investigated to make inversion stronger. In order to decrease the sheet resistance and to optimize the thickness of the insulator for MIS junctions, effects of thermal oxidation of the Si surface is studied. Photovoltaic properties of the Si IL solar cells with different resistivities are measured. The AM 1 efficiency of 13.5% was obtained.
Si Solar Cells Fabricated by Ion Implantation and Short Time Furnace Processing
Authors: Usami Akira , Takebayashi Koji
Published: March 2014

A method for silicon solar cell fabrication is being developed around ion implantation and short time furnace annealing techniques. Low temperature and short time furnace annealing process is effective for high efficiency solar cell. As the result of the novel annealing techniques, major reductions in annealing process cost is expected. Solar cells fabricated by P+ implantation and 800°C annealing for 3 min showed a conversion efficiency of 10% without AR coating and BSF structures.
Bus Electrode Having Same Thermal Expansion Coefficient as Crystalline Silicon Solar Cell
Authors: Kato Taketoshi , Inomata Koichiro , Morita Hiroshi , Mori Fumio , Nakano Hirotaka , Sugai Shinzo , Washida Hiroshi , Onoe Akira
Published: March 2014

It is well known that bus electrode plays a main role in series resistance of solar cells. Bus electrodes composed of the bare leads, of which thermal expansion coefficients are less than cell's, coated with highly conducting metals were investigated. These leads exhibited the lower expansion coefficient than expected by the empirical law, and the origins of these phenomena were explained. Work hardening effect on expansion coefficient was then measured.
Solar cell fabrication with these leads and rigid solders rationalized assembly processing. Cell characteristics proved to be excellent compared with conventional ones. Finally, lead costs were compared for various materials.
Titanium Dioxide Antireflective Coating for Silicon Solar Cells by Spinning Technique
Authors: Murozono Mikio , Kitamura Sotoyuki , Ohmura Takuichi , Kusao Kenji , Umeo Yoshiyuki
Published: March 2014

Optimum TiO2 antireflective (AR) films for silicon solar cells are obtained by coating the solution prepared from organotitanium compounds, acetylaceton as a ligand, and ethanol as a solvent on the silicon surface by spinning technique and then by firing them under a high temperature after baking.
Using the same conditions for the heat treatment, the thickness of AR films can be controlled easily up to 1200 Å by changing solution concentration and spin speed. The optical properties of AR films, moreover, depend on the heat treatment conditions.
Optimized AR films on silicon solar cells are obtained by coating an ethanol solution having a 4% equivalent TiO2 concentration on the silicon surface at a spin speed of 4000 rpm and by firing them at 80°C in the presence of oxygen after baking. The refractive index and thickness of AR films obtained under above coating are 2.4 and 620 Å, respectively. Silicon solar cells with these AR films show as much as a 50% improvement in conversion efficiency over uncoated cells.
GaAs Solar Cell Test Facility
Authors: Kawashima Maumi , Hosoda Yoshikado , Suzawa Chizuru , Shimada Toshiro , Motoyoshi Kenya , Sasatani Yukihiro
Published: March 2014

A hybrid type (electricity and heat) GaAs solar cell test facility has been made to evaluate total characteristics of GaAs cell and to study the energy conversion system.
The size of solar collector is 3.4 m ×2.1 m and 60 GaAs cells with Fresnel lenses are attached on it. The solar collector is controlled by a microcomputer to track up the sun. Electric energy produced by the cells is stored in a lead-acid battery and then supplied to the load through a DC-AC inverter. The microcomputer also controls the data acquisition in parallel with tracking.
This paper presents an overview of our facility and experimental results of power generation obtained to date.
Substitutional Doping of a-SixNi1-x: H
Authors: Kurata Hiroyuki , Miyamoto Hironobu , Hirose Masataka , Osaka Yukio
Published: March 2014

Substitutional doping of a-Si
x
Ni1-x
: H and the structural properties have been systematically investigated. Valency control of a-Si
x
N1-x
: H is found to be possible, although the efficiency of phosphorus doping is rather low with respect to that of boron doping. Vibrational spectra of boron-doped films showed the presence of a considerable amount of the BN bonds, which reduces the amount of the SiN bonds in the network, while phosphorus-doped films contain no PN bonds. Excellent thermal stability of undoped a-Si
x
N1-x
: H and the absence of photostructural change are also confirmed.
Junction Properties of nip and pin Amorphous Si Solar Cells Prepared by a Glow Discharge in Pure Silane
Authors: Taniguchi Hitoshi , Konagai Makoto , Lim Koeng Su , Sichanugrist Porponth , Komori Koichiro , Takahashi Kiyoshi
Published: March 2014

The junction properties of various a·Si solar cell structures have been studied in some detail. Various structures of a·Si solar cells such as pin, nip, pp-n, and nn-p structures were prepared. The nip solar cell gave a conversion efficiency of 6.86% under AMI (100 mW/cm2) insolation through its n-layer. It is demonstrated experimentally and theoretically that the opto-electronic properties of the undoped layers of a·Si solar cells were influenced by residual impurities. The nip cell is shown to be of an np-p or np-p structure because of the residual boron during the deposition process, and gives a higher conversion efficiency under illumination through its n-layer than through the p-layer. The current transport mechanism is shown to depend on the electrical properties of the central (normally undoped) region. Doping the central region with boron causes a decrease in the injection current component into p-layer, and hence an increase in the n-value and the open-circuit voltage.
A New Model for Simulating Photocarrier Collection in Amorphous Silicon Solar Cells
Authors: Nonomura Shuichi , Okamoto Hiroaki , Kida Hirotsugu , Hamakawa Yoshihiro
Published: March 2014

A new carrier transport model describing the characteristic features of the photovoltaic property in a-Si solar cells has been developed, where transport of both electrons and holes is taken into consideration. Based upon this model, collection efficiency spectra have been theoretically calculated and compared with experimental data to evaluate some basic parameters; mobility lifetime products and effective surface recombination velocities. Through the systematic examinations of thus obtained parameters in various a-Si solar cells, a correlationship between the photovoltaic performance and the cell fabrication conditions has been made clear.
Effects of Substrate Surface Condition on a-Si Photovoltaic Characteristics
Authors: Fukatsu Takeo , Sakai Soichi , Nakayama Shoichiro , Tsuda Shinya , Kuwano Yukinori
Published: March 2014

A morphological study of a-Si film deposited on Al substrates is investigated. The a-Si film grows to form a large “grain” texture as the roughness of the substrate surface increases.
An EBIC image of a-Si deposited on Al substrate becomes bright and uniform as the surface becomes flatter and flatter. The normalized photoconductivity ηµτ, collection efficiency, and photovoltaic characteristics are also investigated. These results show that the properties of a-Si film and the photovoltaic characteristics of a-Si cells depend on the surface condition of the substrate.
Silicon Sheet Casting using a Mold Releasing Agent
Authors: Saito Takeshi , Shimura Akio , Ichikawa Shoji
Published: March 2014

Silicon sheet casting in a SiC coated carbon mold was achieved by using Si3N4 powder as a mold releasing agent. The mold was durable for repeated use more than 30 times. The electrical resistivity within a sheet was relatively uniform and the average polycrystalline grain diameter was 0.6 mm. Solar cells made of this material gave an AMI maximum conversion efficiency of 10.4%.
Effect of Photo-Induced Microcrystallization on Inx(Si0.1 Se0.9)1-x Film-ITO Solar Cells
Authors: Naito Hiroyoshi , Matsushita Tatsuhiko , Suzuki Akio , Okuda Masahiro , Nakau Tanehiro
Published: March 2014

Measurements of electrical and optical properties have been made on amorphous and microcrystalline In
x
(Si0.1Se0.9)1-x
thin films in the composition range from x=0 to 0.5. It is shown how the photovoltaic effect for Au–In
x
(Si0.1Se0.9)1-x
film-ITO structure can be enhanced by the annealing process under illumination. For the system at x=0.1, the power conversion efficiency of 3.53% was obtained at room temperature. This is understood by considering the reduction of the density of gap states.
Photovoltaic Properties of Cuprous Chalcogenide-Silicon Junctions
Authors: Okimura Hiroshi , Togasaki Masami , Iwase Mitsuo , Gekka Yasuo
Published: March 2014

Cu2Te thin films were deposited on glass and n-type Si substrates by vacuum evaporation, and electrical and photovoltaic properties were investigated. Cu2Te thin films show p-type and low resistive conduction, and have carrier density of 1021 cm-3 and Hall mobility of 3–10 cm2/V·sec. Cu2Te–Si junctions have low photovoltaic properties, therefore Cu2Se film was deposited on Cu2Te layer making a structure of Cu2Se–Cu2Te–Si junctions. The maximum solar conversion efficiency of this structure was 9.2% under the sunlight of 83 mW/cm2.
Photoacoustic Spectra in Ternary Semiconducting Compound CdIn2S4
Authors: Yamashita Kouichi , Kasahara Hajime , Yamamoto Keiichi , Abe Kenji
Published: March 2014

The amplitude and phase of the photoacoustic (PA) signal have been studied in ternary semiconducting compound CdIn2S4. By measurements of the phase difference of variable chopping frequency of the incident light on different thickness of samples, thermal conductivity and thermal diffusivity were given to be 1.3×10-2 cal/g·sec·K and 2.3×10-2/sec, respectively. The treatment of sample surface has been also studied: the PA amplitude shows gentle slope with a rough surface layer. The phase difference of the PA signal agreed well with a two-layer model by extending the Rosencwaig and Gersho theory.
Generation Mechanisms of Current-Injection-Induced Acoustic (CIA) Signals in Semiconductor Lasers
Authors: Suemune Ikuo , Nonomura Kazuhiro , Yamanishi Masamichi , Mikoshiba Nobuo
Published: March 2014

Generation mechanisms of current-injection-induced acoustic (CIA) signals in semiconductor lasers are analyzed. It is shown that the CIA signal level is proportional to the power converted into heat in a thin region of the semiconductor laser. The theory is in good agreement with the measurement.
Texture-Induced Acoustic Anisotropy due to Compressive Deformation (Effects of Strain-Rate and Temperature)
Authors: Toda Hiroki , Fukuoka Hidekazu
Published: March 2014

A texture-induced acoustic anisotropy originated by plastic deformation under compression is investigated for copper and aluminum polycrystalline metals making use of a birefringent effect of a polarized ultrasonic wave to study the effects of strain-rate and temperature in the deformation process. A variation in acoustic anisotropy appears to be influenced by both strain-rate and temperature for copper, but it definitely does not appear for aluminum.
Observation of Subsurface Flaws with Scanning Acoustic Microscope
Authors: Yamanaka Kazushi , Enomoto Yuji
Published: March 2014

To establish the effective detection and identification of cracks and precipitations on and under solid surfaces, a comparative study has been made on acoustic micrographs of such flaws using a scanning acoustic microscope. It has been found that different modes of acoustic waves contribute to the detection of different types of flaws.
A Signal Processing for Realization of Ultrasonic Observation System of Sea Flow over a Long Distance
Authors: Okujima Motoyoshi , Ohtsuki Shigeo , Kobayashi Kazumasa
Published: March 2014

The velocity of a current going in and out through a strait can be measured by the differences in underwater sound propagation times with and against the current. A test measuring current velocity was carried out using a trial system which adopted a two-period M-sequence method to reduce the interference of ambient pulsive noises. To realize an easy ultrasonic observation system of sea flow over long distances, we devised a new signal processing system. The results gained by the customary method and by this new technique were compared.
Tuning fork Resonator Using Shear Mode Piezoelectric Ceramic
Authors: Tomikawa Yoshiro , Sakano Shizuo , Oyama Shigeru , Konno Masashi
Published: March 2014

The purpose of the present investigation is to develop a piezoelectric tuning fork resonator with such small capacitance ratio that it can be used as an element of a filter with relatively wide band-width.
The tuning fork resonator proposed in this paper is composed of a shear mode piezoelectric ceramic.
From information obtained in this investigation, it is found that the 2nd mode of the tuning fork is effective in obtaining a small capacitance ratio; however, further research is necessary to develop a means of suppressing unwanted responses.
Low Loss RF Filter Using SAW Resonator
Authors: Ebata Yasuo , Sato Koji
Published: March 2014

A new SAW resonator filter on LiTaO3 (X-112°Y) substrate has been developed. The filter is a transducer coupling 3-poles filter with Butterworth response. It is constructed monolithically and requires no external elements. 3.5 dB minimum insertion loss, 5 10 kHz 3 dB-bandwidth, and 46 dB image signal rejection level are obtained at 280 MHz. This new filter, designed for a front-end filter, enables single super-heterodyne radio paging receivers to be offered.
Studies on the Ultrasonic Vibration Press of Powder –on the Vibration Press with a Vibration Die–
Authors: Tsujino Jiromaru , Ueoka Tetsugi , Aoki Shuichi , Atsumi Yasuhiko
Published: March 2014

An ultrasonic vibration press of hard metal (WC-Co alloy) powder with a 20 kHz longitudinal vibration die is studied. The resonance frequencies of upper and lower punches used are (1) 27 kHz and 20 kHz, and (2) 20 kHz and 20 kHz. The ultrasonic longitudinal vibration die consists of a radial-longitudinal vibration direction converter and 8 bolt-clamped Langevin type PZT transducers. The upper and lower compacting punches are not driven and only the vibration die is driven by a 1 kW power amplifier. It is shown that the ultrasonic vibration of a compacting die is very effective to obtain compacts with higher and more uniform density than without vibration.
Estimation of Echo Signal in Near Field
Authors: Ueda Mitsuhiro
Published: March 2014

The estimation of an echo signal has been successful only for plane and spherical incident waves, but echoes are usually reflected in the near field of an ultrasonic transducer in most ultrasonic pulse echo systems. Recently we proposed a new estimated algorthm for an echo signal which is based on a discrete expression of the medium. This algorithm can be applied to any incident waves if the medium can be assumed as a weakly scattering one. In this paper it is modified for the case of a strong scattering medium and then echoes reflected from a wire of nylon are calculated. The comparison with experiments shows good agreement.
Pulse Ultrasonic Wave in Metal
Authors: Kawashima Katsuhiro
Published: March 2014

Ultrasonic wave field in an elastic medium was quantitatively calculated and measured. Electromagnetic surface force was used as a standard sound source in the experiment. The experimental wave form in time domain was compared with the calculated wave form and excellent agreement was shown but the quantitative difference between the two wave forms was about 40%. A new explanation is given for a pulse wave form split at larger angles.
Measurement of Sound Velocity Change in a Liquid Using a Liquid Delay Line Oscillator
Authors: Toda Kohji , Urabe Heijiro
Published: March 2014

A delay line oscillator for measuring the sound velocity change in a liquid is described. Two interdigital transducers operating at a liquid-solid boundary are used as an input and an output transducer for the liquid delay device. The oscillation frequencies depend upon the elastic property of the liquid. The validity of the operation principle of the measurement is verified experimentally for the sound velocity change in water as functions of temperature and hydrostatic pressure.
Low-Temperature Growth of Piezoelectric AlN Film and its Optical and Acoustical Properties
Authors: Shiosaki Tadashi , Harada Kazushige , Kawabata Akira
Published: March 2014

Piezoelectric AlN films with their c-axis highly oriented normal to the substrate can be grown on sapphire, silicon and glass substrates at a substrate temperature as low as 20°C to 460°C, using reactive rf planar magnetron sputtering of an aluminum target in the Ar+N2 (1:1) atmosphere. The following acoustical and optical properties have been obtained since the last symposium report. The effective SAW coupling factor k2 on the (001) silicon with the IDT located on top of the AlN film is 0.15–0.21% at wavenumber times film thickness (KH) of 0.25–2.0. The TCP of the SAW propagation is -23.9 ppm/°C at KH=1.84.
Change in the characteristics of amorphous As2S3 induced by injected acoustic domains
Authors: Tokunaga Yoshiaki , Morimoto Shozo , Okano Shuichi , Suzuki Masakuni , Hata Tomonobu
Published: March 2014

This paper is concerned with a change in the acoustical and optical properties and X-ray diffraction patterns of a-As2S3 induced by injecting high frequency and high energy CdS acoustic domains. At first the bonding techniques for high frequency acoustic wave transmission are experimentally examined for various bonding agents. Then, high energy acoustic domains are injected into the a-As2S3 and the samples are examined by optical transmission and X-ray diffraction. The acoustic flux injection causes a structural change in the a-As2S3 which is recovered by annealing. It is shown that high energy acoustic injection is equivalent to annealing in a furnace.
Photovoltaic Effect in Ferroelectric Ceramics and Its Applications
Authors: Uchino Kenji , Miyazawa Yuichi , Nomura Shoichiro
Published: March 2014

The bulk photovoltaic effect has been investigated in the ferroelectric PbTiO3-based and PLZT-family ceramics. The highest photovoltaic power (the photoelectric transducer efficiency of about 20 ppm) thus far obtained is in the 0.9PbTiO3-0. 1Pb(Mg1/2W1/2)O3 solid solution. Using this composition, a beam intensity sensor has been fabricated with an interdigital electrode pattern on the surface.
Effect of Cell Thickness on Electrical Property of Ferroelectric Liquid Crystal and High Speed Optical Switching and Memory Element
Authors: Yoshino Katsumi , Urabe Takashi , Inuishi Yoshio
Published: March 2014

Dielectric properties of ferroelectric liquid crystal depend strongly on the cell thickness. The result is discussed in terms of the free energy theory by Pikin et al with taking effects of the thickness on the relaxation time into consideration for the cell thicker than 10 µm. For the thinner cells, the effect of hindered roation due to the influence of wall must be taken into consideration.
Switching time of electro-optical effect with DOBAMBC and HOBACPC in very thin cells is in the range of µsec but the time of HOBACPC is much shorter than that of DOBAMBC.
PLZT Electrooptic Shutter
Authors: Tanaka Katsuhiko , Yamaguchi Masami , Seto Hiroyuki , Murata Michihiro , Wakino Kikuo
Published: March 2014

A PLZT electrooptic shutter composed of several regions each having a different electric field shows some excellent properties such as good transmittance spectra and stable operation against fluctuations in driving voltage and ambient temperature.
Chemical Vapor Deposition of PbTiO3 Thin Film
Authors: Kojima Motohiro , Okuyama Masanori , Nakagawa Taichi , Hamakawa Yoshihiro
Published: March 2014

A PbTiO3 thin film has been grown on Pt or Pt-coated Si wafer by chemical vapor deposition instead of rf sputtering which makes a surface of substrate damaged. As the source material of the deposition, two kinds of combinations of (PbCl2 and TiCl4) and (PbO and Ti(C4H9O)4) have been tried to know the effect of chlorine inclusion in the PbTiO3 network. The surface of the film is much smoother than that of the film prepared by the rf sputtering, and deposition rate is several µm/hr. The deposited film structure is mostly oriented to <100> or <110> direction which depends on the source material and the deposition condition. The maximum dielectric constant of the film is 130, and D-E hysteresis characteristic has been also obtained.
A Method for Measuring the Equivalent Circuit Elements for a Piezo-Resonator
Authors: Terunuma Kazuhiko , Nishigaki Susumu
Published: March 2014

This paper presents a new method for measuring the equivalent circuit elements of a piezo-resonator.
This method is based on the fact that the sum of the squares of the difference between the input free admittance and the calculated admittance can be minimized by the method of the least squares.
This new method is applicable even for resonators with low mechanical Q and small figure of merit M in which the plot of admittance Y

i
against conductance G and susceptance B is distorted.
Sm-Substituted Lead Titanate Ceramics for High Frequency Ultrasonic Probes
Authors: Takeuchi Hiroshi , Jyomura Shigeru , Nakaya Chitose , Ishikawa Yasuo
Published: March 2014

Modified lead titanate ceramics with exceptionally large electromechanical anisotropy (ratio of electromechanical coupling factor for thickness vibration to that for planar vibration is more than 15) are produced. These ceramics have a chemical formula (Pb1-(3x/2)Sm
x
) (Ti1-y
Mn
y
)O3. They are found to be very useful in ultrasonic probe applications due to their extremely small coupling factor of unwanted lateral vibration (k
31, k
p). High frequency (7.5∼15 MHz) ultrasonic probes using these ceramics are developed for medical use.
The Influence of Mn-Doping on Ultrasonic, Elastic, and Dielectric Properties of Ferroelectric (Pb, Ca)TiO3 Ceramic Materials
Authors: Iwasaki Hideo , Yamashita Youhachi , Yoshida Sei-ichi
Published: March 2014

In order to confirm the role of Manganese on properties of PbTiO3-like ferroelectric ceramics, ultrasonic, elastic, dielectric, and DC resistance characteristics have been measured before and after poling as a function of Mn-concentrations in the range from 0 to 4 mol% in ferroelectric (Pb0.75 Ca0.25)((Mg1/3 Nb2/3)0.0625 Ti0.9375)O3 ceramics, in connection with the microstructures such as grain size and lattice constants. Observed results show that energy dissipation factors such as ultrasonic attenuation, dielectric loss, and DC resistance are markedly Mn-concentration sensitive.
Dielectric and Piezoelectric Properties of Hot-pressed Pb1-xBaxNb2O6 Ceramics
Authors: Yokosuka Masaru
Published: March 2014

Investigations have been made on the hot-pressed and ordinary fired ceramics of tungusten bronze type of solid solution Pb1-x
Ba
x
Nb2O6, where x is varied from 0.3 to 0.5. At room temperature, dielectric constants, piezoelectric constants and electromechanical coupling coefficients of hot-pressed ceramics have been found superior to those of ordinary fired ones near the morphotropic phase boundary between the orthorhombic and the tetragonal phase. The maximum values are obtained for Pb0.58Ba0.42Nb2O6.
The effects of a small amount of additives, Co2O3 and Fe2O3, have been also examined and the addition of 0.2 wt% of Co2O3 is found most effective to improve the dielectric and piezoelectric properties.
Electrical Properties of Li-Ti-O Ceramics
Authors: Inukai Takashi , Murakami Toshiaki
Published: March 2014

Li-Ti-O ceramics were prepared by hot-pressing and their electrical properties were examined. It was found that Ti3+ in raw materials played an important role in the formation of the spinel phase with superconductivity. Dense specimens with the spinel phase were prepared at about 900°C, which showed metallic conduction below 40 K. On the Ti-rich side, specimens of which superconducting transition temperature was 13.4 K, were prepared with good reproducibility.
Stress Anisotropy of PLZT Ceramics Induced by Polarization
Authors: Yamamoto Takashi , Sato Hidemori , Igarashi Hideji , Okazaki Kiyoshi
Published: March 2014

The (Pb, La) (Zr, Ti)O3 ceramics were hot-pressed, and a micro-indentation technique was applied to the ceramics before and after poling. Internal stress anisotropies induced by application of dc electric field was found. The fracture toughness increased for the parallel direction to a poling field and decreased for the perpendicular direction due to a compressive and a extensional stress, respectively. The stress anisotropy disappeared by thermal depolarization at above Curie point. The results were explained by a ferroelectric domain rearrangement.
Acoustic Power Generated from ZnO Film Ultrasonic Transducers and its Saturation Properties
Authors: Yamamizu Shuichiro , Natsui Takeo
Published: March 2014

This paper describes the measurements of acoustic power generated from ZnO film ultrasonic transducers. Measurements are carried out for both pulsed and continuous wave (CW) voltages at fundamental resonant frequency of ZnO films and the radiated power into the acoustic medium is estimated using a receiving transducer whose property is known. When CW voltage of 310 MHz is applied to a ZnO film with a film thickness of 9 µm and electrode diameter of 2 mm, the saturation of generated power takes place at a quarter of the breakdown voltage (about 40 V). The saturated acoustic power level is estimated to be 0.64 W/mm2.
A Two Impedance Matching Layer Ultrasonic Transducer Design
Authors: Inoue Takeshi , Takahashi Sadayuki , Ohta Masaya , Konda Shin-ichi
Published: March 2014

A two impedance matching layer ultrasonic transducer for medical diagnostic use was investigated from a new point of view, i.e. “multiple mode filter”. It was found that the transducer showed good performance when the thickness of each matching layer became 1.176λ/4. Obtained fractional bandwidth is 70%, round trip insertion loss is 2.7 dB and passband ripple is less than 1 dB.
Relation of the Insertion Loss and the Triple Transit Echo in SAW Unidirectional Transducers
Authors: Yamada Jun , Hazama Katashi
Published: March 2014

The scattering matrix of SAW unidirectional transducers is calculated on the assumption that it is passive, reversible and lossless. Then the insertion loss and the triple transit echo are obtained as a function of the normalized radiation conductance. The propriety of the theoretical results is verified by experiments.
A 925 MHz SAW Resonator for Capacitive Video Disc Player
Authors: Kanamaru Masaji , Kobayashi Shoei
Published: March 2014

A 925 MHz SAW (surface acoustic wave) resonator has been developed for use in the oscillator of the capacitive pickup in a video disc system. The resonator, which consists of an IDT and a pair of reflectors with absorber on the 128°-rotated Y-cut LiNbO3 substrate, has an insertion loss of 3 dB and an output impedance of 80 ohms. The resonator permits a hybrid IC of the 925 MHz SAW oscillator to be realized without frequency-multiplier circuits and eliminates the need for oscillator adjustment.
New SECAM Composite SAW IF Filter Separating the Sound and Picture Signals
Authors: Wakamori Satoshi , Oda Kohji , Toyama Tatsuro
Published: March 2014

A new Surface Acoustic Wave (SAW) filter for the French L/SECAM system has been developed. It has two input transducers and two output transducers which are constructed on 128°Y-XLiNbO3 and it separates the input signal into sound and picture signals for use in the L/SECAN system which uniquely utilizes an AM sound signal. The size is the same as that of the conventional SAW IF filter, and it is sealed in a TO-8 can package. Compared with previous models, this new SAW filter enables the TV IF circuit to lower the sound-picture crossbeat interference (the beat noise in speakers) by 3.4 dB and reduces the number of electrical parts.
Surface Acoustic Soliton
Authors: Sakuma Tetsuro , Kawanami Yoshimi
Published: March 2014

The theory of surface acoustic soliton is presented based on the coherent-state representation of the equation of motion for anharmonically interacting surface-phonons. It is shown that the two-dimensional wave field satisfies the nonlinear integro-differential equation which can be reduced to the nonlinear Schrödinger equation by means of reductive perturbation method. The possibility of detecting the surface acoustic soliton is also discussed.