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Showing papers in "Japanese Journal of Applied Physics in 1983"


Journal ArticleDOI
TL;DR: In this article, the authors applied the direct measurement of spontaneous polarization using triangular waves to ferroelectric liquid crystals and found no existence of the threshold voltage for deforming the helix.
Abstract: It is proposed to apply the direct measurement of spontaneous polarization using triangular waves to ferroelectric liquid crystals. The use of the triangular waves allows us to easily subtract the background contribution due to the conductive and the capacitive current and to accurately determine the spontaneous polarization, since a bump due to the polarization realignment appears on a straight base line. Moreover, the experiment with pulsed triangular waves clearly reveals no existence of the threshold voltage for deforming the helix and some characteristic properties of the dynamic reaction of the helix to the field applied.

516 citations


Journal ArticleDOI
TL;DR: In this paper, the acceleration effect of ions with moderate energies (10 to 20 eV), using a microwave ECR (Electron Cyclotron Resonance) excited plasma, and a plasma stream extraction onto the specimen table by a divergent magnetic field method.
Abstract: The plasma deposition apparatus developed in this study can realize a deposition of dense and high quality thin films, such as Si3N4 and SiO2, without the need for substrate heating. It does this by enhancing the plasma excitation efficiency at low gas pressures (10-4 Torr) and by the acceleration effect of ions with moderate energies (10 to 20 eV), using a microwave ECR (Electron Cyclotron Resonance) excited plasma, and a plasma stream extraction onto the specimen table by a divergent magnetic field method. The Si3N4 and SiO2 films deposited are comparable to those prepared by high temperature CVD and thermal oxidation, respectively, in evaluations such as by buffered HF solution etch rate measurement.

294 citations


Journal ArticleDOI
Ryuichi Shimizu1
TL;DR: In this article, a short review of the theoretical background of a physical model for the quantification of Auger electron spectroscopy (AES) for surface analysis is presented, and functional representations of the backscattering factors for different angles of incidence (ψ) for primary energies ranging from 3 to 10 keV are proposed.
Abstract: A short review is presented of the theoretical background of a physical model for the quantification of Auger electron spectroscopy (AES) for surface analysis. The recent studies on the data-base for the inelastic mean free paths (IMFP) by Seah and Dench and systematic calculations of the backscattering factors (R) by Shimizu and Ichimura have now enabled standard quantitative corrections comparable to those widely used in electron probe microanalysis, to be accomplished. For quantitative corrections of wider practical use, the present paper proposes the use of functional representations of the backscattering factors for different angles of incidence (ψ) for primary energies ranging from 3 to 10 keV as follows: R=1+(2.34-2.10Z0.14)×U-0.35+(2.58Z0.14-2.98) for ψ=0°, R=1+(0.462-0.777Z0.20)×U-0.32+(1.15Z0.20-1.05) for ψ=30°, R=1+(1.21-1.39Z0.13)U-0.33+(1.94Z0.131.88) for ψ=45°, where U is the ratio of the primary energy to the binding energy, and Z is the atomic number of a sample.

239 citations


Journal ArticleDOI
TL;DR: In this paper, the RHEED intensities were calculated from the products of matrices obtained from Bethe's dynamic diffraction theory for each slab, and the crystal potential in each stab was taken as constant the normal to the surface.
Abstract: In order to calculate RHEED intensities by using the dynamic electron diffraction theory, crystals are sliced in thin stabs parallel to the surface. The crystal potential in each stab is taken as constant the normal to the surface. The RHEED intensities are calculated from the products of matrices obtained from Bethe's dynamic diffraction theory for each slab.

200 citations


Journal ArticleDOI
TL;DR: In this paper, a secondary battery utilizing polythiophene films as cathode and anode active materials in an electrolyte of TBABF4/MeCN was studied, and the cell potential, energy density and maximum power density were observed to be 3.1 V, 93 Wh/kg and 89 kW/kg, respectively.
Abstract: A secondary battery utilizing polythiophene films as cathode and anode active materials in an electrolyte of TBABF4/MeCN is studied. The cell potential, energy density and maximum power density (based on the weight of cathode and anode films) are observed to be 3.1 V, 93 Wh/kg and 89 kW/kg, respectively, for the dopant concentration of 24 mol%.

151 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the electron mobility in selectively doped GaAs/N-AlxGa1-xAs (x=0.3) heterostructures grown by MBE.
Abstract: Electron mobility of quasi-two dimensional electron gas (2DEG) in selectively doped GaAs/N-AlxGa1-xAs (x=0.3) heterostructures grown by MBE was investigated as a function of thickness of an undoped AlxGa1-xAs spacer-layer (0–200 A) introduced between a Si-doped AlGaAs layer and an undoped GaAs layer, at 77 K and 5 K. Mobility of 2DEG as high as 2,120,000 cm2/Vs at 5 K was achieved with a spacer-layer thickness of 200 A. This electron mobility is higher than any observed so far in semiconductor materials.

140 citations


Journal ArticleDOI
TL;DR: In this paper, the spectral width and shape of photoluminescence spectra for undoped superlattices were found to be sensitive to the well size of the well.
Abstract: Photoluminescence spectra for undoped superlattices exhibited smaller half widths compared with those obtained in GaAs bulk crystals. However, both the spectral width and shape were found to be very sensitive to the well size. When the well size is greater than about 80 A, the spectrum at 77 K showed smaller linewidth, which agrees with theoretical results, whereas when the well size is smaller than this, the spectral width increased with decreasing well size. In some cases, additional emission bands appeared in the lower energy side of the main emission peak. These phenomena were interpreted in terms of well size fluctuations.

127 citations


Journal ArticleDOI
TL;DR: In this article, the resistivity and structure of films deposited on tantalum and rocksalt substrates by the electron beam evaporation of boron and the simultaneous bombardment of 30 keV N2+ ion beam were studied.
Abstract: The resistivity and structure of films deposited on tantalum and rocksalt substrates by the electron beam evaporation of boron and the simultaneous bombardment of 30 keV N2+ ion beam were studied. From observation by transmission electron microscope, it was found that cubic boron nitride was produced in the case where the prepared composition rate of boron to nitrogen was 2.5.

122 citations


Journal ArticleDOI
TL;DR: In this paper, the magneto-birefringence of magnetic fluid thin films of 12 µm and 25 µm was studied and anomalous phase differences were found when an external magnetic field was applied normal to the direction of light propagation.
Abstract: The magneto-birefringence of magnetic fluid thin films of 12 µm and 25 µm were studied and anomalous phase differences were found when an external magnetic field was applied normal to the direction of light propagation. The order of the phase differences of the films was about 107 times larger than that of nitrobenzene, which is known to show a large Cotton-Mouton effect. We attribute these phenomena theoretically to a rod-like chain formation of the ferrite particles in the magnetic fluid thin films and derive expressions for the phase difference and absorption. There is a definite difference in the H-\vartheta curves between theory and experiment in the rising gradient near H=0.

116 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of grain angle in the longitudinal-radial plane on Young's modulus and internal friction of wood was investigated and it was concluded that the value of internal friction as well as Young's motes of wood is determined in large part by microfibril angles in the S2 layer of tracheid against the L direction.
Abstract: Young's modulus E and internal friction Q-1 in longitudinal (L) direction and specific gravity γ were measured for numerous specimens of 25 softwood species. There was a high correlation between Q-1/(E/γ) and E/γ, and the suitability of wood for musical instruments can be evaluated by using the value of E/γ. Furthermore, effects of grain angle in the longitudinal-radial plane on Young's modulus and internal friction of wood were investigated. From these results, it is concluded that the value of internal friction as well as Young's modulus of wood is determined in large part by microfibril angle in the S2 layer of tracheid against the L direction.

103 citations


Journal ArticleDOI
TL;DR: In this article, a new type of amorphous silicon (a-Si) solar cell stacked with polycrystalline silicon (poly-c-Si), has been developed, and the conversion efficiency more than 12% has been obtained with a cell structure of ITO/n-i-p a-Si/p poly c-Si//Al.
Abstract: A new type of amorphous silicon (a-Si) solar cell stacked with polycrystalline silicon (poly-c-Si) has been developed. The conversion efficiency more than 12% has been obtained with a cell structure of ITO//n-i-p a-Si//n a-Si/p poly c-Si//Al. A series of technical data on the cell fabrication and resulting photovoltaic characteristics are presented.

Journal ArticleDOI
TL;DR: In this paper, new optical switching and memory elements utilizing the spectral change of conducting polymers by electro-chemical doping and undoping are proposed, which can be used for memory elements.
Abstract: New optical switching and memory elements utilizing the spectral change of conducting polymers by electro-chemical doping and undoping are proposed.

Journal ArticleDOI
TL;DR: Growth conditions and structures of vacuum-evaporated heteroepitaxial CaF2, SrF2 and BaF2 films on (111) and (100) oriented Si substrates have been investigated as discussed by the authors.
Abstract: Growth conditions and structures of vacuum-evaporated heteroepitaxial CaF2, SrF2 and BaF2 films on (111) and (100) oriented Si substrates have been investigated. Single crystal CaF2 films are grown on both Si(111) and (100) substrates at temperatures of 600–800°C and 500–600°C, respectively. CaF2 films on Si(111) have crystal orientations rotated 180° about the normal to the substrate surface. SrF2 and BaF2 films of good crystalline quality are grown on Si(111) at temperatures around 600°C, but are composed of two types of crystallites which have orientations either idential to those of the substrate or rotated 180° on the substrate surface about the surface normal. SrF2 and BaF2 films grown on Si(100) contain (111) oriented crystallites, and, in an extreme case, completely (111) oriented BaF2 films were grown on Si(100).

Journal ArticleDOI
TL;DR: In this paper, the spectral change of conducting polymers by electrochemical doping and undoping is studied and three color states of yellow green, dark brown, and blue are demonstrated for polypyrrole film in the electrolyte of LiBF4/acetonitrile.
Abstract: Detailed characteristics of electro-optic elements (color switching and memory) utilizing the spectral change of conducting polymers by electrochemical doping and undoping are studied. The response time of color switching, for example, red↔blue in polythiophene film in the electrolyte of LiBF4/acetonitrile is 30~100 msec under the applied voltages of -2.0↔+4.0 V vs. Li plate. More than 103 cycles of color switch are observed quite reproducibly. Three color states of yellow green, dark brown and blue are demonstrated for polypyrrole film.

Journal ArticleDOI
TL;DR: In this paper, the authors describe the principle and performance of the new method, which facilitates formattion of crystalline spinel films at low temperature (<80°C) for various compositions, and on substrates of not only metal but also oxide and organic compounds.
Abstract: We describe the principle and performance of the new method. It facilitates formattion of crystalline-spinel films at low temperature (<80°C) for various compositions, and on substrates of not only metal but also oxide and organic compounds. Hydrolyzed metal ions in an aqueous solution (pH=6~11, T=40~80°C) are incorporated into the spinel film on the substrate associated with air oxidation or anodic oxidation of ferrous ion. We have plated Fe3O4 and CoFe2O4 films on substrate of Cu, PET and stainless steel. They are polycrystalline with no preferred orientation, exhibiting no magnetic anisotropy. Polar Kerr rotation of these films has been measured.

Journal ArticleDOI
TL;DR: A superlattice with an exceptionally short period composed of 15 A AlAs and 25 A selectively Si doped GaAs is grown by molecular beam epitaxy (MBE) as discussed by the authors.
Abstract: A superlattice with an exceptionally short period composed of 15 A AlAs and 25 A selectively Si doped GaAs is grown by molecular beam epitaxy (MBE). The persistent photoconductivity (PPC) is drastically decreased by the Al and Ga separation, and deep level formation is effectively suppressed by the Al and Si separation compared with n-AlxGa1-xAs (x>0.25), which has the same bandgap as the superlattice. Consequently, an extremely high quality Al–Ga–As:Si solid system is realized for the first time with high donor activation coefficient and low activation energy (<10 meV) for thermal carrier generation.

Journal ArticleDOI
TL;DR: In this article, the static characteristics of amorphous-silicon field effect transistors have been analyzed under the assumption that the localized state density distribution (LSDD) takes on an exponential or uniform form, and the experimental data is qualitatively in good agreement with the theoretical results of the exponential LSDD.
Abstract: Static characteristics of amorphous-silicon field-effect transistors have been analyzed under the assumption that the localized state density distribution (LSDD) in amorphous-silicon with respect to energy takes on an exponential or uniform form. In the case of an exponential LSDD, logarithmic drain current ID vs logarithmic gate voltage VG characteristics of the FET for large VG is found to be linear, the slope of which yields the characteristic temperature of the exponential LSDD. While, in the case of a uniform LSDD, log (IDVG)–VG curves for large VG are found to be linear. The experimental data is qualitatively in good agreement with the theoretical results of the exponential LSDD.

Journal ArticleDOI
TL;DR: In this paper, an infrared light scattering tomography was developed to characterize semiconductor crystals, which successfully gave clear images of micro-defects in a heat-treated Si crystal and dislocation networks in a GaAs crystal grown by a horizontal Bridgman method.
Abstract: Most semiconductor crystals are transparent for infrared rays but some of them are difficult to study by X-ray methods if they are composed of heavy elements. An infrared light scattering tomography, which is developed in this paper to characterize semiconductor crystals, successfully gives clear images of micro-defects in a heat-treated Si crystal and dislocation networks in a GaAs crystal grown by a horizontal Bridgman method.

Journal ArticleDOI
TL;DR: Optical bistability has been observed in a semiconductor laser operating as an amplifier as mentioned in this paper, which arises from the refractive index change due to a decrease in the active region carrier density accompanied by optical amplification.
Abstract: Optical bistability has been observed in a semiconductor laser operating as an amplifier. The bistability arises from the refractive index change due to a decrease in the active-region carrier density accompanied by optical amplification. Output pulsations due to the competition between the free-carrier and thermal effects have also been observed.

Journal ArticleDOI
TL;DR: In this article, a computer controlled multi-channel PICTS system which allows one to detect many deep trapping levels in high resistivity bulk material by only a single thermal scanning process, has been developed.
Abstract: A computer controlled multi-channel PICTS system which allows one to detect many deep trapping levels in high-resistivity bulk material by only a single thermal scanning process, has been developed. In order to obtain the normalized PICTS signal, an automatic gain controlled pre-amplifier has been used. An expanded-scale technique which allows one to distinguish fine PICTS peaks has been proposed. This expanded-scale technique is very useful especially for the case when many PICTS peaks are closely superposed. In high-resistivity bulk CdS single crystal, it has been found that PICTS spectrum-shape and number of detected peaks depend strongly upon the wavelength of exciting laser light, and that the trap-parameters obtained are not strongly influenced by light intensity. The PICTS method may be superior on many points, especially in peak-separation, to the thermally stimulated current method.

Journal ArticleDOI
TL;DR: In this paper, it was shown that left-circularly polarized light incident on a left-handed helix gives rise to a beat structure in the subsidiary oscillation, while right-Circularly polarised light causes a swell to be superimposed on the subsidiary waveform.
Abstract: Many optical properties are presented here in the reflection spectra for monodomain cholesterics of various cell thicknesses at various angles of incidence. It is reported for the first time that left-circularly polarized light incident on a left-handed helix gives rise to a beat structure in the subsidiary oscillation, while right-circularly polarized light causes a swell to be superimposed on the subsidiary oscillation. The beat structure is ascribed to the excitation of two sets of optical eigen modes, each set consisting of two optical eigen modes of slightly different wavelength. The polarization characteristics of the total reflection band as well as the selective reflection band are also discussed.

Journal ArticleDOI
TL;DR: In this article, a new high electron mobility monolayer superlattice (MSL) which consists of alternating InAs and GaAs monolayers is proposed, and the electron mobility of the MSL will be as high as 6×105 cm2/V.
Abstract: A new high electron mobility monolayer superlattice (MSL) which consists of alternating InAs and GaAs monolayers is proposed. Since the disorder scattering inherent in mixed crystals is absent in the MSL's, extremely high electron mobility can be expected. Critical periodicity (well width+barrier width) of the MSL is estimated to be 16 monolayers, below which electronic structure of the MSL becomes three dimensional. A calculation shows that the electron mobility of the MSL will be as high as 6×105 cm2/V.sec at around 50 K for ND-NA=1×1014 cm-3 and NA/ND=0.5, which is more than one order of magnitude higher than In0.5Ga0.5As alloy with the same impurity concentration.

Journal ArticleDOI
TL;DR: In this paper, the photoluminescence peak at 1.4 eV was observed for a specimen grown at 200°C and the bonding configurations varied from silicon dihydride to monohydride with increasing substrate temperature, and correspondingly the dark conductivity decreased from 10-7 to 10-11 Ω-1cm-1.
Abstract: Silicon thin-films have been deposited by the direct photolysis of disilane at a substrate temperature below 300°C. The growth rate depends on irradiation intensity of a low pressure mercury-lamp, and a typical rate of 15 A/min has been obtained under ~0.08 watts/cm2 illumination, regardless of substrate temperature. The deposited films are composed of an amorphous network containing bonded-hydrogen in the range 6–9 at.%. The bonding configurations of SiH groups varied from silicon dihydride to monohydride with increasing substrate temperature, and correspondingly the dark conductivity decreased from 10-7 to 10-11 Ω-1cm-1. A broad photoluminescence peak at 1.4 eV was observed for a specimen grown at 200°C.

Journal ArticleDOI
TL;DR: In this article, the effect of Mn doping on the dielectric properties of Ba2Ti9O20 ceramics has been investigated at microwave frequency, and a high value of more than 5200 was obtained at 9 GHz with the addition of 0.5~1.0 mol% Mn.
Abstract: The effect of Mn doping on the dielectric properties of Ba2Ti9O20 ceramics has been investigated at microwave frequency. The dielectric constant and the temperature coefficient are not sensitive to the addition of Mn, while the unloaded Q depends strongly upon it as well as on heat treatment at high temperature. A minute addition of Mn leads to an increase in the Q value. A high value of Q of more than 5200 was obtained at 9 GHz with the addition of 0.5~1.0 mol% Mn.

Journal ArticleDOI
TL;DR: In this article, it has been suggested that a large amount of hydrogen which is not bonded with Si is incorporated in a-Si: H films prepared from Si2H6 and this might be reflected in the dark and photoconductivity of the films.
Abstract: Optical emission spectroscopy and mass spectrometry have been employed as diagnostic tools for studying the glow discharge plasma of pure SiH4 and pure Si2H6. It has been suggested that the dimeric species play an important role in the deposition of a-Si: H from Si2H6 glow discharge in contrast to the monomeric species of SiH dominant in the deposition from pure SiH4. A large amount of hydrogen which is not bonded with Si is incorporated in a-Si: H films prepared from Si2H6 and this might be reflected in the dark and photoconductivity of the films.

Journal ArticleDOI
TL;DR: In this article, the effect of impurities in the carbon paste on the characteristics of solar cells is investigated, and the series resistance and the conversion efficiency are shown to exhibit a strong dependence on O2 concentration in the heating atmosphere.
Abstract: Heating conditions of carbon electrodes for CdTe and the effect of impurities in the carbon paste on the characteristics of solar cells are investigated. The series resistance (Rs) and the conversion efficiency (ηi) of solar cells exhibit strong dependence on O2 concentration in the heating atmosphere. Addition of Cu to the carbon paste causes Rs and diode factor (n) to decrease, resulting in a remarkable improvement in ηi. As a result of preparation of low resistance contact electrode for CdTe, a cell with 0.78 cm2 active area which was made from 50 ppm Cu-added carbon paste showed Voc=0.754 V, Isc=0.022 A, FF=0.606 and ηi=12.8%.

Journal ArticleDOI
TL;DR: In this paper, the absorption spectral lines of the combination tones of the vibration-rotation transitions in NH3 and H2O were measured with 1.5 µm InGaAsP/InP lasers for the purpose of pollutant gas monitoring.
Abstract: The absorption spectral lines of the combination tones of the vibration-rotation transitions in NH3 and H2O were measured with 1.5 µm InGaAsP/InP lasers for the purpose of pollutant gas monitoring. The numbers of observed NH3 and H2O lines were 21 and 1, respectively. The wavelengths of these lines were measured within the inaccuracy of 1.6 pm by a precise wavemeter. For these measurements, the laser wavelength was stabilized to NH3 and H2O lines. The resultant stabilities were 3.0×10-10τ-1/2 and 1.1×10-9, respectively, where τ represents the integration time. The sensitivity of NH3 gas monitoring was measured as being 2.3×10-3 Torr m. Furthermore, spectral measurements obtained by using an optical fiber are also presented.

Journal ArticleDOI
TL;DR: In this paper, a new field effect semiconductor laser or light emitting device is proposed and analyzed, in which the photon emission rate is modulated by the gate voltage mainly through changes in spatial distributions of the carriers.
Abstract: A new field effect semiconductor laser or light emitting device is proposed and analysed, in which the photon emission rate is modulated by the gate voltage mainly through changes in spatial distributions of the carriers. The switching speed in the device is expected to be free from recombination lifetime limitation in specific operation modes.

Journal ArticleDOI
TL;DR: In this article, the piezoelectric and dielectric properties of flexible composites of synthetic rubber and ceramic particles are reported and a theoretically derived "modified" cubes model is presented.
Abstract: The piezoelectric and dielectric properties, particularly those important for hydrophone application, of flexible composites of synthetic rubber and piezoelectric ceramic particles are reported in this paper. Also a theoretically derived "modified" cubes model is presented, which generalizes the parallel, series and cubes models.

Journal ArticleDOI
TL;DR: In this paper, the process of the crystalline-amorphous transition in NiTi induced by electron irradiation has been investigated by a combination of high voltage and conventional electron microscopy, with emphasis on the study of the initiation sites of the transition.
Abstract: Process of the crystalline-amorphous transition in NiTi induced by electron irradiation has been investigated by a combination of high voltage and conventional electron microscopy, with emphasis on the study of the initiation sites of the transition. At the beginning stage of irradiation, a localized amorphization takes place at dislocations so that a cylindrical amorphous region is formed along individual dislocation lines. Continued irradiation brings about the lateral growth of the cylindrical amorphous regions. This is the first time such a preferential transition at dislocations has been observed in metal crystals.