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The local structure of boron-doped highly oriented graphite films was determined via soft x-ray emission and absorption spectroscopy using synchrotron radiation. Analysis of the BK and CK x-ray emission spectra using the discrete variational-Xα molecular orbital method clarified that boron atoms are chemisorbed onto graphite by substituting for carbon atoms in the carbon hexagonal rings. Compared to graphite, boron-doped graphite exhibits spectral differences in the higher edge of the CK x-ray emission spectrum and the CK x-ray absorption edge. Such a spectral profile of boron-doped graphite, which reflects the band structure, is well explained by the chemisorbed boron structure. [ABSTRACT FROM AUTHOR]

Highly conducting and transparent aluminum-doped zinc oxide films were prepared on quartz and corning glass 7059 substrate by ablating the sintered ZnO target containing 2 wt % Al[sub 2]O[sub 3] with a XeCl excimer laser (λ=308 nm). To grow the films, a repetition rate of 5 Hz and energy density of 1.5 J/cm2 was kept. The effect of substrate temperature from room temperature to 400 °C and oxygen pressure (0.1–5 mTorr) have been investigated by analyzing the optical and electrical properties of these films. The average transmittance was found to be in the range of 86%–92%, and a variable resistivity (ρ) 3.56×10[sup -3]–7.0×10[sup -3] Ω cm have been obtained. The lowest resistivity was found to be 1.4×10[sup -4] Ω cm at 300 °C in 1 mTorr of oxygen pressure. Structural changes in the films were also investigated by determining the full width at half maximum of (002) x-ray diffraction peak. These results show improvement in the crystallinity of films, which support our conductivity and transmittance data. The sharp decrease in the transmittance or sharp increase in reflectance near the plasma edge in the near-infrared range has been attributed to impurity scattering, which is Al doping in our films. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents information on a study which described a selective plasma oxidation method for use in making superconducting patterns in nonsuperconducting deoxygenated YBa[sub2]Cu[sub3]O[sub7-x] (YBCO) thin films. Electrical properties of the thin films; Description of the selective plasma oxidation of YBCO films using a metal mask; Effects of plasma oxidation on polycrystalline YBCO films; Conclusions.

Presents information on a study which fabricated niobium (Nb)/AlO[subx]Nb Josephson junctions which showed excellent current-voltage characteristics. Deposition of Nb and aluminum layers to get a clear junction interface; Fabrication of 10[sup4] junctions connected in series; Estimation of the yield.

Presents a study which investigated the effect of mechanical strain on the current-voltage characteristics of hydrogenated amorphous silicon p-i-n junctions. Relation between the strain effect and the voltage dependence of the sensitivity; Effect of strain on the distribution of localized states and on the recombination processes.

Defect chalcopyrite thin films of Cu(In,Ga)[sub 2]Se[sub 3.5] were prepared by rf sputtering from stoichiometric CuIn[sub x]Ga[sub 1-x]Se[sub 2] (x = 0.6) and Na mixture target. The composition of the thin films fabricated in the ratio of [Na]/[Cu(In,Ga)Se[sub 2]] above 5% was changed from the stoichiometric composition of Cu(In, Ga)Se[sub 2] to Cu-poor one, and identified as Cu:(In+Ga):Se=1:2:3.5. From the results of x-ray diffraction, the lattice parameters of these thin films were slightly smaller than that of Cu(In,Ga)Se[sub 2] and, besides the peaks appearing for chalcopyrite structure Cu(In,Ga)Se[sub 2], the additional peak was observed. The optical band gap is increased from 1.24 to 1.36 eV with increasing the [Na]/[Cu(In,Ga)Se[sub 2]] ratio from 0% to 10% in the target. These films showed n- or p-type conduction. [ABSTRACT FROM AUTHOR]

Presents a study on the structural properties of indium nitride films grown on (0001) sapphire (α-dialuminum trioxide) substrates, using reflection high-energy electron-diffraction and x-ray-diffraction methods. Epitaxial relationship between InN layer and the α-dialuminum trioxide substrate; Experimental procedure; Results and discussion.

Reports on the structural properties of CuIn[subx]Ga[sub1-x]Se[sub2] thin films prepared by radio frequency sputtering. X-ray diffraction analyses of the thin films; Surface morphology of the thin films; Composition of CuIn[subx]Ga[sub1-x]Se[sub2] thin films.

Presents a study which investigated the structural, electrical and optical properties of copper indium selenide thin films produced by rf sputtering with intentional oxygen doping. Characteristics of the thin films; Dependence of growth rate and surface morphology on the constituent gas ratio for the thin films; Result of the transmittance measurements.

Presents a study that prepared tin oxide thin films with low resistivity by chemical vapor deposition. Details of the experiment; Experimental results; Discussion.

Studies the piezoresistance in n-channel inversion layers of silicon films on sapphire. Applications of piezoresistance of silicon; Calculations of piezoresistance coefficients of n-channel sapphire substrates inversion layers; Details on the experimental methods.

Photoelectromagnetic effects in CulnSe[sub 2] (CIS) thin films irradiated with 3 MeV electrons or 380 kev protons have been investigated to evaluate the diffusion length. CIS thin films were deposited by radio frequency sputtering. The diffusion length was decreased due to irradiation-induced defects, as the electron fluence exceeded 1 × 10[sup 16] cm[sup -2]. The damage constant was estimated from the change in diffusion length before and after irradiation, and was about 4 × 10[sup -9]. After proton irradiation, the diffusion length decreased significantly as the proton fluence exceeded 1 × 10[sup 13] cm[sup -2]. The damage constant in this case was estimated to be about 1 × 10[sup -4]-4 × 10[sup -5]. [ABSTRACT FROM AUTHOR]

Reports on the transistor characteristics of a three-terminal structure having YBa[sub2]Cu[sub3]O[sub7-x] electrodes on an insulating SrTiO[sub3] substrate with an intervening NdGaO[sub3] barrier. Illustration of the device structure; Schematic band diagrams of emitter-grounded dielectric-base transistor.

Presents information on a study which examined the thermal stability of indium nitride single crystal films. Surface morphology of the samples; Results and discussion; Conclusions.

Develops a novel method of the selective epitaxy of indium phosphide by employing a two-step growth in atmospheric pressure metalorganic chemical vapor deposition. Kinds of growth procedures of the selective epitaxy; Predeposition and epitaxial growth conditions for selective epitaxy of indium phosphide; Surface morphologies of the selective epitaxial layer for each process and its Talystep profile perpendicular to the silicon dioxide stripe.

A new concept of double-decker electron beam accelerator based on a photocathode radio-frequency (rf) gun was proposed for studying chemical kinetics and primary processes or reactions of radiation chemistry. The synchronized double-decker electron beams with time interval of 1.4 ns were generated in the rf gun by injecting two laser beams on the photocathode. The double-decker electron beams were accelerated by a booster linear accelerator (linac) up to 31.8 MeV with energy-phase correlation and compressed into femtosecond by rotating the bunch in the energy-phase distribution in magnetic fields. The normalized transverse emittance of both beams downstream of the linac was obtained to be 2.5±0.6 mm mrad for the up beam with bunch charge of 0.47 nC and 3.6±0.7 mm mrad for the down beam with bunch charge of 0.65 nC. The minimum relative energy spread was (0.14±0.03)% for the two beams. The compressed bunch length was obtained to be 430±25 fs for the up bunch and 510±20 fs for the down bunch. [ABSTRACT FROM AUTHOR]

Reports the degradation of hydrogenated amorphous silicon films induced by irradiation of synchrotron radiation light. Preparation of samples by radio-frequency glow-discharge decomposition; Dependence of photoconductivity on the power of visible light illumination as a function of irradiation time; Description of the proposed direct bond-breaking model for the degradation mechanism.

Studies nanoscale conduction modulation in an Au-tip/Pb(Zr,Ti)O[sub 3]/SrRuO[sub 3] heterostructure using the Au-coated cantilever of scanning probe microscopy as a mobile top electrode. Polarization-induced pattern written in the ferroelectric layer of the heterostructure.

Examines the reduction of the operating voltage in dielectric-base transistor with doped channel. Impact of conduction band lowering on operating voltage; Relationship between voltage amplification factor and threshold voltage; Distance of the base electrode from the emitter electrode.

Focuses on the transistor characteristics of a three-terminal structure on an insulating strontium titanium oxide substrate. Fabrication of a superconducting YBa[sub 2]Cu[sub 3]O[sub 7-x] emitter; Construction of the three-terminal structures on crystals; Formation of base leads by silver paste.

Examines a transistor based on electrical potential control through high-dielectric-constant insulators. Fabrication of ultrafast superconducting transistors; Production of base leads with silver paste; Control of the collector current.

Hydrogenated amorphous silicon films were deposited by the direct photolysis of disilane using windowless hydrogen discharge. Electrical and optical properties of the films have been investigated. The photosensitivity (σph/σd) is about 107 in the films prepared at 250 °C, better than that of films obtained by conventional rf plasma chemical vapor deposition. [ABSTRACT FROM AUTHOR]

Epitaxial layers of InN films were grown onto (0001) α-Al2O3 substrates in the temperature range of 400–600 °C by microwave-excited metalorganic vapor phase epitaxy using (CH3)3In and N2. Specular surface was obtained at a low substrate temperature (<500 °C) with a relatively high microwave power (>100 W). From reflection high-energy electron diffraction analysis, the deposited films were found to be crystalline InN with an orientation relation of (0001) InN//(0001) α-Al2O3. The stoichiometry of the grown films was found to be similar to that reported for bulk InN from electron spectroscopy for chemical analysis. [ABSTRACT FROM AUTHOR]

The effects of mechanical strain on the electrical properties of p-i-n hydrogenated amorphous silicon junction devices were investigated. When strain was applied parallel to the junction plane, both the forward and reverse currents increased with increasing compressive strain and decreased with increasing tensile strain. The ratio for change in current was 8% under the strain of 7.5×10-4, and the strain sensitivity was as large as that in the piezoresistance effect of crystalline silicon. The strain dependence is due to a change in carrier concentration induced by a displacement of energy band and a change in carrier lifetime. [ABSTRACT FROM AUTHOR]

Plasmaless etching using ClF3 gas around room temperature has been investigated for the silicon substrates with the various thicknesses of native oxide. The native oxide can be removed with ClF3 gas. A specular surface is obtained by ultraviolet light irradiation which remarkably accelerates the removal of the native oxide without changing the etch rate of silicon. The etched surface is analyzed with Auger electron measurement, indicating the existence of Cl atoms on it. [ABSTRACT FROM AUTHOR]

Photochemical vapor deposition of carbon films from n-butane gas has been successfully done, for the first time, at room temperature using synchrotron radiation as a light source. The deposited films are hydrogenated amorphous carbon films with sp3 bonds. The deposition rate increases with negative bias. [ABSTRACT FROM AUTHOR]

We report Raman scattering study on InN single crystalline films with wurtzite form. The films were grown on sapphire substrates by microwave-excited metalorganic vapor phase epitaxy and optical phonon properties of the films were investigated. Both A1(LO) and E2(2) peaks, which are related to a longitudinal optical phonon mode and a doubly degenerated mode, respectively, were observed at 596 cm-1 with the full width of 36 cm-1 at half maximum intensity and at 495 cm-1 with the full width of 20 cm-1 at half maximum intensity. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents a response to a comment on the structural properties of CuIn[subx]Ga[sub1-x]Se[sub2] thin films prepared by rf sputtering. Determination of the structure of the CuIn[subx]Ga[sub1-x]Se[sub2] system; Composition of CuInSe[sub2].

Plasma polymerization using CHF3 gas, which prevents the degradation of high Tc oxide superconductors due to moisture and annealing, was developed. The resistive transitions of Y1Ba2Cu3Ox thin films, coated by plasma polymerization, did not change before and after soaking in 20 °C water for 60 min. In addition, the critical temperature of those films was unchanged after annealing at 200 °C for 30 min in air, and then soaking in 90 °C water for 10 min. We confirmed that the polymer film grown by this method was dense, and the Y1Ba2Cu3Ox film reacted with the fluorine at the interface using x-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]