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B-site atomic column regularity was directly observed in (La0.3Sr0.7)(Al0.65Ta0.35)O3 single crystals by Z-contrast imaging during high-angle annular dark-field scanning transmission electron microscopy. Two types of areas with different B-site regularity were found. One of the ordered structures, which was similar to a previously reported structure, was several tens of nanometers in size and had a rock salt-like regularity owing to variation in the B-site Al/Ta ratio. The other structure existed as disordered-like domains in the (La0.3Sr0.7)(Al0.65Ta0.35)O3 crystal. Fourier transform processing revealed that the disordered-like domains consisted of very fine ordered domains of several nanometers in size. These very fine ordered structures had a different B-site Al/Ta ratio variation with a rock salt-like regularity. [ABSTRACT FROM AUTHOR]

Temperature-dependent exciton resonance energies Eexciton in β-Ga2O3 single crystals are studied by using polarized reflectance measurement. The Eexciton values exhibit large energy changes in the range of 179-268 meV from 5 to 300 K. The IR-active Au and Bu optical phonon modes are selectively observed in the IR spectroscopic ellipsometry spectra by reflecting the polarization selection rules. The longitudinal optical (LO) phonon energies can be divided into three ranges: ħωLO = 35-48, 70-73, and 88-99 meV. The broadening parameters, which are obtained from the reflectance measurements, correspond to the lower two ranges of ħωLO at low temperature and 75 meV above 150 K. The large Eexciton changes with temperature in β-Ga2O3 are found to be originated from the exciton-LO-phonon interaction. [ABSTRACT FROM AUTHOR]

Laser-induced fluorescence-dip (LIF-dip) spectroscopy of Ar was used for measuring the distributions of sheath electric fields in low-pressure, inductively-coupled Ar plasmas. A sensitive detection limit of 3 V/cm obtained by LIF-dip allowed the measurement in the presheath region. The distributions of electric fields observed experimentally were compared with those of theoretical calculations based on a simple fluid model. As a result, reasonable agreement between the experiment and the theory was obtained in the electric fields in the sheath region, while the electric fields in the presheath region observed experimentally were higher than the theoretical results. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We measured the distribution of absolute H atom density in high-density, low-pressure CF[sub 4] plasmas with the addition of H[sub 2] by (2+1)-photon laser-induced fluorescence spectroscopy. The H atom density had hollow-shaped distributions, i.e., the H atom density adjacent to the chamber wall was higher than that in the plasma column. In addition, when the chamber wall was covered with hydrogenated fluorocarbon film, we detected H atoms without the addition of feedstock H[sub 2]. These experimental results indicate surface production of H atoms from hydrogenated fluorocarbon film. The surface production rate was sensitive to the property of fluorocarbon film. When the property of fluorocarbon film was unified, the surface production rate increased linearly with the pressure of feedstock H[sub 2], suggesting a recycling process of H atoms between gas phase and fluorocarbon film as a mechanism of plasma–surface interaction in CF[sub 4]/H[sub 2] plasmas. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The effects of adding electronegative SF6 to discharge pumped HgBr and HgCl lasers were compared with those without SF6. A 50% and 40% improvement of the output energies for HgBr and HgCl lasers was realized by adding SF6 to the optimized gas mixture. [ABSTRACT FROM AUTHOR]

Phase-matched second harmonic generation by a surface-plasmon polariton was observed along a silver layer on a slab-type optical waveguide with a Q-switched neodymium:yttrium aluminum garnet laser (1.064 μm). A numerical analysis previous to the experiment was carried out by a perturbation method employing the conception of coupled modes between surface polariton waves and guided waves. In this case the slab-type optical waveguide played the role of an energy storage layer to realize a longer macroscopic propagation length. [ABSTRACT FROM AUTHOR]

Schottky barrier contacts have been made on n-type 3C-SiC epitaxially grown by chemical vapor deposition, and their characteristics were studied by the capacitance and photoresponse measurements. By evaporating Au onto chemically etched surfaces of 3C-SiC, good quality Schottky barrier junctions have been obtained. The barrier height determined by the capacitance measurements is 1.15 (±0.15) eV, while the height by the photoresponse measurements is 1.11 (±0.03) eV. These values are about a half of the energy band gap Eg at room temperature. [ABSTRACT FROM AUTHOR]

In situ analysis of the terminating atomic plane of c-axis oriented La[sub 0.7]Sr[sub 0.3]MnO[sub 3] thin films grown epitaxially on SrTiO[sub 3](100) substrate by laser molecular beam epitaxy has been carried out employing coaxial impact-collision ion scattering spectroscopy (CAICISS). The CAICISS time-of-flight spectroscopic studies reveal that the (001) surface of c-axis oriented La[sub 0.7]Sr[sub 0.3]MnO[sub 3] thin films is predominantly terminated with MnO[sub 2] plane. The azimuth rotational CAICISS measurements show a fourfold symmetry in the surface atom alignments establishing the square lattice structure of the terminating plane. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]