MgO buffer layers were deposited on GaAs by pulsed laser deposition for epitaxial growth of BaTiO3. MgO was grown epitaxially on GaAs for the first time; the orientation is (001) on GaAs(001). The best crystallographic quality was obtained at 350 °C in 5×10−6 Torr O2. BaTiO3 films with (001) orientation grew epitaxially on MgO/GaAs. The in-plane epitaxial relationship was BaTiO3[100]∥ MgO[100]∥ GaAs[100] in spite of a large lattice mismatch (25.5%) between MgO and GaAs.

Pb,La)(Zr,Ti)O 3 (PLZT) is one of the best candidates in terms of high-speed, low-voltage, and low-power consumption optical switching due to its efficient voltage-induced index change. We have established a solid-phase epitaxy to grow low-loss PLZT thin film waveguides. PLZT waveguides with PLZT buffer layers are grown on Nb-doped semiconductive SrTiO 3 substrates for the effective overlap integral of the optical field and the electric field. Efficient switching of light coupled in the waveguides is achieved by applying voltage between the top electrodes and the substrates to induce the excellent electro-optic properties of PLZT waveguides including low-voltage and polarization independent index change. 1xN optical switching devices and subsystems are demonstrated using the PLZT waveguide switch elements showing low-voltage drive and less than 10 ns response characteristics.

Pb(Zr, Ti)O 3 (PZT) heterostructure optical waveguides were grown on low resistivity Nb-doped SrTiO3(100) substrates by solid-phase epitaxy. The propagation loss was reduced to 1.7 dB/cm at the wavelength of 1.3 μm by introducing an epitaxial buffer layer between the PZT waveguide and the Nb-doped SrTiO3 substrate. An electro-optic beam deflector with an indium–tin–oxide prism electrode on the surface of the PZT waveguide showed efficient laser beam deflection as great as 3.3° (58 mrad) by applying 20 V between the prism electrode and the substrate. An index change higher than 0.001 at 5 V and an average apparent electro-optic coefficient larger than 46 pm/V were estimated from the deflection characteristic.

Pb(Zr0.52Ti0.48)O3 (PZT) thin films were crystallized on SrTiO3 (100) and MgO (100) substrates by a sol-gel process using nonhydrolyzed metal methoxyethoxide precursors, spin coating, and rapid thermal annealing. Solid phase epitaxial growth of PZT on SrTiO3 was observed directly from the amorphous phase even at 425 °C. The PZT had a single (001) orientation and rocking curve full width at half maximum (FWHM) less than 0.1°. High-temperature annealing of MgO substrates improved orientation of PZT thin films. Epitaxial crystallization of PZT with a single (001) orientation on the annealed MgO was observed at temperature above 550 °C after the formation of the pyrochlore phase.

The electrooptic behavior of (Pb, La)(Zr, Ti)O3 (PLZT) heterostructure waveguides, including PLZT/Pb(Zr0.95Ti0.05)O3 [PZT (95/5)] and Pb(Zr0.52Ti0.48)O3 [PZT (52/48)]/Pb(Zr0.85Ti0.15)O3 [PZT (85/15)] on Nb–ST substrates was examined. Electrooptic behavior was characterized by fabricating beam deflectors using these heterostructures. The heterostructure waveguides exhibited hysteresis-free electrooptic behavior after the application of initial voltage. The electrooptic behavior of PLZT/PZT (95/5) and PZT (52/48)/PZT (85/15) heterostructure waveguides presented a nonlinear dependence and a linear dependence, respectively. The apparent electrooptic coefficient of the PLZT/PZT (95/5) heterostructure obtained from the linear part of the V–θ characteristic above +7.5 V was 53 pm/V, and that of the PZT (52/48)/PZT (85/15) heterostructure was 37 pm/V. The electrooptic coefficient of the PZT (52/48) waveguide layer using an effective voltage was estimated to be 53 pm/V.

When two electrodes at different temperatures are placed m a reacting flame gas at atmospheric pressure, a potential dfference is estabhshed between them.A. von Engel and J. R. Cozens 1500.

MgO thin films were prepared on Si(100) and GaAs(100) by electron-beam evaporation. MgO thin films with (100) orientation were obtained at 610°C with the deposition rate of 0.5 Å/s, and those with (111) orientation were obtained below 440°C with deposition rate higher than 8 Å/s, on Si substrates. (100) oriented MgO thin films, however, grew on Si at 440°C upon decreasing the deposition rate to 0.3 Å/s. MgO thin films with (100) orientation having cube-on-cube epitaxy were obtained on GaAs substrates at the temperature as low as 280°C even at the deposition rate of 1.4 Å/s.

Control of crystallinity in solid phase epitaxial growth of LiNbO3 thin films derived from methoxyethoxide solution on sapphire substrates has been attempted by investigating growth variables. Crystallization at 700° C for longer than 30 min was necessary for full crystallization of LiNbO3 thin films, although the orientations of the LiNbO3 crystal planes parallel to the substrates were almost independent of crystallization temperature and crystallization time. Layer-by-layer crystallization and preparation of an ultrathin initial layer have been found to be important in the growth of high-quality epitaxial LiNbO3 thin films. X-ray diffraction analysis revealed that perfectly single-plane-oriented epitaxial LiNbO3 thin films, with rocking curve full width at half-maximum of less than 0.07°, were produced on sapphire (001) substrates. Refractive index of 2.24 and optical propagation loss of 3.0 dB/cm were achieved.