Band-gap energies of sol-gel-derived SrTiO3 thin films were studied in terms of annealing temperature and film thickness. The band-gap energies of highly crystallized films were comparable to those of single crystals reported, whereas for poor-crystallized films, their band-gap energy values were much larger than those of single crystals. The larger band-gap energy shift was believed to be mainly due to both quantum size effect and existence of amorphous phase in thin films. The band-gap energies also showed a strong dependence on film thickness. There was a critical film thickness (～200 nm), above which the films had band-gap energies close to those of crystals or bulks, but below that, the values shifted largely, which can be attributed to the influence of crystallinity of thin films. Such a thickness effect of band-gap energy should be of high interest in optical device applications.

Ferroelectric (Bi,La) 4Ti3O12 (BLT) thin films with different Bi2O3 template layers were prepared on Pt/Ti/SiO2/Si substrates by a chemical-solution deposition method. The BLT films with a thin Bi2O3 bottom layer and those with a thin Bi2O3 intermediate layer had a (117) preferentially oriented growth after annealing at 750°C, while those with a thin Bi2O3 upper layer and those without a Bi2O3 template layer exhibited a high c-axis orientation. The surface morphologies changed with different preferential orientations. The electrical measurements showed that the use of Bi2O3 template layers improved significantly the P–E hysteresis loops of BLT thin films. The remanent polarization (2Pr) and coercive field (Ec) values of BLT films without a Bi2O3 template layer, with a Bi2O3 upper layer, with a Bi2O3 bottom layer, and with a Bi2O3 intermediate layer annealed at 750°C were 10.8, 29.12, 26.17, and 19.67mC/cm2; 79.0, 74.5, 75.5, and 76.3kV/cm, respectively, at an applied electric field of 350 kV/cm. The dielectric constants and dissipation factors were 184, 303, 243, and 217; 0.036, 0.044, 0.039, and 0.039, respectively, at the frequency of 100 kHz, for these BLT films without a Bi2O3 template layer, with a Bi2O3 upper layer, with a Bi2O3 bottom layer, and with a Bi2O3 intermediate layer. All the capacitors with Bi2O3 template layers showed good polarization fatigue characteristics at least up to 331010 bipolar pulse cycles and excellent retention properties up to 33104s.

Epitaxial and oriented K(Tao0.65Nb0.35)O3 thin films were prepared by the sol-gei method, using metalorganic compounds. The thin films were characterized by X-ray diffraction (XRD), and reflection high energy electron diffraction (RHEED). The mechanism of orientation of the K (Ta0.65Nb0.35) O3 films is discussed.

All-epitaxial (Bi,La) 4Ti3O12 (BLT) /Pb(Zr,Ti) O3(PZT)/(Bi,La) 4Ti3O12 trilayered ferroelectric thin films were prepared on SrRuO3 sSROd-covered SrTiO3s011d substrates by pulsed-laser deposition. Epitaxial relationships were identified to be BLT (118) iPZT (011) iSrTiO3(011), and BLTf1(1)0g iPZTf100g iSrTiO3f100g. Atomic force microscopy observation of the surface showed that the upper BLT layer is composed of rod-like grains. Cross-sectional transmission electron microscopy investigations revealed ferroelectric 90

Calcium modified lead titanate sol was synthesized using lead acetate trihydrate, calcium nitrate tetrahydrate and titanium tetra-n-butoxide as starting materials, methanol and ethanolamine were elected as solvent and stabilizing or complexing agent, respectively. (Pb0.76Ca0.24)-TiO3 thin films were prepared on platinum-coated silicon and fused silica substrates with the solution using the pinning method. The surface morphology and crystal structure, surface compositions and chemical tates, electrical and optical properties of the thin films were investigated. The films have good composition homogeneity and thickness uniformity. The dielectric constant and dissipation factor of 1 kHz at room temperature were found to be 280 and 0.027, respectively, for thin films with 0.5mm hickness annealed at 6008C for 1 h. The remanent polarization and coervive field were 15 mC/cm2 and 64 kV/cm, respectively. The thin