Crystallization and optical properties of sol-gel-derived PbTiO3 thin films

PbTiO3 (PT) thin films were prepared on ZrO2, SrTiO3, thermally oxidized silicon, and fused silica substrates by a simple sol-gel technique. The crystallization and optical properties of the thin films were investigated. The PT films on ZrO2 and SrTiO3 substrates have a c-axis preferential orientation, whereas the films on thermally oxidized silicon and fused silica substrates are slightly a-axis oriented. The thin films exhibited good optical transmittivity. and had optical direct transitions. The band gap energy of the film annealed at 650degreesC was 3.60 eV, which is comparable to those of PT polycrystalline ceramic bulk and films. The thin films on Pt/Ti/SiO2/Si substrates exhibited a ferroelectric hysteresis loop with a remanent polarization of 17.1 muC cm(-2) and a coercive field of 132.1 kV cm(-1).