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

Abstract

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 650°C 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 μC cm−2 and a coercive field of 132.1 kV cm−1.