Optical and electrical properties of sol–gel derived thin films of PbTiO3

Thin films of polycrystalline PbTiO3 were prepared by sol–gel process—spin coating method. The substrates used were fused silica and stainless steel. The effect of post-deposition annealing on the electrical properties was analysed. Crystalline phase of PbTiO3 can only be obtained when the annealing temperature was higher than 500 °C. The electrical measurements were conducted on metal-film-metal capacitors. Films annealed at 600 °C exhibited crystallinity with perovskite phase, a dielectric constant of 125 and a dissipation factor of 0.035 at 1 kHz. Current–voltage (I–V) characteristics were found to be ohmic at lower fields and space charge limited current (SCLC), controlled by traps at higher fields. Transmission spectra of the films deposited on fused silica were recorded and from this, refractive index, extinction coefficient and thickness of the films were calculated. The refractive index was found to be in the range 1.90–2.25 for different wavelengths (300–900 nm).