Structural and optical properties of (Pb,Ca)TiO₃ thin films prepared by a sol-gel technique

Abstract

Transparent and crack-free calcium modified lead titanate thin films were prepared on platinum-coated silicon and fused quartz substrates by a sol-gel technique. Lead acetate trihydrate, calcium nitrate tetrahydrate and titanium tetra-n-butoxide were used as starting materials. Methanol and ethanolamine were used as solvent and stabilizing agent, respectively. The structural properties of the thin films were studied by x-ray diffraction technique. Optical transmission and absorption properties of the thin films were measured in the wavelength range of 200-1100 nm. The thin films possess good optical transmissitivity. By using an approximate formula, the refractive index and band gap were evaluated. The optical transitions of the thin films are direct in nature. The dispersion relation of refractive index and wavelength follows the single electron oscillation model.