Temperature dependence on optical properties of sr doped BaTiO < inf > 3 < /inf > thin films by vacuum evaporation method

Abstract

Strontium doped Barium titanate nano powders were prepared by the wet chemical method using the starting materials barium chloride (BaCl2), titanium dioxide (TiO2), strontium carbonate (SrCO3) and oxalic acid with high calcinations temperatures. The prepared nano powders were thermally grown onto well cleaned glass substrates under the vacuum of 10-5 torr, using 12A4 Hind Hivac coating unit. The X-ray diffraction patterns revealed that Sr doped BaTiO3 nanoparticles possess tetragonal structure and the deposited films were polycrystalline in nature. Absorption coefficient, extinction coefficient, optical band gap and refractive index of films were estimated from optical transmittance spectrum. The extinction coefficient and refractive index of the BaTiO3 thin films increases with increasing annealing temperature. The optical band gap energy value decreases with increase of annealing temperature.