Determination and analysis of dispersive optical constant of TiO ₂ and Ti ₂ O ₃ thin films

Electron beam evaporation technique was used to prepare TiO ₂ and Ti ₂ O ₃ thin films onto glass substrates of thicknesses 50, 500 and 1000 nm for each sample. The structural investigations revealed that the as-deposited films are amorphous in nature. Transmittance measurements in the wavelength range (350-2000 nm) were used to calculate the refractive index n and the absorption index k using Swanepoel's method. The optical constants such as optical band gap E _g ^opt , optical conductivity σ _opt , complex dielectric constant, relaxation time τ and dissipation factor tan δ were determined. The analysis of the optical absorption data revealed that the optical band gap E _g was indirect transitions. The optical dispersion parameters E _o and E _d were determined according to Wemple and Didomenico method.