Isochronal Effect of Optical Studies of TiO2 Thin Films Deposited by Spray Pyrolysis Technique

The TiO2 films were deposited using Spray Pyrolysis Technique at 300 °C. The as deposited TiO2 films were annealed isochronally at temperatures of 400 °C, 500 °C and 600 °C under air ambient at constant time duration of 30 minutes. The surface morphology show a uniform distribution of TiO2 nano particles having spherical shape grain and estimated values of grain sizes increase from 13 to 27 nm with increase in annealing temperature, this is due to the shrinkage and densification as a result of elimination of porosity inside TiO2 thin films. X-ray diffraction result reveals that obtained TiO2 thin films exhibit anatase phase. From EDAX spectrograph of the TiO2 films, the chemical composition was obtained which showed 1:2 for Titanium (Ti):Oxygen (O). The optical parameters such as refractive index, extinction coefficient, real and imaginary part of the dielectric constant, energy band gap were calculated from transmittance spectra recorded using UV-Visible spectrophotometer in the wavelength range 350–1200 nm, where as the thickness of the TiO2 thin films was estimated from reflectance spectra. The obtained optical parameters are observed to decrease with increasing heat treatment due to the increase in grain size. TiO2 films showed with improved anatase phase with increasing heat treatment and are suitable for sensor application