Effect of Annealing Time on Physical Properties of TiO2 Thin Films Prepared by RF Magnetron Sputtering Technique

Abstract

The rf magnetron sputtering technique was utilized to prepare titanium dioxide (TiO₂) thin films on glass substrates. These films were annealed for one hour at temperatures of 400, 500 and 600°C. The UV-visible-NIR spectrophotometry was used to characterize the prepared films in order to determine their optical constants. The Field-emission scanning electron microscopy (FE-SEM) was used to determine the film thickness. The results showed that the transmittance of these films increases as the annealing temperature is increased. In the visible region of spectrum, the index of refraction of the prepared films was ranging from 2.22 to 1.2. The extinction coefficient was very low in the visible region and it increased with increasing annealing temperature. The gas sensitivity of TiO₂ films increase in the temperature range of 200-1400°C even at low NO₂ concentrations. The film annealed at 600°C shows high sensitivity to NO₂ gas at ambient temperature and this sensitivity increases at operation temperature of 100°C.