Effect of O2 in O2/Ar Gas Mixture on Morphological and Optical Properties of TiO2 Thin Films Deposited by DC Cylindrical Magnetron Sputtering

Abstract

TiO2 films have been deposited on BK7 substrates by DC cylindrical magnetron sputtering setup in ambient temperature. The samples were fabricated at various O2/Ar reactive gas mixtures. The effects of changing O2 amount in O2/Ar reactive gas mixture on structural, morphological and optical properties of films were studied. The thickness of films was measured by surface profile meter. Thickness of films decreases with increasing the O2 amount in gas mixture. XRD studies shows that the films are amorphous. Atomic Force Microscopy was used to evaluate and compare the surface roughness and morphologies. The optical properties (transmission and reflection) of the samples were measured by UV–Vis–NIR spectrophotometer. Results show that increasing the O2 amount in O2/Ar mixture changes the surface morphologies and optical properties of films. All films exhibit a transmittance higher than 65 % in the visible region. The band gap of films was calculated from the optical measurements. The band gap of TiO2 thin films increases from 3.471 to 3.526 for different O2/Ar amounts.