Optical Properties of Nano-Crystalline Zirconia Thin Films Prepared at Different Post-Oxidation Annealing Times

The zirconia (ZrO₂) is one of the transition-metal oxides with most excellent optical properties which thus attracts great attention in optical engineering. A variety of methods were used for deposition of ZrO₂ thin films on different substrates. In the present work, homogenous, transparent nanocrystalline zirconia thin films were grown by thermal oxidation of zirconium (Zr) thin films deposited on quartz substrate using DC magnetron sputtering technique. The objective of this study is to reveal the effect of thermal oxidation time on structural and optical properties of deposited films. The XRD results revealed the formation of single phase ZrO₂ with tetragonal structure in the films at different thermal oxidation times. The optical constant of ZrO₂ thin films was calculated from the UV-visible transmission spectra. It was found that the increase of thermal oxidation time leads to the increase of transmittance and optical band gap energy of the films. The AFM results showed that thermal oxidation time influences the surface morphology of the films.