Effect of Mg/Zn RF power ratio and substrate temperature on optical and structural properties of RF co-sputtered MgxZn1-XO alloy thin films

We report the growth of MgZnO thin films on Si (100) substrates using rf co-sputtering technique. It is found that structural and optical properties of MgZnO thin films highly depend on Mg/Zn rf power ratio and substrate temperature. We observe an increase in band gap of MgZnO thin films from 3.3 eV to 5.9 eV with increasing Mg/Zn rf power ratio from 0 to 2.22 at 400 °C substrate temperature. Whereas, XRD studies show a structural phase transition of MgZnO films from hexagonal wurtzite via mixed phase region of both wurtzite and cubic phases to cubic phase with increase in Mg/Zn rf power ratio. As the substrate temperature increases from 400 °C to 700 °C, the MgZnO films in the mixed phase region shows single cubic phase.