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 degrees 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 degrees C to 700 degrees C, the MgZnO films in the mixed phase region shows single cubic phase.