Effect of rapid thermal annealing on Mg_x Zn1-x O films prepared by radio-frequency magnetron sputtering

This study investigates the effects of thermal annealing on the MgxZn _1-xO films. MgxZn_1-xO films were deposited by a radio-frequency magnetron sputtering system using a 6 in. ZnO/MgO (80/20 wt %) target. The Hall results, x-ray diffraction (XRD), transmittance, and x-ray photoelectron spectroscopy (XPS) were measured. The XRD results indicate that the appearance of only (111) peaks in the as-grown MgxZn_1-xO film is a sign of the cubic single phase, whereas the appearance of ZnO (002) peaks in MgxZn_1-xO films annealed at 700 and 800 °C confirms the formation of a wurtzite single-phase crystal. The existence of a weak (002)-wurtzite peak besides the (111)-cubic peak indicates the coexistence of two phases. The absorption spectra of MgxZn_1-xO annealed at 700 and 800 °C show two stages at wavelengths of 357 and 261 nm. The XPS spectra of MgxZn _1-xO films were also demonstrated. The results of this study show that the ZnO films were separated from MgxZn_1-xO films after higher thermal annealing.