Preparation of Zn1−xMgxO films by radio frequency magnetron sputtering

Abstract II–VI widegap semiconductors such as ZnO are widely utilized in various electronic and optical devices. To widen the band gap of ZnO, we conducted a systematic investigation of solid solution thin films of Zn 1− x Mg x O, a group of ternary compounds of the ZnMgO system. We prepared the thin films by radio frequency (RF) magnetron co-sputtering on fused silica substrates at room temperature. The thin films were a single phase of Zn 1− x Mg x O having the basic structure of ZnO at x ≤0.46 and the basic structure of MgO at x ≥0.62, with segregation of the ZnO and MgO phases at x =0.58. The band gap of Zn 1− x Mg x O having the basic structure of ZnO increased from 3.24 eV at x =0 (ZnO) to 4.20 eV at x =0.46. Transmittances of Zn 1− x Mg x O thin films were nearly equivalent to those of ZnO. Zn 1− x Mg x O has a wider band gap than ZnO and can be expected to provide a useful window layer of solar cells that improves the overall efficiency by decreasing the absorption loss.