Novel ultraviolet photoluminescence of ZnO/ZnGa2O4 composite layers

ZnO/ZnGa2O4 composite layers were synthesized by simple thermal oxidation of ZnS substrates with gallium in the air. The continuous-wave and time-resolved photoluminescence measurements for the composites were performed at room temperature. It is found that the visible deep level emission from ZnO in ZnO/ZnGa2O4 composite layer was almost suppressed. In addition, the UV emission with long lifetime was also observed in comparison with that of pure ZnO layer without ZnGa2O4.