Effect of MgO on the enhancement of ultraviolet photoluminescence in ZnO

By glycine-nitrate combustion route and followed by 900°C annealing in air, ZnO–MgO nanocomposite with heterojunction-like structures between ZnO and MgO phase was successfully produced. The ultraviolet photoluminescence band from ZnO is enhanced by the incorporation of MgO, as compared to the pure ZnO synthesized via the similar route. The charge transfer required by electronic equilibrium across the junction creates an electron depletion region in ZnO phase, which greatly changes the electron states of visible emission-related defects, as a result, the band-edge emission is enhanced while the visible emission in ZnO is suppressed. This mechanism may provide an effective way to modify the emission property of nanomaterials.