A New Luminescent Phenomenon of ZnO Due to the Precipitate Trapping Effect of MgO

A new luminescent phenomenon was found in the ZnO-MgO system. After Zn _1-xMg_xO (x < 0.15) pellets were sintered in an open crucible below 1600 °C or in a sealed crucible below 1300 °C, they emitted green lights upon excitation of ultraviolet (UV) lights and there was no persistent luminescence (afterglow) after the excitation light was cut off. After Zn_1-xMg_xO (0.02 ≤ x < 0.15) pellets were sintered in a sealed crucible above 1300 °C, they emitted bright orange lights induced by UV excitation and showed a long orange afterglow, which persisted for about 10 min in the darkness after the removal of irradiating light. A precipitate trapping effect of MgO on ZnO luminescence was found, which resulted in the long orange afterglow. This report may shed more light on the luminescent mechanism of ZnO and supply useful information for understanding the luminescent properties of the ZnO-MgO system intensively.