Zinc vacancy-related complex and its abnormal photoluminescence in Zn+-implanted ZnO single crystals

Zinc vacancy (VZn) plays key roles in the optical and electrical properties of ZnO, but its behaviors are not fully understood. Here we report the formation and abnormal photoluminescence (PL) of VZn-related complex in Zn+-implanted ZnO single crystals. With increasing excitation density, we observed a new and gradually increased broad emission around 550 nm. The 550 nm emission is unexpectedly invisible under low power level excitation, indicating the lower priority of recombination of the related defect centers. Electron paramagnetic resonance (EPR) results suggest the formation of VZn-Zni complex after implantation, which is responsible for the abnormal PL properties.