Hole traps and Cu-related shallow donors in ZnO nanorods revealed by temperature-dependent photoluminescence

This work presents positive experimental evidence for the hole traps in ZnO nanorods, which take part in recombination and change the thermal quenching of Cu-related green emission. The evolution of Cu impurity upon annealing, as well as the formation of Cu-related shallow donors with an energy level of similar to 0.11 eV are also indicated by temperature-dependent photoluminescence.