Influence of Cu dopant on the structure and optical properties of ZnO thin films prepared by MOCVD

ZnO:Cu thin films were prepared on the sapphire substrate using low-pressure metal organic chemical vapor deposition system. The influence of Cu dopant on the structure and morphology, electrical and optical properties of ZnO was investigated. Scanning electron microscope results showed that the smooth surface morphology was made up of evenly diameter nanorod, with complete hexagonal structure at some doping point. Low temperature photoluminescence results indicated that Cu dopant introduced more than one acceptor energy level in the energy gap and the energy levels were multiple and complicated. The presence of donor and acceptor pairs suggested that acceptors were really incorporated into ZnO, and it was proposed to be Cu1+. These results confirmed that moderate Cu-dopant in ZnO could improve the optical properties and it extended a rich picture of the bound excitons emission.