Effect of zinc sources on the morphology of ZnO nanostructures and their photoluminescence properties

The morphology and photoluminescence properties of ZnO nanostructures synthesized from deferent zinc sources by a vapor deposition process were investigated. The zinc sources involved pure zinc, ZnO, and ZnCO3 powders, respectively. It was found that the zinc sources have a strong effect on the morphology of the ZnO nanostructures. For the pure zinc and ZnO sources, uniform ZnO nanowires and tetrapods are obtained, respectively. However, in the case of the ZnCO3 source, the products are nanowire-tetrapod combined nanostructures, in which ZnO nanowires grow from the ends of tetrapod arms. The morphology differences of these products may be mainly concerned with the yield and constituents of the corresponding zinc vapor. Photoluminescence measurements show that the nanowires have a relatively stronger near-band UV emission than the other products. The strongest green-light emission from the tetrapods implies that more defects exist in the tetrapods. An evident peak at 430 nm is found in the spectrum of the nanowire-tetrapod combined nanostructures, which may be caused by oxygen-depletion interface traps.