Fabrication of ultrathin ZnO nanowires and their photoluminescence properties

Ultrathin ZnO nanowires have been fabricated by a vapor-phase transport process via the vapor-liquid-solid mechanism. The average diameter of the nanowires is about only 10 nm and the length is up to several micrometers. The experimental results show that the growth of the nanowires is very sensitive to the temperature, catalyzer materials, the content of oxygen in the carrier gas, and the gas pressure. The diameter of the nanowires is directly determined by the size of eutectic alloy droplets related to the thickness of Au catalyzer film and the gas pressure. Ultrathin ZnO nanowires can only be synthesized at a certain pressure of about 300 Torr and the temperature in the range from 450-500 °C when a layer of 20 nm Au catalyzer film is employed. Photoluminescence spectrum of the ultrathin ZnO nanowires is also measured, and an intensive ultraviolet light emission centered at 389 nm has been observed.