Synthesis of gear-shaped ZnO microwires by chemical vapour deposition

A tail-like cluster composed of zinc oxide (ZnO) microwires had been synthesised by a simple chemical vapour deposition method at high temperature. Most of the microwires exhibit an interesting gear-shaped microstructure. A new model is proposed to interpret the growth mechanism of gear-shaped ZnO microwires. It is suggested that the gear-shaped ZnO microwires are formed by a coalescence of ZnO fine wires. A distinct ultraviolet emission band centred at 389.8 nm is observed in the photoluminescence spectrum. The gear-shaped microwires with high surface-to-volume ratio are expected to improve the physical, chemical and biological sensitivity of ZnO, which will be helpful for the further application of ZnO in the field of sensor devices.