Morphology-controlled growth of tetrapod ZnO nanostructures by direct arc discharge

A novel buttress-root shaped ZnO tetrapod-like nanostructure and a classic tetrapod ZnO nanostructure were synthesized by a direct reaction of high-purity Zn granules with oxygen using an arc discharge method. The morphology of the products could be controlled by adjusting the oxygen partial pressure. The buttress-root shaped tetrapod-like nanostructure contains three triangular nanosheets, the diameters of nanoarms vary between 50 and 80 nm, and the angle between every two arms is about 109.5°. A nanorodcentered growth model has been proposed to explain the novel nanostructure. An ultraviolet (UV) emission band located at 389 nm (3.18 eV) and a broad blue emission band centered at 484 nm (2.57 eV) were observed at room temperature.