Effect of oxygen partial pressure on morphology of ZnO nanostructure prepared on Zn films by simple evaporation without any additive

A novel multichip ZnO nanostructure and a classic tetrapod ZnO nanostructure were successfully synthesised by the simple thermal evaporation using a laser molecular beam epitaxy prepared Zn film as grow sites. The morphology of the products could be impacted by adjusting the oxygen partial pressure. The as fabricated multichip ZnO nanostructure consists of a dozen chips, whose root is abroad and has a rod at the end. The structure of the multichip ZnO nanostructure was investigated thoroughly using various analytic techniques. Based on the experimental results, a growth model was proposed to interpret the growth mechanism of the novel nanostructure. An ultraviolet emission band located at 384 nm and a broad green emission band centred at 505 nm were observed at room temperature. Remarkably, the multichip ZnO nanostructures have an enhanced green emission in comparison with those of the tetrapod ZnO nanostructure.