Synthesis of ZnO nanoflower arrays on patterned sapphire by aqueous solutions

Patterned sapphire with frustum of a cone shape is designed to grow ZnO nanoflower arrays in this paper. The ZnO nanostructures are grown by two-step approach, including the synthesis of homo-seed layer and the growth of ZnO nanostructures in aqueous solutions at low temperature. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). ZnO nanostructures are grown along the upper base and sidewall region on the frustum of a cone shaped sapphire forming flower-like morphology as a whole. Micro-Raman spectrum shows the nanoflower arrays are under low tensile stress. Meanwhile, the ZnO nanoflower arrays grown on patterned sapphire show high photocatalytic activity. The large-scale periodical flower-like characteristics make them also potential applications in ultra-sensitive gas sensing, exciton based photonic devices.