Fabrication and characterization of flower-like CuO–ZnO heterostructure nanowire arraysby photochemical deposition

Abstract

A simple two step solution-based method was applied to fabricate CuO–ZnOheterostructured nanowire (NW) arrays. First, ZnO nanowires were grown ona Si substrate using the ammonia solution hydrothermal reaction. Afterwards,flower-like CuO crystals were photochemically deposited on the tip of the ZnO NWs,using ultraviolet (UV) light (312 nm wavelength) irradiation at room temperature.The morphology of the CuO was controlled by reaction time, density of ZnONWs, and concentration of the solution. Because the deposited CuO is p-type andhas narrow band gap properties, CuO–ZnO heterostructured NWs exhibited astable p–n junction property and good ability to absorb visible light. Throughinvestigation of UV light-triggered reaction phenomena, we found that the production ofOH − from the photocatalytic process on the surface of ZnO NWs plays a critical role in the CuOdeposition mechanism.