Simple fabrication and improved photoresponse of ZnO–Cu2O core–shell heterojunction nanorod arrays

ZnO–Cu2O core–shell nanorod heterostructures were synthesized by a proposed solution process. High-resolution transmission electron microscopy shows the Cu2O nanoshells with a thickness of around 10 nm are constructed of single-crystalline nanoparticles with a diameter of around 5 nm capped on the surface of ZnO nanorods. Photoluminescence measurements show that the green emission of ZnO nanorods was eliminated by capping with Cu2O nanoshells. An improved photoresponse of ZnO–Cu2O heterojunction nanorods with ultrafast and extended high sensitivity from UV to the visible range is demonstrated. These heterostructures are promising for photosensing and solar energy applications.