Controllable growth of ZnO–ZnSe heterostructures for visible-light photocatalysis

Abstract

One-dimensional ZnO-core–ZnSe-shell heterostructures with different ratios of the two components were fabricated via a two-step chemical vapor deposition process at different temperatures of the substrates. The scanning electron microscopy images show that numerous ZnSe nanoparticles with different sizes are uniformly distributed on the surface of ZnO nanobelts. The X-ray diffraction patterns confirm that the heterostructures are composed of wurtzite ZnO and cubic ZnSe. The intensity ratios of visible emission to ultraviolet emission (from 0.15 to 14.50) are tuned by the change in the components due to the type-II energy band alignment structure. The photoluminescence mechanism of the ZnO–ZnSe heterostructures is proposed. In addition, the absorption of ZnO–ZnSe heterostructures extends from the ultraviolet region to the visible region, compared with the pure ZnO. The ZnO–ZnSe heterostructures with type-II energy band alignment show a high photocatalytic activity.