Luminescent properties of ZnO thin films grown epitaxially on Si substrate

Abstract ZnO thin films were grown on Si(1 1 1) substrates by employing an epitaxial ZnS thin film as a buffer layer. The structural and luminescent properties of the ZnO thin films have been investigated in view of the application to opto-electronic devices due to near-ultraviolet emission by exciton the binding energy of which is about 60 meV. When the epitaxial ZnS buffer layer was grown on the Si(1 1 1) substrate at a substrate temperature of 200°C by electron beam evaporation, the epitaxial ZnO film was successfully grown on the ZnS/Si(1 1 1) layer with the orientation of (0 0 0 2), [1 1 2 0] ZnO∥(1 1 1), [1 1 0] ZnS∥(1 1 1), [1 1 0] Si(1 1 1) at a substrate temperature of 400°C. An excitonic emission with a peak at 3.35 eV at 20 K was successfully obtained by exciting at 325 nm of He–Cd laser.