A ZnO epitaxial thin film could be formed by oxidation of a ZnS epitaxial thin film on a Si substrate. The orientation relation of the ZnO film was (0002), [11-20] ZnO//(111), [1-10] Si. ZnS films was oxidized from its surface to the Si substrate and gradually changed to ZnO film. ZnS film was completely changed to ZnO by annealed at 720oC for 10 min. By excess annealing above 30 min, an intermediate layer was formed at the interface between the ZnO layer and Si substrate. Exciton emission become dominant and visible emission disappeared by annealing the film at 800oC over 5 h, because of compensation of oxygen by the annealing.
