ZnO epitaxial thin films could be formed by oxidation of ZnS epitaxial thin films deposited on Si substrates by electron-beam evaporation. The orientation relation of the ZnO film was (0002), [11-20]ZnO//(111), [1-10]Si. The ZnS films were oxidized from its surface toward the surface of the Si substrate gradually. The ZnS film with a thickness of about 100 nm was completely changed to ZnO by annealing at 720 degrees C for 10 min in O-2 atmosphere. By excess annealing, longer than 30 min, an intermediate layer was formed at the interface between the ZnO layer and Si(111) substrate. Exciton emission with a peak at 3.27 eV from ZnO became dominant and visible emission due to oxygen vacancy in ZnO disappeared by the annealing of the film at 800 degrees C for 5 h in O-2 flow. (c) 2004 Elsevier B.V. All rights reserved.