Highly c-axis-oriented zinc oxide (ZnO) films with nano-size grains were successfully prepared on sapphire (0001) substrates by polymer-assisted deposition, where the crystallization of the ZnO was realized by a rapid thermal process (RTP). Post-processing conditions played critical roles in the structure, surface morphology, and the photoluminescence (PL) spectra of the films. The post-thermal treatment by RTP enhances the green PL of the ZnO films. Oxygen vacancies induced by the RTP may be related to the green PL from undoped ZnO. (c) 2005 Elsevier B.V. All rights reserved.