ZnO thin films were deposited on sapphire (0 0 0 1) substrates with various thicknesses using a pulsed-laser deposition (PLD) technique in order to investigate the structural and optical properties of the films. The deposition conditions were optimized for UV emission property. The structural and optical properties were characterized with XRD and photoluminescence (PL). The increase in ZnO film thickness results in the improvement of the structural and optical properties. This enhancement could be due to the decrease of strain at the interface between ZnO film and sapphire substrate by the increase of film thickness. (C) 20021 Elsevier Science B.V. All rights reserved.