P-passivated nanocrystalline ZnO films on InP substrates were prepared by thermal oxidation of Zn films. By a simple thermal annealing cycle process, uniform photoluminescence (PL) samples with controllable visible emission and intense UV emission were obtained at different annealing conditions. Through a detailed study of the photoluminescence spectra of P-passivated nano-ZnO films vs the annealing-temperature and annealing-time, it is shown that applying different annealing time or temperatures provides a very practical technique to control the deep-level defect emission. A core-shell structure model of the surface passivation was helpfully used to discuss the P-passivation mechanism. (C) 2004 Elsevier B.V. All rights reserved.