The photoluminescence (PL) emission properties of ZnO films obtained on quartz glass substrate by the oxidation of Zn films were studied. The strong single violet emission centering about 413-424 nm was observed in the room temperature PL spectra of the ZnO films. The intensity of violet emission increased and the peak position shift from 424 to 413 nm with increasing oxygen pressures. The violet emission was attributed to the electron transition from the valence band to interstitial zinc (Zn-i) level under low oxygen pressure conditions (50-500 Pa). Under high oxygen pressure conditions (5000-23,000 Pa), both interstitial zinc (Zn-i) and zinc Vacancy (V-Zn) were thought to be responsible for the violet emission. (c) 2005 Published by Elsevier B.V.