The preparation of homogeneous single-phase ZnSe films using a two-stage selenization process is demonstrated. Vacuum-evaporated zinc precursor films (stage 1) are selenized in a specially designed reactor, using elemental selenium vapour as the reactant (stage 2). The ZnSe films are polycrystalline with a cubic structure, as confirmed by X-ray diffraction. The films are optically transparent and have an optical band gap of 2.65 +/- 0.05 eV, confirming the formation of the wide band gap semiconductor. The ZnSe films have very small crystallites (size <0.3 mu m) and their morphology is determined by that of the deposited zinc film. X-ray photoelectron spectroscopy analysis of the films shows a chemical shift of approximate to 0.9-1.0 eV for selenium (3d), which suggests a transfer of electronic charge to selenium. This and the observed Auger parameter of 2011.1 eV for Zn (2p(3/2)) confirm the formation of ZnSe. The absence of multiple phases is ascertained by the sharpness of the X-ray photoelectron spectroscopy peaks.