Thin polycrystalline ZnO films were grown on silicon substrates by dc reactive magnetron sputtering using zinc oxide targets. The quality of the ZnO layers was assessed by X-ray diffraction (XRD), atomic force microscopy, Raman scattering, and photoluminescence measurements. The XRD studies and Raman studies revealed that the ZnO films crystallize in the wurtzite structure. Room temperature photoluminescence spectra consisted of a narrow near-band-edge ultraviolet band and a broad defect-related green band with peak positions at 380 and 516 nm, respectively. The main goal of the work was to define the growth conditions to prepare zinc oxide films with adequate properties to be used in electroluminescent devices. The films exhibited the best surface appearance with a 40:1 argon/oxygen flow rate, a total pressure of 1.5×10−3 mbar, and a substrate temperature of 230 °C. The structural and luminescence properties improved noticeably with the thermal annealing processes at 800 °C for 1 h.