Effects of oxygen/argon ratio and annealing on structural and optical properties of ZnO thin films

► ZnO thin films were prepared at various O2/Ar ratios by RF magnetron sputtering. ► Green emission band observed at the ZnO films with O2/Ar flow ratio of 35/35 was attributed the OZn and Oi-related emission. ► Moderate annealing temperature can increase the transmittance and PL emission of ZnO films.