Effect of environment and heat treatment on the optical properties of RF-sputtered SnO2 thin films

► The amorphous SnO2 films were RF-sputtered under a mixture of oxygen and argon environment. ► The optical properties of the films are strongly dependent on the deposition environment. ► The change in optical properties is attributed to the change in oxygen vacancy concentration. ► Annealing of the films at 500 °C leads to their crystallization. ► The band gap of the film decreases on crystallization.