Effect of the annealing environment on the optical properties of ZnO/GaAs grown by MOCVD

► (A0, X) and DAP transitions at 3.35 and 3.26 eV related to arsenic acceptor. ► Oxygen annealing ambient promotes arsenic acceptor into ZnO films. ► Increase in structural defect lines is related to arsenic incorporation. ► Annealing at optimal temperature of around 550 °C is necessary for arsenic incorporation.