The band gap energy of the Se-rich ZnOxSe1−x depending on composition as well as pressure

A model is developed to describe the band gap energy of the Se-rich ZnOxSe1−x with O content no more than 0.12. It is found that the band gap reduction is mainly due to the decline of the Г conduction band minimum (CBM) of ZnOxSe1−x. As the coupling interaction between the O level and the CBM of ZnSe is not large, the band E+ is hard to be observed. In addition, ZnOxSe1−x needs larger pressure than ZnSe to realize the transformation from the direct band gap to the indirect band gap. It is mainly due to the coupling interaction between the O level and the Γ CBM of ZnSe.