Band anticrossing in ZnOSe highly mismatched alloy.

ZnO_xSe_1−x layers with x ≤ 1.35% were studied by photoreflectance at 80 K. Careful analysis of the PR spectra allowed the identification of the optical transitions from the valence band to the E₋ and E₊ subbands originating from the band anticrossing interaction between the resonant oxygen level and the conduction band of the ZnSe host. In addition, it was possible to resolve a strain-induced splitting of the valence band into the heavy- and light-hole subbands. The strain changes from compressive to tensile with increasing oxygen concentration for these ZnO_xSe_1−x layers grown on a GaAs substrate. [ABSTRACT FROM AUTHOR]