Electronic and optical properties of ZnO thin film under in-plane biaxial strains: Ab initio calculation

The full regions of the electronic and optical properties of in-plane biaxial strained thin film ZnO are studied using pseudopotential plane-wave method. The fundamental band gap at the Γ point increase linearly with the increase of tensile strains, but decreased with the compressive ones. The strains affected the local tetrahedral symmetry, and so the splitting of crystal field energy. The band dispersion relation of the valence band maximum changes with the strains, which means the residual strains have effects on the effective hole mass, thus the transportation properties of the p-type ZnO. The changes tendency of optical properties up to full regions under strains have been shown and discussed.