The optical and vibrational properties of dominant defects in undoped ZnO: A first-principles study

Abstract

Studying native defects in semiconductors is of crucial importance for understanding the nature of defects as well as for controlling the quality of the as-grown materials. In this work, we present theoretical studies on the electronic structures, optical and vibrational properties of the dominant defects (VO, HO and VZn) in nominally undoped wurtzite ZnO. We find that the imaginary parts of dielectric functions and absorption coefficient arising from these defects show different features. Typically, the existence of VO in bulk ZnO makes it transparent for visible light but not for violet light. For the cases of both HO and VZn, there are strong infrared absorptions. On the other hand, the vibrational frequencies associated with these defects are calculated, from which some typical vibrational modes relevant to the defects are revealed.