Optics and spectroscopy

Abstract

The effects of Cd_Zn substitution and oxygen vacancy (V_O) on the structural, electronic, and optical properties of ZnO have been investigated using density functional theory (DFT) with a 3 × 3 × 3 supercell model. V_O generates donor levels near the conduction band minimum, thereby enhancing n‑type conductivity, while Cd_Zn modifies the valence band through Cd-4d/O-2p hybridization. The combined system is characterized by intensified intermediate levels near the band gap, increased spin asymmetry, and a red shift of the absorption edge. The results obtained demonstrate that the optoelectronic properties of ZnO can be systematically tuned through defective engineering.