Effects of Cu, Zn Doping on the Structural, Electronic, and Optical Properties of α-GaO: First-Principles Calculations.

The intrinsic n-type conduction in Gallium oxides (GaO) seriously hinders its potential optoelectronic applications. Pursuing p-type conductivity is of longstanding research interest for GaO, where the Cu- and Zn-dopants serve as promising candidates in monoclinic β-GaO. However, the theoretical band structure calculations of Cu- and Zn-doped in the allotrope α-GaO phase are rare, which is of focus in the present study based on first-principles density functional theory calculations with the Perdew-Burke-Ernzerhof functional under the generalized gradient approximation. Our results unfold the predominant Cu and Zn oxidation states as well as the type and locations of impurity bands that promote the p-type conductivity therein. Furthermore, the optical calculations of absorption coefficients demonstrate that foreign Cu and Zn dopants induce the migration of ultraviolet light to the visible-infrared region, which can be associated with the induced impurity 3d orbitals of Cu- and Zn-doped α-GaO near the Fermi level observed from electronic structure. Our work may provide theoretical guidance for designing p-type conductivity and innovative α-GaO-based optoelectronic devices.