First-Principles Study of the Electronic Structure and Optical Properties of Sn-Cl Co-doped β-Ga2O3

This paper systematically investigates the influence of different Sn-Cl co-doping concentrations on the electronic structure and optical properties of beta-Ga2O3 by employing density functional theory (DFT) calculations based on the generalized gradient approximation with Hubbard correction (GGA+U). The results demonstrate that the co-doped systems exhibit excellent thermodynamic stability under oxygen-rich conditions. The synergistic incorporation of Sn4+ and Cl- ions induces microstructural lattice expansion and bond-length adjustments, effectively introducing shallow energy states, significantly reducing the bandgap, and enhancing carrier activity. Particularly, at a doping concentration of 2.5 at.%, the system displays metal-like properties. Furthermore, at doping levels of 1.67 at.% and 2.5 at.%, the materials show remarkable optical absorption performance spanning the visible to ultraviolet region and exhibit notably low reflectivity, with significantly improved optical responses in the spectral range of 150-500 nm, while maintaining structural stability. This study provides theoretical guidance for tuning and optimizing the optoelectronic properties of beta-Ga2O3, offering important reference value for potential practical applications.