Mechanism study on enhancing solar-blind photoelectric performance of β-Ga2O3 via Zn-P co-doping combined with strain regulation

Abstract Owing to its wide bandgap characteristics, β-Ga₂O₃ demonstrates significant potential for applications in solar-blind ultraviolet photoelectric devices. However, substantial challenges remain in achieving effective p-type doping in intrinsic β-Ga₂O₃ and overcoming the limitations in carrier transport properties. This work employs first-principles calculations to systematically investigate the modulation mechanisms of Zn-P co-doping in the presence of oxygen vacancy (VO) conditions on the structural stability, electronic structure, dielectric properties, and carrier transport characteristics in β-Ga₂O₃. The results demonstrate that in the presence of VO, Zn preferentially substitutes the tetrahedrally coordinated Ga site (denoted as Ga1) adjacent to the oxygen vacancy, while P preferentially occupies the neighboring O site (O1). The resulting doped configuration exhibits excellent thermodynamic and kinetic stability, particularly under Ga-rich growth conditions. The synergistic interaction between VO and Zn-P co-doping introduces shallow acceptor levels (0.16–0.41 eV above the valence band maximum (VBM)) within the band gap, significantly narrows the band gap (e.g., the VO-ZnGa-2PO system exhibits a reduced band gap of 3.41 eV), and modulates the charge distribution to enhance carrier delocalization. Analysis of the dielectric function reveals that the co-doped systems exhibit substantially enhanced optical absorption and photoelectric conversion efficiency within the solar-blind ultraviolet region (200–280 nm). The VO-ZnGa-2PO configuration demonstrates the most superior performance, though attention should be given to the potential limitation in response speed induced by excessive enhancement of the real part of the dielectric function. Investigations on carrier transport properties reveal that Zn-P co-doping effectively optimizes the deformation potential and effective mass, leading to a remarkable enhancement in carrier mobility. Specifically, compared with β-Ga₂O₃, the VO-ZnGa-2PO system exhibits a 4.5-fold increase in hole mobility and a 74% improvement in electron mobility. The application of − 5% biaxial compressive strain further reduces the hole effective mass, leading to a significant enhancement of hole mobility along the [010] direction to 187.51 cm²V⁻ ¹s⁻ ¹ in this system. This study provides theoretical foundations and technical pathways for achieving effective p-type conductivity regulation and performance optimization in β-Ga₂O₃-based solar-blind photoelectric devices.