双轴应变AlxGa1-xAs光电性质的第一性原理研究OA

AlxGa1-xAs(x=0～1),an important Ⅲ-Ⅴ group semiconductor,is widely used in optoelec-tronic devices.The strain induced by annealing or lattice mismatch during its fabrication and integra-tion significantly affects both the material itself and the overall device performance.Therefore,the op-toelectronic properties of AlxGa1-xAs under biaxial strain(—3％～+3％)were systematically investigated using first-principles calculations.First,a special quasi-random structure(SQS)model was constructed,and the functionals for subsequent property calculations were selected by comparing the lattice constants obtained with different functionals.Based on the atomic structures relaxed using the SCAN functional,the effective band structures and band gaps were obtained by combining the MBJLDA functional with band structure unfolding.The results show that both strain and Al content influence the energies of the conduction band at the T and X points.When x≤0.75,the material possesses a direct band gap,and compressive strain can induce a transition to an indirect band gap.Conversely,when x≥0.875,the material has an indirect band gap,and tensile strain can induce a transition to a direct band gap.Optical property calculations based on the PBEsol functional reveal that the Al content governs the absorption edge position,whereas the strain affects the position(tensile strain leads to redshift,compressive strain leads to blueshift)and intensity of the absorption peaks.