First principles study on electronic and optical properties of Al_xGa_(1-x)N and In_yGa_(1-y)N

摘要

The band structure, density of states of AlxGa1-xN and InyGa1-yN was performed by the first-principles method within the local density approximation. The calculated energy gaps of the AlN, Al0.5Ga0.5N, GaN, In0.5Ga0.5N and InN were 5.48, 4.23, 3.137, 1.274 and 0.504 eV, which were in agreement with the experimental result. The dielectric functions, absorption coefficient and loss function were calculated based on Kramers-Kronig relations. Further more, the relationships between electronic structure and optical properties were investigated theoretically. For AlxGa1-xN and InyGa1-yN materials, the micromechanism of the optical properties were explained.