First-principles calculation of electronic structures and optical properties of wurtzite InxAl1-xN alloys

The electronic structures and optical properties of wurtzite InxAl1-xN have been calculated using a first-principles self-consistent method. The calculated lattice constants and band gap bowing parameter are in good agreement with the experimental results and/or values given by other calculation methods. It is interestingly found that the peaks of total density of states (TDOS) in the conduction band have a tendency of shifting to the lower energy as In concentration increases in InxAl1-xN; while in the deep valence band, the peak splits into three peaks. The optical properties such as the dielectric function, reflectivity, absorption coefficient, refractive index, and electron energy-loss function are also presented. The main peak in imaginary part of dielectric function spectrum, the absorption edge and the peak in L(omega) spectrum are found to have a remarkable red-shift as In mole fraction increases. Furthermore, the optical properties of wurtzite InxAl1-xN are discussed based on the band structures and density of states (DOS) analysis.