Calculation of electronic and optical properties of surface InxGa1−xP and indium-gradient structure on GaP (0 0 1)

Electronic and optical properties such as the density of states, dielectric function, absorption, reflectivity, loss function and refractive index of surface InxGa1−xP(0 0 1) are investigated first time with first principle methods based on plane-wave pseudo-potentials method within the LDA approximation in this paper, and the results show that the physical properties are much different from bulk materials. The physical properties of surface In0.25Ga0.75P is observed to be very different from In0.5Ga0.5P and In0.75Ga0.25P and the causes are analyzed in this paper. An indium-gradient surface InxGa1−xP structure has been calculated first time as well, and small differences in electronic and optical properties are found from In0.5Ga0.5P and indium-gradient structures except for x = (0.75, 0.25, 0.5), by which a new way is found to improve the physical properties with a given indium composition.