Density functional theory study of the electronic and optical properties of Si incorporated SnO2

The effect of Si concentration on the electronic and optical properties of Si incorporated SnO2 was investigated by density functional theory. SnO2 maintained the direct bandgap after Si incorporation, and the value of bandgap enlarged as the Si concentration increased. The formation of the Si–O covalent bond could reduce electron losses of Sn atoms that resulted in the decrease of electron concentration of SnO2 through the density of states and charge density analysis. On the basis of the calculation results of the optical properties including the dielectric function, refractive index, reflectivity, absorption, and electron energy-loss spectrum, the values of these parameters were reduced at a low energy region and these curves gradually shifted toward high energy as the Si concentration increased. It suggested that the optical properties of SnO2 could be improved by the Si atom over the infrared and visible spectra.