| Using the generalized gradient approximation method based on the first-principles of density functional theory and the ultrasoft pseudopotential method, the doping parameters of La and S co-doped SnO2 were calculated, and their stability, elastic properties and electrical conductivity of the doped structure were analyzed. The results showed that the formation energy of doping systems increased with S atom doping concentration, and that the stability decreased with increase of doping S atom. Compared with individual either La or S doping, the hardness of the co-doped structure was reduced, while its toughness was increased, and its toughness gradually decreased with the increase of S atom concentration. La and S co-doping still belonged to P-type doping, and new impurity levels were introduced in the forbidden band, so the band gap was narrowed, leading to the enhancement of the conductivity of the co-doped system. The hybridization of S-3p orbital with Sn-5s and La-5d orbital was enhanced with the increase of S doping concentration. and the conductivity was further improved with the increase of impurity levels introduced in the forbidden bands. |
