Photo-electric properties of preferred orientation of tin oxide studied by first-principles

Tin oxide (SnO2) is a material owning competitive properties of optical transparency and electrical conductivity. Different preferred orientation films have been prepared by experiments. However, it is not clear that the effect of preferred orientation on photo-electric properties. In this work, structure and photo-electric properties of four preferred orientations were calculated by first-principles. The results showed that surface energy of (1 1 0) and (2 0 0) surfaces was lower than that of (2 1 1) and (3 0 1) surfaces. Furthermore, (2 0 0) surface had charge densities of valence band maximum (VBM) and conduction band minimum (CBM) distributed in the whole system and suitable VBM and CBM positions, which could enhance carrier concentration and conductivity. (2 1 1) and (3 0 1) surfaces are easy to achieve p-type doping, but (1 1 0) and (2 0 0) surfaces are opposite. Meanwhile, (2 0 0) and (3 0 1) preferred orientations have low optical absorption in visible spectrum. Our results provide a useful guidance for preparation of high performance SnO2 films.