Firstprinciple investigation of the surface states of tin dioxide (100).

As an important functional film, tin dioxide (SnO 2) was widely used in the communities of gas sensors as well as solar cells. SnO 2 (110) and (100) surfaces were thought to be stable, and both could be easily obtained by common preparation method. The characteristics of SnO 2 surface were critical to the performance of devices when it was applied in solar cells, and the SnO 2 (100) surface had not been understood explicitly. A series of SnO 2 (100) surface models with different terminal atoms were built in this work and calculated by density functional theory (DFT) with GGA + U. SnO 2 (100) surfaces with different terminal atoms exhibited distinctly different surface states. Basically, these surface states mainly originated from the terminal atoms, and they extended to the tenth monoatomic layer. SnO 2 (100) surface terminated with single monolayer of O atoms was the structure with the least surface states. The real surface of SnO 2 was thought to be consisting of O terminal atoms mostly. The charge neutral level of SnO 2 (100) surface was thought to be 2.94 eV above the valence band. Image 1 • SnO 2 (100) with different terminal atoms was investigated systematically by first-principle calculations. • Surface states were origin from the ten monolayers of surface and showed different characters with different terminal atoms. • The real surface of SnO 2 (100) was mainly terminated with O, and surface states mainly from structure terminated with Sn. [ABSTRACT FROM AUTHOR]