X-Ray Photoemission Spectroscopy Studies of Sn-Doped Indium-Oxide Films.

摘要

The In and Sn 3d(3/2) and 3d(5/2) ESCA peaks and the oxygen 1s peak of Sn-doped In2O3 films were compared with those for In2O3 films and In2O3, SnO, SnO2, and Sn3O4 powders. Comparison of as-grown with sanded surfaces revealed Sn-rich surface layers in those films having good optical and transport properties. These experimental findings are interpreted with a schematic energy-band model and the assumption that film darkening in Sn-doped In2O3 films is caused by the formation and growth of an Sn3O4-like second phase in the bulk. Suppression of this phase could be accomplished by higher substrate temperatures, which permit equilibrium conditions to be attained: Sn-rich phases appear to migrate to the film surface, and the tin disproportionates to Sn(2+) and Sn(4+) ions. (Author)