Mössbauer Studies of Reactively Deposited Tin Oxide Films

Abstract

Valence state of tin ions in the reactively deposited SnO_x films were analyzed by Mössbauer spectroscopy. Both the amorphous and crystallized films were composed of Sn²⁺ and Sn⁴⁺. With increasing oxygen pressure, the oxidized degree of the amorphous films was increased to be saturated at the film composition of SnO_1.5, while it was decreased at the higher substrate temperatures. The crystallized films was markedly oxidized at the higher substrate temperatures. The film composition was nearly SnO₂ at 420°C. The values of the isomer shift and quadrupole splitting of Sn²⁺ and Sn⁴⁺ in the amorphous films suggested the oxygen coordinations for Sn²⁺ and Sn⁴ similar to those in Sn₂O₂ crystals, nearly independent of the film composition.