Charge states of tin impurity atoms and their effect on the electric conductivity of In2S3

The aim of the paper is to determine variation possibility for indium charge state in In2S3 crystals at deviation from stoichiometry by chalcogen and at tin alloyage and to determine effect of this impurity on electrical features of the considered compound, as well. Charge states of tin and indium atoms in pure and alloyed In2S3 are determined by means of photoelectron and Moessbauer spectroscopy. Effect of tin on electrical properties of In2S3:Sn monocrystals depending on its concentration and level of deviation from stoichiometry by sulphur is determined by electric conductivity measurement. The authors explain the observed variations of electric conductivity and charge state of tin ions by vacancy formation in anion sublattice. It is supposed, that long-term annealing promotes localization of sulphur negatively charged vacancies near Sn+4 ions with recharging of the latters into Sn2+ which explains certain stabilization ion of electric conductivity of indium sulfide at tin alloyage