<title>Electronic properties and energy spectrum of SnTe doped with In</title>

Abstract

ABSTRACT The temperature and concentration dependences of electrical conductivity o Hall coefficient RH and coefficient of thermo-e.m.f. S for the samples ofthe SnTe solid solutions are obtained. On the basis of experimental data the model of energyspectrum of SnTe doped with In taking into account the high concentration of nonstoichiometric vacancies in SnTe andvariable valency of the In atoms is proposed. According to the model the valence band contains two resonance bandscorresponding to the In atoms localized in octa- and tetrahedral positions (In and In3 respectively). The vacancy band is the lowest on the energy scale of the valence band, followed by impurity bands. The gaps and their temperature dependences, carrier mobilities in the different impurity bands are obtained. The doping mechanism of In introduced indifferent proportions with vacancies is determined by impurity band state occupation in consecutive order according to theirlocation on the energy scale and by the Fermi level position. The Fermi level is located in one of the impurity bandsdepending on proportion ofIn1 and In3 atoms and vacancies.Keywords: SnTe solid solutions, Hall coefficient, electrical conductivity, coefficient of thermo-e.m.f., temperaturedependences, concentration dependences, energy spectrum, vacancy band, impurity band.