Electric Charge and Heat Transfer in SnTe Single Crystal with Various Vacancy Concentration in Tin Sublattice
- PDF / 219,878 Bytes
- 5 Pages / 595 x 794 pts Page_size
- 86 Downloads / 229 Views
ELECTRIC CHARGE AND HEAT TRANSFER IN SnTe SINGLE CRYSTAL WITH VARIOUS VACANCY CONCENTRATION IN TIN SUBLATTICE N. M. Akhundova1 and G. D. Abdinova2
UDC 621.315.592
The paper explores the electrical conductivity, thermoelectric coefficient and thermal conductivity of SnTe crystals with the hyperstoichiometric tin content up to 1.0 at.% in the 90–300 K temperature range. Identified are the electron and lattice components of thermal conductivity and thermal resistance created by the structural vacancies. It is shown that the temperature dependencies of the electrical conductivity and thermoelectric coefficient are explained well by the model of two valence bands, whereas that of thermal conductivity are determined by the phonon-phonon scattering. Extrinsic stacking faults in the amount of 0.05 at.% Sn, create donor centers in the SnTe crystal, thereby decreasing its electrical and thermal conductivities. When the concentration of the extrinsic stacking faults is higher than 0.05 at.% Sn, they occupy the vacancies and enhance these parameters. Keywords: crystal, vacancies, extrinsic stacking fault, thermal conductivity, additional thermal resistance.
INTRODUCTION Tin telluride (SnTe) is a p-type semiconductor with a complex valence band, it crystallizes with a deviation from stoichiometry and its specimens contain electrically active vacancies in the sublattice with the tin concentration up to 1020–1021 cm–3 [1–6]. This leads to various characteristics of this compound, the transport properties of which are not fully clarified. This limits the application of tin telluride and its solid solutions, which are rather promising for electronics engineering. Structural vacancies as scattering centers for electrons and phonons also manifest themselves during the heat transfer in SnTe crystals. In this respect, the synthesis of SnTe crystals with different vacancy concentration in the tin sublattice and a study of their electrical and thermal properties are of great scientific and practical importance. On this basis it is considered that the vacancy concentration in the tin sublattice of SnTe crystals can be reduced via the introduction of hyperstoichiometric extrinsic Sn stacking faults in the crystal. This would provide the SnTe crystal growing with various vacancy concentrations and the investigation of structural vacancies during the electric charge and heat transfer. With a request for information about mechanisms of the electric charge and heat transfer and the role of defects created by vacancies in the tin sublattice, this paper focuses on the synthesis of SnTe single crystals with the hyperstoichiometric tin content of about 1.0 at.% and studies their electrical conductivity, thermoelectric coefficient and thermal conductivity in the temperature range from 90 to 300 K.
1
Azerbaijan State University of Economics, Baku, Azerbaijan, е-mail: [email protected]; 2Institute of Physics Azerbaijan National Academy of Sciences, Baku, Azerbaijan, е-mail: [email protected]. Translated from Izvestiya Vysshikh Uch
Data Loading...
