Thermodynamic and quasi-chemical modeling of point defects in CdTe〈I〉

Charge Carrier Scattering Mechanisms in Thermoelectric PbTe:Sb

“…Specimens of pure and doped lead telluride were prepared by directly alloying previously purified components in evacuated quartz ampoules [5,8]. The obtained material was ground in an agate mortar and, after extracting the fractions with grain sizes of 0.05-0.5 mm, pressed under a pressure of 0.75 GPa.…”

“…The thermoelectric coefficient 𝛼 and the specific conductance 𝜎 were determined following the standard techniques described in work [5] in detail. The specimen to study was placed into an oven between two copper rods, and one of them was heated to create a temperature gradient (of about 10 K/cm) across the specimen.…”

“…Lead telluride (PbTe) is a promising thermoelectric material for medium-temperature (500-700 K) converters of thermal energy [1][2][3]. The basic operational characteristics of PbTe can be improved by modifying its chemical composition, in particular, by doping it with antimony [4][5][6][7][8].…”

“…In work [5] on the basis of quasichemical crystal analysis of doped PbTe:Sb crystals, it was shown that the model of impurity atom redistribution between the metal and chalcogene sublattices can correctly explain the temperature dependence of the charge carrier concentration at the quantitative level, which makes it possible to draw a conclusion about its adequacy. However, the theoretical analysis of the defect subsystem, which was carried out in work [5], does not allow one to determine the influence of technological conditions on the ratio of atomic distributions between the sublattices and to explain why, at the simultaneous filling of cation and anion positions, the donor defects [Sb 1+ Pb ] prevail and the material is characterized by the electron type of conductivity. Moreover, since the growth of the conductivity, which is observed at the doping of lead telluride with antimony [5], can follow from the increase of both charge carrier concentration and mobility, it is expedient to analyze possible models describing the influence of Sb on the properties of PbTe with regard for both those quantities.…”

“…However, the theoretical analysis of the defect subsystem, which was carried out in work [5], does not allow one to determine the influence of technological conditions on the ratio of atomic distributions between the sublattices and to explain why, at the simultaneous filling of cation and anion positions, the donor defects [Sb 1+ Pb ] prevail and the material is characterized by the electron type of conductivity. Moreover, since the growth of the conductivity, which is observed at the doping of lead telluride with antimony [5], can follow from the increase of both charge carrier concentration and mobility, it is expedient to analyze possible models describing the influence of Sb on the properties of PbTe with regard for both those quantities.…”