Effect of annealing on thermoelectric properties of crystals YbxBi2−xTe3

Abstract

The work is devoted to the study of the thermoelectric properties of solid crystal YbxBi[Formula: see text]Te3. This work presents the results of studies of the thermoelectric properties of YbxBi[Formula: see text]Te3 ([Formula: see text]) solid solutions before and after annealing in the temperature range 300–580[Formula: see text]K. Regularities of changes in the electrical conductivity, Seebeck coefficient, and total thermal conductivity of the samples depending on the content of ytterbium (Yb) are established. Dependences of electrical conductivity, Seebeck coefficient, and the thermal conductivity on temperature for the crystal under study are plotted. Temperature curves were recorded using a Termoscan-2 low-frequency temperature recorder at a heating rate of 283[Formula: see text]K/min. Studies of conductivity [Formula: see text], thermoelectric power (S) were carried out by the four-probe method at direct current in the temperature range of 300–600[Formula: see text]K. Ohmic contacts were applied using alloys. It has been established that the optimal combination of these thermoelectric characteristics is achieved for the compositions [Formula: see text], which are characterized by the maximum thermoelectric index ([Formula: see text]) of the figure of merit in the temperature range of 420–500[Formula: see text]K after annealing at 500[Formula: see text]K for [Formula: see text][Formula: see text]h. It was revealed that the YbxBi[Formula: see text]Te3 systems under study are n-type semiconductor thermoelectric materials in the temperature range of 300–600[Formula: see text]K.