A departure of the solid solution from the stoichiometric cross-section Bi2Te3-Sb2Te3 for a relationship Bi:Sb=1:2 and 2:1

Polythermal cross sections of the triple system Bi-Sb-Te passing from the tellurium angle into the regions of the compositions Bi2Te3x2Sb2Te3 and 2Bi2Te3xSb2Te3 were constructed. The microstructure analysis was carried out after annealing at temperatures of 450, 400, 350, and 250 deg C for 200 hr. The variation of the electrophysical properties in relation to the composition was studied. The experimental data showed that a solid solution based on Bi2Te3-Sb2Te3 deviates from the stoichiometric cross section on Bi2Te3-Sb2Te3 and lies between 59.4 and 59.95 at.% Te. As the content of Bi2Te3 in the alloys increases, the homogeneity region approaches the stoichiometric cross section of Bi2Te3-Sb2Te3, intersecting it near the composition Bi2Te3x2Sb2Te3. A drastic change in properties is observed in the homogeneity regions, the concentration of the current carriers reducing and the thermal e.m.f. increasing