Thermoelectric and mechanical properties of (Bi₁₋ₓSbₓ )₂Te₃(x = 0÷0.07) semiconductor solid solutions

Abstract

The dependences of thermoelectric properties and microhardness on the composition of polycrystalline (Bi₁₋ₓSbₓ )₂Te₃ solid solutions in the concentration range x = 0÷0.07 at room temperature were investigated. A drastic growth of microhardness was discovered with a simultaneous reduction of the Hall coefficient, the Seebeck coefficient and electric conductivity with increase in antimony content x = 0.005 – 0.01, following which with further increase in x to x = 0.01 – 0.015, the type of the dependences was reversed. The observed effect is attributable to a high degree of crystal lattice disorder with the introduction of the first portions of impurity and to subsequent relaxation processes with formation of percolation channels in crystal impurity subsystem. With further increase in x, the Hall coefficient and the Seebeck coefficient practically do not change with composition, and the observed more complicated dependence of microhardness and electric conductivity on x is interpreted as a manifestation of short-range processes in a solid solution.