The effect of texture degree on the anisotropic thermoelectric properties of (Bi,Sb)2(Te,Se)3 based solid solutions

Abstract

Structural anisotropy plays an important role in the thermoelectric properties of the widely used (Bi,Sb)₂(Te,Se)₃ based materials. In this work, (Bi,Sb)₂(Te,Se)₃ based alloys have been fabricated by various methods to produce samples with different orientation factors, F. It is demonstrated that the n-type alloys are much easier to (001) texture than the p-type ones. After hot deformation, the F values decrease by about 20% and 75% for n- and p-type zone-melted samples, and increase by about 60% and 80% for n- and p-type hot-pressed samples, respectively. It is found the in-plane to out-of-plane ratio of thermal and electrical conductivity increases from 1.2–2.2, and 1.1–2.5 respectively, when the F values range from 0.1 to 1, while the Seebeck coefficient is almost isotropic.