Preparation and thermoelectric properties of ZnTe-doped Bi0.5Sb1.5Te3 single crystal

In this work, Bi0.5Sb1.5Te3 single crystal doped with 6 mol% ZnTe was fabricated using a vertical Bridgman method. A region about 20 x 70 mm(2) in dimensions along (001) cleavage plane is obtained. The as-grown crystal exhibits remarkable anisotropy of TE properties that parallel and perpendicular to (001) in 300-480 K temperature range. It is found the highest power factor PF parallel to(0 01) = similar to 50 mu Wcm(-1)K(-2) and PF perpendicular to(0 0 1) = similar to 18 mu Wcm(-1)K(-2) are obtained, and the total thermal conductivities for both directions are kappa(parallel to(0 0 1)) = 1.8 Wm(-1)K(-1) and kappa(perpendicular to(0 0 1)) = 0.8 Wm(-1)K(-1). Thus, the peak figure of merit ZT(parallel to(0 0 1)) = 1.05 and ZT(perpendicular to(0 0 1)) = 0.9 are realized, which might expand its application scope compared with the commercial Bi2Te3-based TE materials. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this work, a Bi0.5Sb1.5Te3 single crystal doped with 6 mol% ZnTe was successfully fabricated using a vertical Bridgman method. The crystal exhibits remarkable anisotropy of TE properties parallel and perpendicular to the (001) cleavage plane, showing potential for expanded applications compared to commercial Bi2Te3-based TE materials.