Single-Crystal Growth of Bi-Sb-Te Thermoelectric Materials by Halide Chemical Vapor Transport Technique

Abstract

This report describes synthesis of binary Bi2Te3 and ternary Bi0.5Sb1.5Te3 single crystals using the halide chemical vapor transport technique. For synthesis of ternary Bi0.5Sb1.5Te3, BiBr3 is a more effective transport agent compared with iodine I2. The single crystal includes a few atomic percent of Br. The Bi0.5Sb1.5Te3 crystal shows p-type conduction and has a comparatively large residual resistivity ratio. The crystal exhibits relatively high electrical resistivity and high Seebeck coefficient. These high values are attributed to decrease of the hole concentration p due to doping of the transport agent Br.