Enhancement of Seebeck Coefficient in Bi$_{0.5}$Sb$_{1.5}$Te$_{3}$ with High-Density Tellurium Nanoinclusions

Abstract

Bi0.5Sb1.5Te3 films with homogeneously dispersed ∼15 nm Te nanoparticles were prepared by the alternate deposition of Bi0.5Sb1.5Te3 layers and Te nanoparticles. As the amount of Te nanoinclusions increased to 15 vol %, the Seebeck coefficient increased from 169 to 248 µV/K. The authors concluded that the high-density Te nanoinclusions result in a carrier energy filtering effect in Bi0.5Sb1.5Te3. Consequently, the thermoelectric power factor was enhanced by 30% despite a reduction in electrical conductivity. The improvement of the power factor implies the enhancement of the thermoelectric figure of merit ZT, providing the possibility of further ZT improvement by embedding Te nanoinclusions in Bi0.5Sb1.5Te3 bulk materials.