Enhanced Thermoelectric Properties of p-Type Bi0.5Sb1.5Te3 Thin Films by Post-Annealing Process

Abstract

Recent studies have focused on significantly enhancing the figure-of-merit ( ZT) of nanostructured materials by size reduction and interface control. In this regard, bismuth-telluride-based semiconductor materials are excellent materials for fabricating high-performance thermoelectric ( TE) devices that are operative below 400 K. There are very limited reports on the thermal conductivity of bismuth-telluride-based compound thin films. Thus, information regarding the TE properties, including the thermal conductivity, of the films is required to assess these nanostructured materials. In this study, we analyzed the influence of post-annealing on the TE properties of nanostructured p-type Bi0.5Sb2Te3 ( p-BST) thin films with a thickness of 100 nm. The electrical and thermoelectric properties, including the thermal conductivity, of the films were investigated by subjecting the samples to annealing treatment at temperatures of 20-250 degrees C under Ar atmosphere. Increasing the annealing temperature to 200 degrees C led to substantial improvement of the electrical and thermoelectric properties of the p-BST films, whereby the electrical resistivity of conductivity was similar to 212 Scm(-1) and the thermal conductivity was similar to 0.24 W/mK for the p-BST thin film annealed at 200 degrees C.