Enhancement of thermoelectric properties of sputtered Bi-Sb-Te thin films by electric current stressing

Abstract

Both electrical conductivity and Seebeck coefficient of sputtered Bi-Sb-Te films were enhanced by introducing a high density of electric current through the films during thermal annealing. The electrically stressed Bi-Sb-Te films were found to have lower carrier concentration but much higher mobility than the films thermally treated at the same temperatures. A mechanism based on electromigration-induced preferential Sb diffusion is proposed to explain the observed electrical transport properties and precipitation of Sb-rich phase in the electrically stressed Bi-Sb-Te films. The study shall lead to an effective strategy of improving thermoelectric properties of Bi-Sb-Te films by electric current stressing. © 2008 American Institute of Physics.