Annealing behavior of Bi2Te3 thermoelectric semiconductor electrodeposited for nanowire applications

Abstract

Bi2Te3 films were electrodeposited for nanowire applications and the effects of annealing in a H-2 atmosphere and an Ar ambient on the thermoelectric properties of the electrodeposited Bi2Te3 films were investigated. The Bi2Te3 films electrodeposited in solutions with Bi/(Bi+Te) mole ratios of 50% and 60% exhibited the strong (110) preferred orientation. The behaviors of the thermoelectric properties were almost identical for the annealing treatments in a H-2 atmosphere and in an Ar ambient. The power factor of the Bi2Te3 film without a (110) preferred orientation, as electrodeposited in a solution with a Bi content of 40%, was remarkably improved from 3.1 X 10(-4) W/K-2-m to 16.5 similar to 18.6 x 10(-4) W/K-2-m by annealing in a H-2 atmosphere and in an Ar ambient. However, no improvement of the power factor could be achieved by annealing the Bi2Te3 films with (110) preferred orientations. The interaction between the electrodeposited Bi2Te3 film and the Ti seed layer also affected the annealing behavior of the electrodeposited Bi2Te3 film.