The effect of electrolyte impurities on the thermoelectric properties of electrodeposited Bi2Te3 films

Abstract

An increase of up to 2.5 times in the power factor can be obtained just by using different high purity Te reagents from different suppliers. The obtained results demonstrate that the incorporation of trace impurities from the Bi2Te3 electrochemical bath play an important role in the thermoelectric properties of the film. To make that observation, bismuth telluride (Bi2Te3) films were electrodeposited under the same conditions, but using three different Te powder sources. All the powders tested have a nominal purity equal to or higher than 99.99%. In all the cases, we could achieve films with highly oriented along the [110] direction, with the same 2 to 3 Bi/Te ratio, and similar surface, and cross-sectional morphology. However, the thermoelectric properties (electrical conductivity, Seebeck coefficient, and thermal conductivity) depended strongly on the used tellurium powders sources used. Inductively coupled plasma mass spectrometry measurements were performed to determine which elements influence the final thermoelectric properties of Bi2Te3 films.