Thermoelectric properties of Bi ₂Te ₃-In ₂Se ₃ composite thin films prepared by Co-sputtering

Bi ₂Te ₃-In ₂Se ₃ films were prepared by co-sputtering followed by annealing, and their structural and thermoelectric properties were investigated. The immiscible nature of the two alloys results in precipitation of the second phase, thus leading to structures with self-assembled dots that are a few nanometers in scale. HAADF-STEM and HRTEM were used to confirm that In ₂Se ₃ nanodots that were a few nanometers in size did indeed form in the Bi ₂Te ₃ thin film. It was found that the incorporation of these nanodots can reduce the thermal conductivity of the thin film.