Thermal properties of electrodeposited bismuth telluride nanowires embedded in amorphous alumina

Bismuth telluride nanowires are of interest for thermoelectric applications because of the predicted enhancement in the thermoelectric figure-of-merit in nanowire structures. In this letter, we carried out temperature-dependent thermal diffusivity characterization of a 40nm diameter Bi2Te3 nanowires∕alumina nanocomposite. Measured thermal diffusivity of the composite decreases from 9.2×10−7m2s−1 at 150Kto6.9×10−7m2s−1 at 300K and is lower than thermal diffusivity of unfilled alumina templates. Effective medium calculations indicate that the thermal conductivity along nanowires axis is at least an order of magnitude lower than thermal conductivity of the bulk bismuth telluride.