ICT2014 Abstracts

Bismuth antimony telluride bulk alloy is one of the strongest candidates for thermoelectric cooling applications. However, its narrow energy gap results in a strong increase in minority carrier conduction above 370 K. In this temperature regime, the thermal activation of electron-hole pair across the energy gap gives rise to a bipolar thermal conductivity, which can be greater than the electronic thermal conductivities of either electrons or holes. Simultaneously, a cancelling of a portion of the Seebeck voltage leads to a drastic reduction in thermoelectric efficiency. Experimentally, it is difficult to isolate the individual contributions of the electron and hole bands. Therefore, we perform a theoretical study on the relationship between minority carriers and the thermoelectric properties such as Seebeck coefficient and bipolar thermal conductivity.