Toward enhanced thermoelectric effects in Bi2Te3/Sb2Te3 heterostructures

The possibility of enhanced thermoelectric properties through nanostructuring is investigated theoretically in a p-type Bi2Te3/Sb2Te3 heterostructure. A multi-scale modeling approach is adopted to account for the atomistic characteristics of the interface as well as the carrier/phonon transport properties in the larger scales. The calculations clearly illustrate the desired impact of carrier energy filtering at the potential barrier by locally boosting the power factor over a sizable distance in the well region. Further, the phonon transport analysis illustrates a considerable reduction in the thermal conductivity at the heterointerface. Both effects are expected to provide an effective means to engineer higher zT in this material system.