Mechanism for thermoelectric figure-of-merit enhancement in regimented quantum dot superlattices

We propose a mechanism for enhancement of the thermoelectric figure-of-merit in regimented quantum dot superlattices. A proof-of-concept calculation has been carried out for p-type regimented superlattice of Ge dots on Si. It is shown that when conditions for miniband formations are satisfied, carrier transport in such structures can be tuned in a favorable way leading to large carrier mobility, Seebeck coefficient, and, as a result, to the thermoelectric figure-of-merit enhancement. To maximize the improvement, one has to tune the parameters of quantum dot superlattice in such a way that electrical current is mostly through the well-separated minibands of relatively large width (at least several $k_B\mathrm{T,}$ where $k_B$ is Boltzmann’s constant and T is temperature).