Thermoelectric effects of quantum dot arrays embedded in nanowires

TL;DR

This paper theoretically investigates the thermoelectric properties of quantum dot arrays in nanowires, demonstrating the potential for high thermoelectric efficiency at room temperature by optimizing electron and phonon thermal conductances.

Contribution

It introduces a combined theoretical approach to analyze thermoelectric effects in quantum dot arrays embedded in nanowires, highlighting the potential for high ZT values.

Findings

Electron thermal conductance is much smaller than phonon conductance in the Coulomb blockade regime.

Optimal ZT can be achieved by increasing thermal power and reducing phonon conductance.

ZT values larger than one are possible at room temperature for InGaAs/GaAs quantum dot arrays.

Abstract

The thermoelectric properties of quantum dot arrays (QDAs) embedded in nanowires connected to electrodes are studied theoretically in the Coulomb blockade regime. A Hurbbard-Anderson model is used to simulate the electronic contribution to thermoelectric proper- ties of a QDA junction system. The electrical conductance, Seebeck coefficient, and electron thermal conductance are calculated by both the Keldysh Green function method and the mean-field approach. The phonon thermal conductivities are calculated by using the equation of phonon radiative transfer method. In the Coulomb blockade regime the electron thermal conductance is much smaller than the phonon thermal conductance. Therefore, the optimal figure of merit (ZT) can be enhanced by increasing thermal power and decreasing phonon thermal conductance simultaneously. We found that it is possible to obtain ZT value of InGaAs/GaAs QDAs embedded in nanowires larger than one at room temperature.