Experimental study of the effect of the quantum well structures on the thermoelectric figure of merit in Si/Si_1-xGe_x system

In bulk form, Si_1-xGe_x is a promising thermoelectric material for high temperature applications. In this paper, we report results from an experimental study as well as theoretical modeling of the quantum confinement effect on the enhancement of the thermoelectric figure of merit. The experimental results provide demonstration of proof of principle for the theoretical model which predicts a large enhancement in the thermoelectric figure of merit for superlattice quantum wells with small widths. Thermoelectric transport properties are measured as a function of temperature. An enhancement of S²n within the quantum well over the bulk value is observed experimentally, where S is the Seebeck coefficient and n is the carrier density.