THERMAL-CONDUCTIVITY REDUCTION IN SIGE ALLOYS BY THE ADDITION OF NANOPHASE PARTICLES

Transport models have predicted that the thermal conductivity of SiGe alloys could be appreciably reduced by incorporating discrete 40 Angstrom particles within the SiGe grains. These particles would scatter the thermal phonons which transport most of the heal in these alloys. Such a thermal conductivity reduction would lead to substantial improvements in the figure-of-merit and efficiency of thermoelectric materials used in power generation applications. This paper reports on the results of adding 40 Angstrom particles to SiGe by using a spark erosion process. Thermal conductivity reductions consistent with the transport models have been achieved; however, the improvement in figure-of-merit has not been as large as predicted.