High figure of merit thermoelectrics

The thermoelectric figure of merit of a semiconductor, ZT = α2σT/λ, can be calculated from a small number of microscopic material parameters, the material composition, doping level and the temperature. The functional dependence of ZT on these parameters has been studied for a range of material parameters using a recently developed model which accurately and self-consistently describes the thermoelectric properties of n-type silicon-geranium alloys. ZT values several times larger than current state of the art values of ZT ∼ 1 are shown to be entirely consistent with existing theory, even using material parameters already observed. A vigorous search for materials with much higher figure of merit values therefore remains of interest, in spite of several decades of relatively slow progress in this area