The thermo-EMF of an n-type silicon: assessment of the contribution due to the presence of minority carriers

In the common thermoelectric theory, minority charge carriers are assumed to be absent in n- or p-type thermoelectric materials. This study considers their presence and evaluates the effects of that presence on the thermo-electromotive force (Thermo-E.M.F.) of a non-degenerate n-type semiconductor. The calculations are done in the case of silicon. The contribution due to the presence of the minority holes to the total Thermo-E.M.F. depends on the thermopower of minority carriers, their electrical and thermal conductivities. It also depends on their bulk and surface recombinations and depends on the majority carriers only through their thermal and electrical conductivities. In the case of silicon, that contribution remains generally very low although it can increase or decrease the total Thermo-E.M.F. depending on the concentration of the doping elements, the bulk and surface recombination rates, and the length of the sample.