Compact Model for Thermoelectric Power Factor Enhancement by Energy Barriers in a Two-phase Composite Semiconductor

We have modeled the thermoelectric power factor enhancement by energy barriers in a one-dimensional composite semiconductor using the Boltzmann transport equation within the relaxation time approximation. The effective transport coefficients of the composite structure are calculated assuming two-phases connected in series: (i) the grain and (ii) the barrier. For the grains, bulk properties are assumed. For the barriers, the transport coefficients are calculated within Boltzmann transport equationand assuming thermionic emission over an energy barrier. The power factor enhancement is calculated as function of the relevant parameters of the material. It is found that power factor enhancement is possible in the presence of energy barriers. The role of the non-uniformity in the thermal conductivity is considered. Moreover, the occurrence of simultaneous increase of the conductivity and Seebeck with carrier density and its effect on the power factor enhancement is discussed.