ErAs: InGaAs/InGaAlAs superlattice thin-film power generator array

We report a wafer scale approach for the fabrication of thin-film power generators composed of arrays of 400 p and n type ErAs:InGaAs/InGaAlAs superlattice thermoelectric elements. The elements incorporate ErAs metallic nanoparticles into the semiconductor superlattice structure to provide charge carriers and create scattering centers for phonons. p- and n-type ErAs:InGaAs/InGaAlAs superlattices with a total thickness of 5 μm were grown on InP substrate using molecular beam epitaxy. The cross-plane Seebeck coefficients and cross-plane thermal conductivity of the superlattice were measured using test pattern devices and the 3ω method, respectively. Four hundred element power generators were fabricated from these 5 μm thick, 200 μm × 200 μm in area superlattice elements. The output power was over 0.7 mW for an external resistor of 100 Ω with a 30 K temperature difference drop across the generator. We discuss the limitations to the generator performance and provide suggestions for improvements.