$ErAs:InGaAs∕InGaAlAs$ 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 $5μm$ 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 $5μm$ thick, $200μm×200μm$ in area superlattice elements. The output power was over $0.7mW$ for an external resistor of $100Ω$ with a $30K$ temperature difference drop across the generator. We discuss the limitations to the generator performance and provide suggestions for improvements.