400 element ErAs:InGaAs/InGaAlAs superlattice power generator

Abstract

ABSTRACTWe report the fabrication and characterization of thin film power generators composed 400 p- and n-type ErAs:InGaAs/InGaAlAs superlattice thermoelectric elements. The thermoelectric elements incorporate erbium arsenide metallic nanoparticles into the semiconductor superlattice structure to provide charge carriers and create scattering centers for phonons. 10 µm p- and n-type InGaAs/InGaAlAs superlattices with embedded ErAs nano-particles were grown on InP substrates using molecular beam epitaxy. Thermal conductivity values were measured using the 3ω method and cross-plane Seebeck coefficients were determined using Seebeck device test patterns. 400 element ErAs:InGaAs/InGaAlAs thin film power generators were fabricated from superlattice elements 10 µm thick and 200 µm × 200 µm in area. The output power was 4.7 milliwatts for an external electrical load resistor of 150 Ω at about 80 K temperature difference drop across the generator. We discuss the limitations to the generator's performance and provide suggestions for further improvement.