Thermal conductivity and heat transfer in superlattices

Abstract

Understanding the thermal conductivity and heat transfer processes in superlattice structures is critical for the development of thermoelectric materials and optoelectronic devices based on quantum structures. This letter reports modeling of the heat transfer and thermal conductivity of superlattice structures based on solving the Boltzmann transport equation. Both diffuse and specular phonon scattering processes at interfaces are considered. The modeling results could explain recent experimental data on the cross-plane thermal conductivity of Si/Ge superlattices. Below the critical thickness, thermal conductivity is strongly influenced by diffuse interface scattering of phonons while above the critical thickness, dislocations are the dominant scattering centers in superlattices.