Thermal Conductance of Solid-Solid Interfaces

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Interfaces play a critical role in controlling heat transport in nanostructures and nanostructured materials because surfaces and interfaces limit the mean-free-path of phonons and low values of the interface thermal conductance inhibit the transfer of energy between dissimilar materials. Materials with high densities of internal interfaces-e.g., short period superlattices and multilayers, and nanocrystalline materials-show promise of providing low thermal conductivity materials for thermoelectrics and thermal barrier coatings. The goal of the proposed work is to establish a greater understanding of the thermal conductance of interfaces by elucidating the mechanisms that limit heat transport between similar materials and the mechanisms that produce anomalously large transport between dissimilar materials. The research team will study epitaxial films of TiN/MgO; Ag on H-terminated and clean Si; Au and Pt films on H-terminated diamond; and nanolaminates of W/Al2O3 synthesized by atomic-layer-deposition. These experiments will exploit the team's recent advances in thermal property measurement using time-domain thermoreflectance. The experimental methods being developed in this work are also enabling improved metrology tools for characterizing heat-transfer in microscale devices.