Thermal interface materials (TIMs) play a central role in the performance and reliability of electronic systems. They are the route for thermal conduction between semiconductor chips and metal heat spreaders, heat pipes, and heat sinks, and must withstand thermomechanical stresses due to thermal cycling. Particularly challenging TIM applications include thermoelectric power generators and high-power radar systems.

We are exploring the use of nanostructured materials based for application as thermal interface materials. Early work focused on disordered mixtures of carbon nanotubes and nanoparticles, and more recent results have focused on aligned films of single and multi-wall carbon nanotubes. Metrology is a key part of this project because the distribution of thermal resistance between the internal film volume and its interfaces with metallization layers and the substrate are determined independently. We have also developed measurements of the in-plane elastic modulus of these films based on a micromechanical resonator approach, and have pioneered measurements of the thermal conductivities of individual carbon nanotubes using internal electrical heating. Ongoing work is focused on implementation in thermoelectric generators for waste heat recovery in vehicles, as well as detailed investigations of the physics governing thermal and mechanical properties.