Sponsors: IFC/MARCO, ONR, NSF, DOE
Carbon nanotubes offer unusual thermal, mechanical, and electrical properties, which vary with chirality, geometry (multiwall vs single-wall), and length. They are promising for a variety of applications in electronic systems and MEMS including as passive regions for aggressive heat conduction, as well as for active regions in transistors and as interconnects. The coupling of electrical and thermal transport in carbon nanotubes is a particularly compelling area for fundamental research owing to the unusual band structures for these energy carriers.
We developed measurements of the thermal, electrical, and coupled electrothermal properties of individual carbon nanotubes and carbon nanotube arrays. These data provided the first compelling evidence of severe phonon nonequilibrium in nanotubes subjected to high electrical current densities, and also provided insight into the thermal conductance between carbon nanotubes and substrates. We have also studied the impact of carbon nanotube inclusions in fluidic mixtures, e.g., nanofluids, for applications in convection cooling. These measurements suggested that CNTs can assist with heat conduction through the thermal boundary layer in developing flow and increase the effective heat convection coefficient. More recent data have investigated the potential of aligned CNT films for application as interface and other packaging materials.