Interfacial structure optimization is important to enhance the thermal boundary conductance (TBC) as well as the overall performance of thermal conductive composites. In this work, the effect of interfacial roughness on the TBC between copper and diamond is investigated with molecular dynamics (MD) simulations and time-domain thermoreflectance (TDTR) experiments. It is found from MD simulations that the thermal transport efficiency across a rough interface is higher, and the TBC can be improved 5.5 times to 133 MW/m2·K compared with that of the flat interface. Also, the TBC is only dominated by the actual contact area at the interface for larger roughness cases; thus, we conclude that the phonon scattering probability increases with the increase of roughness and becomes stable gradually. Finally, the TBC of the copper/diamond interface with different roughness is characterized by TDTR experiments, and the results also confirm the trend of MD simulations. This study demonstrates the feasibility of the roughness modification for interfacial thermal management from both theoretical analysis and experimental measurements and provides a new idea for enhancing the thermal conductivity of composites.
Keywords: interfacial roughness; molecular dynamics simulation; phonon transmission efficiency; thermal boundary conductance; time-domain thermoreflectance.