Molecular dynamics simulation of thermal boundary conductance between horizontally aligned carbon nanotube and graphene

Abstract

Molecular dynamics simulations are employed to investigate the thermal boundary conductance between a horizontally aligned carbon nanotube (CNT) and graphene. The results show that the thermal boundary conductance increases monotonically with the temperature and the interfacial van der Waals interaction strength. It is also found that the thermal boundary conductance demonstrates strong positive correlation not only with the CNT diameter but also with the system length until it reaches an elevated plateau. After incorporating organic molecules into the interface, the thermal boundary conductance is about one order of magnitude higher than that without organic molecules due to the enhanced matching level of phonon density of states. When tensile strain is applied along the transversal direction, the thermal boundary conductance decreases with increasing stretching strain without organic molecules, and the reduction can be prevented with additional organic molecules. Further analysis indicates that larger overlap between the phonon spectra of organic molecules and sp3 hybridized C atoms can compensate for the softening of high-frequency phonon modes of sp2 hybridized C atoms in graphene induced by tensile strain. This work provides guidance about tuning the thermal transport of C-based nanomaterials for applications in nanoelectronic devices.