Interfacial thermal resistance of 2D and 1D carbon/hexagonal boron nitride van der Waals heterostructures

The newly emerging graphene/hexagonal boron nitride (h-BN) van der Waals heterostructures has attracted much research interest due to its new properties and functions for practical applications in nanodevices. In this work, molecular dynamics simulations are performed to study the interfacial thermal resistance (ITR) of a graphene/h-BN bilayer system as well as its one-dimensional counterpart, a concentric CNT/BNNT double-walled nanotube, based on the lumped capacity model. The calculated ITR is in an order of magnitude of 10−7-10−6 Km2/W and it monotonically decreases with temperature and interlayer/intertube coupling strength. It is believed that the ITR between graphene and h-BN is reduced through the enhancement of the coupling strength instead of the geometrical overlap of the phonon modes. Heat flux direction has no effect on the ITR of the graphene/h-BN bilayer, however, radial thermal rectification is found in the CNT/BNNT composite, with a largest thermal rectification factor of ∼90%. Thermal energy always prefers to transport from the outer nanotube towards the inner nanotube in the CNT/BNNT system over the opposite direction no matter the outer nanotube is CNT or BNNT because the outer nanotube has more high-frequency phonons than that of the inner nanotube in the CNT/BNNT system.