Cross-plane thermal transport in multiplayer graphene/h-BN van der Waals heterostructures: The role of interface morphology

Abstract

The combination of dissimilar materials to build heterostructures has opened up new possibilities for the use of graphene in a variety of applications. Among these, the stacking of graphene and h-BN into graphene/h-BN (GBN) van der Waals (vdW) heterostructures is particularly promising for use as thermal interface materials and underfill materials in new electronic devices because of their remarkable thermal properties and electrical insulation endowed by h-BN if it encapsulates graphene. The heat dissipation performance of these GBN heterostructures depends heavily on the interfacial thermal conductance (ITC) of graphene and h-BN. Herein we explore the heat transfer across multilayer GBN vdW heterostructures by nonequilibrium molecular dynamics simulations and put emphasis on the interface morphology. The tunable ITC of the heterostructure can be achieved by modifying the interfacial layers through composition diffusion, vacancy density and pattern, hydrogenation, and isotope. The simulation results demonstrate that hydrogenation is the most efficient approach to tailor the ITC with a large variation, followed by the composition diffusion. Composition diffusion can induce a stronger interaction between graphene and h-BN, resulting in a 70% improvement in the ITC of the GBN vdW heterostructure. This study offers valuable perspectives to the physical mechanisms behind the interface morphology-dependent ITC, and can facilitate the design of novel GBN vdW heterostructures for efficient heat dissipation.