Enhancing thermal transport across diamond/graphene heterostructure interface

YL Liu and L Qiu and JL Liu and YH Feng, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 209, 124123 (2023).

DOI: 10.1016/j.ijheatmasstransfer.2023.124123

The thermal properties of two-dimensional materials and their heterostructure are critical for efficient heat dissipation in nano- devices. A good example is graphene which exhibits excellent in-plane ther-mal transport properties. However, the substantial interfacial thermal resistance between graphene and the substrate greatly hinders its practical application. Diamond is a good choice as a substrate to reduce out-of-plane phonon scattering when graphene is contacted with the substrate because of their high structural similarity. Based on non- equilibrium molecular dynamics simulations, the effects of graphene layer count and the temperature on the thermal conductance of diamond/graphene heterostructure are investigated. The results show that the interfacial thermal conductance of diamond/single-layer graphene heterostructure is at least double that of diamond/multi-layer graphene heterostructure. Moreover, high temperature is also conducive to thermal transport for diamond/graphene heterostructure. Due to the anisotropy of graphene, the in-plane and out-of-plane phonon density of state were analyzed. The trend of overlap energy of out-of-plane phonon density of state is consistent with that of the interfacial thermal conductance, which suggests that out-of-plane phonon has a greater effect on heat transport at the inter-face. The increasing temperature excites more high-frequency phonons, and thus, promotes the phonon coupling of diamond and graphene. This well explains the increases in interfacial thermal conductance at a higher temperature.(c) 2023 Elsevier Ltd. All rights reserved.

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