Anisotropic control of thermal transport in graphene/Si heterostructures

AY Nobakht and S Shin, JOURNAL OF APPLIED PHYSICS, 120, 225111 (2016).

DOI: 10.1063/1.4971873

The cross-plane interaction across interface changes phonon kinetics and spectrum near the interface, and the interaction effects on both in- plane and cross-plane thermal transport are investigated in graphene/Si heterostructure. The interaction with substrates dramatically reduces the in-plane thermal conductivity of graphene by changing the behaviors of the out-of-plane phonons as well as adding phonon-substrate scatterings. Applying pressure up to 2.6 GPa to the sandwiched graphene reduces the cross-plane interfacial thermal resistance by 50% without altering the in-plane thermal conductivity in a significant way. The pressure increases the inter-layer coupling and creates a low-energy phonon transport channel between graphene and Si with minor effects on phonons propagating along the graphene. This study suggests the anisotropic control of thermal transport, and the physics and calculation results can be used to improve the thermal design and analysis in two-dimensional nano-electronic devices. Published by AIP Publishing.

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