Thermal conductivity of epitaxial graphene nanoribbons on SiC: effect of substrate

TL;DR

This study investigates how SiC substrates influence the thermal conductivity of epitaxial graphene nanoribbons, revealing substrate interactions significantly reduce thermal transport, while bilayer GNRs preserve intrinsic properties due to weak interlayer forces.

Contribution

It provides new insights into substrate effects on GNR thermal conductivity and highlights the role of out-of-plane phonon modes in multilayer structures.

Findings

Substrate interaction reduces thermal conductivity of single-layer GNRs.

Bilayer GNRs maintain thermal properties of suspended GNRs.

Out-of-plane phonons critically affect thermal transport in multilayer GNRs.

Abstract

We study the effect of SiC substrate on thermal conductivity of epitaxial graphene nanoribbons (GNRs) using the nonequilibrium molecular dynamics method. We show that the substrate has strong interaction with single-layer GNRs during the thermal transport, which largely reduces the thermal conductivity. The thermal conductivity characteristics of suspended GNRs are well preserved in the second GNR layers of bilayer GNR, which has a weak van der Waals interaction with the underlying structures. The out-of-plane phonon mode is found to play a critical role on the thermal conductivity variation of the second GNR layer induced by the underlying structures.