Heat dissipation at a graphene-substrate interface
ZP Xu and MJ Buehler, JOURNAL OF PHYSICS-CONDENSED MATTER, 24, 475305 (2012).
The development of nanoelectronics faces severe challenges from Joule heating, leading to high power density and spatial localization of heat, which nucleates thermal hot spots, limits the maximum current density and potentially causes catastrophic materials failure. Weak interfacial coupling with the substrate is a major route for effective heat mitigation in low-dimensional materials such as graphene and carbon nanotubes. Here we investigate the molecular-scale physics of this process by performing molecular dynamics simulations, and find that significant heating in graphene supported by a silicon carbide substrate cannot be avoided when the areal power density exceeds P-G = 0.5 GW m(-2). A steady state will be established within 200 ps with a significant temperature difference built up across the interface, and the interfacial thermal conductivity kappa(c) increases at higher power densities from 10 to 50 MW m(-2) K-1. These observations are explained by a two-resistor model, where strong phonon scattering at the interface may perturb the ballistic heat transport and lead to a diffusive mechanism. Nanoengineering the interfacial thermal coupling by intercalating guest atoms shows potential for designing thermally transparent but electronically insulating interfaces, which paves the way for simultaneously optimizing thermal management and charge carrier mobility in nanoelectronics.
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