Two-Dimensional Phonon Transport in Supported Graphene

Abstract

The reported thermal conductivity (kappa) of suspended graphene, 3000 to 5000 watts per meter per kelvin, exceeds that of diamond and graphite. Thus, graphene can be useful in solving heat dissipation problems such as those in nanoelectronics. However, contact with a substrate could affect the thermal transport properties of graphene. Here, we show experimentally that kappa of monolayer graphene exfoliated on a silicon dioxide support is still as high as about 600 watts per meter per kelvin near room temperature, exceeding those of metals such as copper. It is lower than that of suspended graphene because of phonons leaking across the graphene-support interface and strong interface-scattering of flexural modes, which make a large contribution to kappa in suspended graphene according to a theoretical calculation.

Structure of graphene and its disorders: a review

“…However, the thermal conductivity of graphene significantly decreases when it is in contact with a substrate such as SiO 2 [267] or confined in GNRs [268], due to the high-sensitivity of the phonon propagation in an atomically thin graphene sheet to surface or edge perturbations [269]. Numerical simulations [270] indicate that the scattering of phonons by defects and delocalized interaction between them lead to a transition of thermal transfer process from propagating mode to diffusive modes.…”

Temperature-Dependent Mean Free Path Spectra of Thermal Phonons Along the c-Axis of Graphite

“…The best known of these materials, graphite, possesses ultrahigh in-plane thermal conductivity of ∼ 2000 W/mK [13] and cross-plane (c-axis) thermal conductivity around 6.8 W/mK [14] at room temperature, yielding an anisotropy factor of around 300. During the past decade, research has mainly focused on thermal transport properties along the in-plane direction, especially in graphene, the ideal two-dimensional system isolated from the ab-plane [15][16][17][18][19][20][21][22]. Such a high in-plane thermal conductivity has important applications in heat dissipation [5,23].…”

Understanding Divergent Thermal Conductivity in Single Polythiophene Chains Using Green–Kubo Modal Analysis and Sonification

“…In electrically conductive materials, electrons can become the primary heat carriers, but in all phases of matter, atomic motions are always present and contribute to the thermal conductivity of every object. Here, we use the term "object" instead of "material" to emphasize that thermal conductivity is highly dependent on the actual structure of an object, that is, its internal atomic level structure and its larger nanoscale or microscale geometry [1][2][3][4][5][6] . In studying the physics of thermal conductivity, tremendous progress has been made over the last 20 years toward understanding various mechanisms that allow one to reduce thermal conductivity in solids 1,7 .…”