Dimensional crossover of thermal transport in few-layer graphene

Abstract

Graphene, in addition to its unique electronic and optical properties, reveals unusually high thermal conductivity. The fact that the thermal conductivity of large enough graphene sheets should be higher than that of basal planes of bulk graphite was predicted theoretically by Klemens. However, the exact mechanisms behind the drastic alteration of a material's intrinsic ability to conduct heat as its dimensionality changes from two to three dimensions remain elusive. The recent availability of high-quality few-layer graphene (FLG) materials allowed us to study dimensional crossover experimentally. Here we show that the room-temperature thermal conductivity changes from approximately 2,800 to approximately 1,300 W m(-1) K(-1) as the number of atomic planes in FLG increases from 2 to 4. We explained the observed evolution from two dimensions to bulk by the cross-plane coupling of the low-energy phonons and changes in the phonon Umklapp scattering. The obtained results shed light on heat conduction in low-dimensional materials and may open up FLG applications in thermal management of nanoelectronics.

Generalized Two-Temperature Model for Coupled Phonons in Nanosized Graphene

“…Recent studies 9,23,[48][49][50] showed that the thermal conductivity of graphene increases logarithmically (~logL) with the size of sample, which is taken to fit MD results shown in Fig. 3.…”

Structure of graphene and its disorders: a review

“…These properties include excellent room temperature electrical conductivity with mobility of up to 40,000 cm 2  V −1  s −1 [123], high room temperature thermal conductivity of about 2800 W m −1  K −1 [124,125], outstanding mechanical stiffness and strength with a Young’s modulus of about 0.8 TPa [126,127], fine transparency with white light transmittance of about 95% [128], and impermeability to gases [129]. Zhang and Gu [130] carried out molecular dynamics (MD) simulations on multi-layer graphene with layer number varying from one to seven, and found that the mechanical properties (i.e.…”

“…Infrared (IR) absorption/reflection spectroscopy can be used to characterize the stacking order in graphene [124], but this technique has a low spatial resolution [150]. In contrast, the stacking structures in tri- and tetralayer graphenes are readily visualized by Raman imaging, owing to the clear associations with the distinctive line shapes and widths in the Raman 2D mode [174] (see Figure 10(e,f)).…”

Human‐Like Sensing and Reflexes of Graphene‐Based Films

“…d) Thermal conductivity as a function of the layer number of graphene. Reproduced with permission 14. Copyright 2010, Nature Publishing Group.…”

“…Similar with the transparency of graphene, its thermal conductivity also decreased with the increase of the layer numbers. The thermal conductivity in room temperature changes from ≈2800 to ≈1300 W mK –1 as the layer number of graphene increasing from 2 to 4, caused by the interlayer coupling of the low‐energy phonons (Figure 1d) 14. On the other hand, graphene has a lower convective heat‐transfer coefficient than CNTs and metals (e.g., chromium), benefitting from its ideal flat surface which would determine higher final temperature and a faster heating rate 15…”