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arXiv · 1603.05286

Thermal Conductivity of Suspended Graphene with Defects

Hoda Malekpour·Pankaj Ramnani·Srilok Srinivasan·Ganesh Balasubramanian·Denis L. Nika·Ashok Mulchandani·Roger Lake·Alexander A. Balandin
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Abstract

We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. Graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5-micrometer size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0x10^10 cm-2 to 1.8x10^11 cm-2 the thermal conductivity decreases from ~(1.8+/-0.2)x10^3 W/mK to ~(4.0+/-0.2)x10^2 W/mK near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation behavior at a relatively high value of ~400 W/mK. The thermal conductivity dependence on defect density is analyzed using the Boltzmann transport equation and molecular dynamics simulations. The results are important for understanding phonon - point defect scattering in two-dimensional systems and for practical applications of graphene in thermal management.

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Hoda Malekpour, Pankaj Ramnani, Srilok Srinivasan, Ganesh Balasubramanian, Denis L. Nika, Ashok Mulchandani, Roger Lake, Alexander A. Balandin. 2016-03-16. Thermal Conductivity of Suspended Graphene with Defects. https://doi.org/10.1039/c6nr03470e

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