Thermal conductivity of isotopically modified graphene

• Published in: Nature materials 2012-01, Vol.11 (3), p.203-207
• Main Authors: Chen, Shanshan, Wu, Qingzhi, Mishra, Columbia, Kang, Junyong, Zhang, Hengji, Cho, Kyeongjae, Cai, Weiwei, Balandin, Alexander A., Ruoff, Rodney S.
• Format: Article
• Language: English
• Subjects: 639/301/357/918; 639/301/357/995; Biomaterials; Chemical vapor deposition; Chemistry and Materials Science; Condensed Matter Physics; Conductivity; Crystals; Electronics; Experimental data; Gases; Graphene; Graphite - chemistry; Heat transfer; Isotopes; letter; Materials Science; Mathematical models; Molecular Dynamics Simulation; Nanostructures - chemistry; Nanotechnology; Optical and Electronic Materials; Physics; Surface Properties; Temperature; Thermal Conductivity; Thermal energy; Thermal properties; Three dimensional; Two dimensional
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat3207

Among other exotic properties graphene exhibits the highest thermal conductivity observed so far. This is true at least for graphene composed of only 12 C atoms. However, it is now shown experimentally that regions of 13 C atoms can substantially reduce the thermal conductivity. Aside from their fundamental importance, these results suggest that thermal conductivity can be tailored by varying the relative amounts of carbon isotopes used. In addition to its exotic electronic properties 1 , 2 graphene exhibits unusually high intrinsic thermal conductivity 3 , 4 , 5 , 6 . The physics of phonons—the main heat carriers in graphene—has been shown to be substantially different in two-dimensional (2D) crystals, such as graphene, from in three-dimensional (3D) graphite 7 , 8 , 9 , 10 . Here, we report our experimental study of the isotope effects on the thermal properties of graphene. Isotopically modified graphene containing various percentages of 13 C were synthesized by chemical vapour deposition (CVD). The regions of different isotopic compositions were parts of the same graphene sheet to ensure uniformity in material parameters. The thermal conductivity, K , of isotopically pure 12 C (0.01%  13 C) graphene determined by the optothermal Raman technique 3 , 4 , 5 , 6 , 7 , 10 , was higher than 4,000 W mK −1 at the measured temperature T m ~320 K, and more than a factor of two higher than the value of K in graphene sheets composed of a 50:50 mixture of 12 C and 13 C. The experimental data agree well with our molecular dynamics (MD) simulations, corrected for the long-wavelength phonon contributions by means of the Klemens model. The experimental results are expected to stimulate further studies aimed at a better understanding of thermal phenomena in 2D crystals.