www.london-nano.com Rayleigh imaging and Raman spectroscopy of graphene Cinzia Casiraghi Fachbereich Physik, Freie Universität Berlin Graphene is the two-dimensional building block for the carbon allotropes of every other dimensionality: graphite, nanotubes and buckyballs can all be viewed as derivatives of graphene. Graphene has unique properties: it is the thinnest and strongest material in the universe and it shows giant charge carriers mobility [1]. Its charge carriers have the smallest effective mass (it is zero) and they can travel micrometer-long distances without scattering at room temperature [1]. Graphene also shows very high thermal conductivity and stiffness and it is the only membrane impermeable to gases [2]. Electron transport in graphene is described by a Dirac-like equation, which allows the investigation of relativistic quantum phenomena [3]. Because of its mechanical stability, ballistic transport and compatibility with planar technology, graphene is a promising candidate for future electronic applications [4]. However, the identification and counting of graphene layers is still a major hurdle as monolayers are a great minority amongst accompanying thicker flakes [1]. Thus, developing tools for the quick, non-destructive identification of graphene layers is imperative to enable graphene technology. In this talk I will show that Rayleigh and Raman spectroscopy are fast, sensitive and not-destructive techniques able to identify graphene. Rayleigh spectroscopy is a very efficient tool for mapping substrates in search of graphene and to count the number of layers [5]. Raman Spectroscopy is able to uniquely distinguish graphene from few-layers graphene and graphite, and also to monitor the amount of disorder and doping, edges and charged impurities in graphene [6-11]. This makes Raman spectroscopy a powerful tool for the investigation of graphene, which can be easily used to monitor the changes in the graphene properties from synthesis to device fabrication. 1. A. K. Geim and K. S. Novoselov, Nature Materials, 6, 183 (2007) 2. A. K. Geim, arXiv:0906.3799 3. A. H. Castro Neto et al. Review of Mod. Phys. 81, 109 (2009) 4. M.Y. Han et al, Phys. Rev. Lett. 98, 206805 (2007) 5. C. Casiraghi et al., Nano Lett. 7, 2711 (2007) 6. A. C. Ferrari, et al., Phys. Rev. Lett. , 97, 187401 (2006) 7. S. Pisana et al., Nature Mat. 6, 198 (2007) 8. C. Casiraghi et al., Appl. Phys. Lett. 91, 233108 (2007) 9. C. Casiraghi, RRL-Phys Status Solidi 3, 175 (2009) 10. C. Casiraghi et al., Nano Lett. 9, 1433 (2009) 11. C. Casiraghi, arXiv:0908.4480 .