pubs.acs.org/cm r XXXX American Chemical Society Chem. Mater. XXXX, XXX, 000–000 A DOI:10.1021/cm101027c Novel Liquid Precursor-Based Facile Synthesis of Large-Area Continuous, Single, and Few-Layer Graphene Films Anchal Srivastava,* ,†,‡ Charudatta Galande, † Lijie Ci, † Li Song, † Chaitra Rai, § Deep Jariwala, †,^ Kevin F. Kelly, § and Pulickel M. Ajayan* ,† † Department of Mechanical Engineering and Materials Science, and § Department of Electrical and Computer Engineering and the Rice Quantum Institute, Rice University, Houston, Texas 77005, and ‡ Department of Physics, Banaras Hindu University, Varanasi, 221005, India. ^ Present Address: Department of Metallurgical Engineering, Institute of Technology, Banaras Hindu University, Varanasi 221005, U.P, India Received February 24, 2010 Graphene has attracted a great deal of attention because of its unique band structure and electronic properties that make it promising for applications in next-generation electronic devices, transparent flexible conducting electrodes, and sensors. Here, we report the substrate selective growth of centimeter size (∼3.5 cm  1.5 cm), uniform, and continuous single and few-layer graphene films employing chemical vapor deposition technique on polycrystalline Cu foils using liquid precursor hexane. Structural characterizations suggest that as-grown graphene films are mostly single and few layers over large areas. We have demonstrated that these graphene films can be easily transferred to any desired substrate without damage. A liquid-precursor-based synthesis route opens up a new window for simple and inexpensive growth of pristine as well as doped graphene films using various organic liquids containing the dopant atoms. Introduction Graphene is a monolayer of sp 2 -bonded carbon atoms packed into a honeycomb crystal structure and can be viewed either as an individual atomic plane extracted from graphite or unrolled single-wall carbon nanotubes. 2D graphene crystals exhibit many exciting properties, like room temperature quantum Hall effect, 1 long-range ballistic transport at room temperature with around ten times higher electron mobility than silicon, 2 availability of charge carriers that behave as massless relativistic quasiparticles like Dirac fermions, 3 quantum confine- ment resulting in finite band gap and Coulomb blockade effects in graphene nanoribbons, 4 and ultimate sensitivity of adsorption of individual gas molecules. 5 This two- dimensional material, despite its short history, has al- ready established an area of exciting research for new physics and potential applications in electronics. To realize the above properties and applications of graphene, a consistent, reliable, simple and inexpensive method of growing high-quality, uniform, and continuous, single, and few-layer graphene films is a prerequisite. Graphene flakes produced by exfoliating graphite are limited by its size and scalability. 6 Epitaxial growth of multilayer gra- phene on SiC single crystal at atmospheric pressure requires high temperatures of around 1650 °C. 7 Recently, graphene growth by a vapor phase deposition of gaseous hydrocarbons on metal substrates such as Ni, Co, Ir, Ru, etc., has been reported. 8-11 Large-scale synthesis of gra- phene flakes using supported metal catalysts has also been achieved using RF-cCVD. 12 However, the problem of efficiently synthesizing high-quality, single-layer grap- hene still persists. More recently, large-area, single-layer graphene has been grown on Cu substrates by chemical vapor deposition technique using methane gas as a precursor. 13 This method produces large-area, mostly single-layer graphene; however, the major disadvantage *To whom correspondence should be addressed. E-mail: ajayan@rice.edu (P.M.A.); anchalbhu@gmail.com (A.S.). (1) Novoselov, K. S.; Jiang, Z.; Zhang, Y.; Morozov, S. V.; Stormer, H. L.; Zeitler, U.; Maan, J. C.; Boebinger, G. S.; Kim, P.; Geim, A. K. Science 2007, 1137201. (2) Berger, C.; Song, Z.; Li, X.; Wu, X.; Brown, N.; Naud, C.; Mayou, D.; Li, T.; Hass, J.; Marchenkov, A. N.; Conrad, E. H.; First, P. N.; de Heer, W. A. Science 2006, 1125925. (3) Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Katsnelson, M. I.; Grigorieva, I. V.; Dubonos, S. V.; Firsov, A. A. Nature 2005, 438, 197. (4) Ozyilmaz, B.; Jarillo-Herrero, P.; Efetov, D.; Kim, P. Appl. Phys. Lett. 2007, 91, 192107. (5) Schedin, F.; Geim, A. K.; Morozov, S. V.; Hill, E. W.; Blake, P.; Katsnelson, M. I.; Novoselov, K. S. Nat. Mater. 2007, 6, 652. (6) Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. A. Science 2004, 306, 666. (7) Emtsev, K. V.; Bostwick, A.; Horn, K.; Jobst, J.; Kellogg, G. L.; Ley, L.; McChesney, J. L.; Ohta, T.; Reshanov, S. A.; Rohrl, J.; Rotenberg, E.; Schmid, A. K.; Waldmann, D.; Weber, H. B.; Seyller, T. Nat. Mater. 2009, 8, 203. (8) Fan, S.; Liu, L.; Liu, M. Nanotechnology 2003, 14, 1118. (9) Ferrari, A. C.; Meyer, J. C.; Scardaci, V.; Casiraghi, C.; Lazzeri, M.; Mauri, F.; Piscanec, S.; Jiang, D.; Novoselov, K. S.; Roth, S.; Geim, A. K. Phys. Rev. Lett. 2006, 97, 187401. (10) Gilje, S.; Han, S.; Wang, M.; Wang, K. L.; Kaner, R. B. Nano Lett. 2007, 7, 3394. (11) Isett, L. C.; Blakely, J. M. Surf. Sci. 1976, 58, 397. (12) Dervishi, E.; Li, Z.; Watanabe, F.; Biswas, A.; Xu, Y.; Biris, A. R.; Saini, V.; Biris, A. S. Chem. Commun. 2009, 4061.