2599 © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com small 2011, 7, No. 18, 2599–2606 Centimeter-Scale High-Resolution Metrology of Entire CVD-Grown Graphene Sheets Jennifer Reiber Kyle, Ali Guvenc, Wei Wang, Maziar Ghazinejad, Jian Lin, Shirui Guo, Cengiz S. Ozkan,* and Mihrimah Ozkan* 1. Introduction Graphene is a two-dimensional sheet of graphite con- sisting of one to ten layers of carbon atoms arranged in hex- agonal lattices. Only six years after first fabricating graphene in the laboratory, Geim and Novoselov were awarded the Nobel Prize in physics for their work on graphene. [1] This relatively short time between discovery and recognition is due in part to the fact that graphene was extensively studied theoretically long before it was discovered experimentally. The greatest obstacle to experimental discovery of graphene was the difficulty in detecting the graphene sheets. A single- layer graphene sheet is only ≈0.4 nm thick [2] and absorbs only 2.3% of incident light. [3] This difficulty was overcome in 2004, when the first graphene sheets were created by mechanical exfoliation of highly ordered graphite and visualized by DOI: 10.1002/smll.201100263 J. R. Kyle, A. Guvenc, Prof. M. Ozkan Department of Electrical Engineering University of California Riverside , CA 92521, USA E-mail: mihri@ee.ucr.edu W. Wang, M. Ghazinejad, J. Lin, Prof. C. S. Ozkan Department of Mechanical Engineering and the Materials Science and Engineering Program University of California Riverside, CA 92521, USA E-mail: cengiz.ozkan@ucr.edu S. Guo Department of Chemistry University of California Riverside, CA 92521, USA A high-throughput metrology method for measuring the thickness and uniformity of entire large-area chemical vapor deposition-grown graphene sheets on arbitrary substrates is demonstrated. This method utilizes the quenching of fluorescence by graphene via resonant energy transfer to increase the visibility of graphene on a glass substrate. Fluorescence quenching is visualized by spin-coating a solution of polymer mixed with fluorescent dye onto the graphene then viewing the sample under a fluorescence microscope. A large-area fluorescence montage image of the dyed graphene sample is collected and processed to identify the graphene and indicate the graphene layer thickness throughout the entire graphene sample. Using this metrology method, the effect of different transfer techniques on the quality of the graphene sheet is studied. It is shown that small-area characterization is insufficient to truly evaluate the effect of the transfer technique on the graphene sample. The results indicate that introducing a drop of acetone or liquid poly(methyl methacrylate) (PMMA) on top of the transfer PMMA layer before soaking the graphene sample in acetone improves the quality of the graphene dramatically over immediately soaking the graphene in acetone. This work introduces a new method for graphene quantification that can quickly and easily identify graphene layers in a large area on arbitrary substrates. This metrology technique is well suited for many industrial applications due to its repeatability and flexibility. Graphene