Counting molecular-beam grown graphene layers
Plaut, Annette S.
Garcia, Jorge M.
Pfeiffer, Loren N.
Applied Physics Letters
American Institute of Physics
We have used the ratio of the integrated intensity of graphene's Raman G peak to that of the silicon substrate's first-order optical phonon peak, accurately to determine the number of graphene layers across our molecular-beam (MB) grown graphene films. We find that these results agree well both, with those from our own exfoliated single and few-layer graphene flakes, and with the results of Koh et al. [ACS Nano 5, 269 (2011)]. We hence distinguish regions of single-, bi-, tri-, four-layer, etc., graphene, consecutively, as we scan coarsely across our MB-grown graphene. This is the first, but crucial, step to being able to grow, by such molecular-beam-techniques, a specified number of large-area graphene layers, to order.
Work supported by ONR (N000140610138 and Graphene Muri), EFRC Center for Re-Defining Photovoltaic Efficiency through Molecule Scale Control (award DE-SC0001085), NSF (CHE-0641523), NYSTAR, CSIC-PIF (200950I154), Spanish CAM (Q&C Light (S2009ESP-1503), Numancia 2 (S2009/ENE-1477)), and Spanish MEC (ENE2009-14481-C02-02, TEC2011-29120-C05-04, MAT2011-26534).
Copyright © 2013 American Institute of Physics
Vol. 102 (24), article 241905