The effect of self-assembled monolayers on graphene conductivity and morphology

ORAL

Abstract

Graphene transport properties are limited by charge defects in SiO$_{2}$, and by large charge density due to strong interaction with SiC. To modify these effects we have treated 300 nm SiO$_{2}$ with tricholosilanes with different termination groups including pure and fluoro and amino-terminated hydrocarbons for use as substrates for mechanical exfoliation of graphene. XPS measurements verify the presence of the expected termination groups. AFM measurements reveal modified monolayer roughness and correlation lengths; for a fluorinated carbon chain the RMS roughness is 0.266 $\pm $ 0.017 nm and the correlation length is 10.2 $\pm $ 0.7 nm compared to 0.187 $\pm $ 0.011 nm and 19.8 $\pm $ 2.5 nm for SiO$_{2}$. Surface free energies of the monolayers and the SiO$_{2}$ blank have been computed from static contact angle measurements and all decrease the SiO$_{2 }$surface free energy; for the fluorinated carbon chain monolayer a decrease of 20 mJ/m$^{2}$ from SiO$_{2}$. We will discuss the ease of exfoliation, and the morphology and conductivity of graphene on these monolayers.

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Authors

  • T. L. Moore

    • University of Maryland, College Park

  • Jian-Hao Chen

    • University of Maryland, College Park
    • Department of Physics and University of Maryland Materials Research Science and Engineering Center, University of Maryland, College Park, MD 20742
    • Dept of Physics, Center for Nanophysics and Advanced Materials, and Materials Research Science and Engineering Center, Univ. of Maryland, College Park
    • University of Maryland
    • Department of Physics, University of Maryland
    • Materials Research Science and Engineering Center, Center for Nanophysics and Advanced Materials, Dept of Physics, Univ. of Maryland, College Park, MD

  • Blake Riddick

    • University of Maryland, College Park
    • Physics Department, University of Maryland, College Park, MD 20742

  • Ellen Williams

    • University of Maryland, College Park
    • Department of Physics and University of Maryland Materials Research Science and Engineering Center, University of Maryland, College Park, MD 20742
    • University of Maryland
    • LPS, CNAM, and the DOP, UM
    • Physics Department, University of Maryland, College Park, MD 20742
    • Materials Research Science and Engineering Center, Center for Nanophysics and Advanced Materials, Dept of Physics, Univ. of Maryland, College Park, MD
    • University of Maryland College Park
    • Dept. of Physics, U. of Maryland - College Park
    • Department of Physics and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD 20742-4111, USA