Infrared probe of charge dynamics in graphene transistors

ORAL

Abstract

We report on infrared (IR) spectroscopy of charge dynamics in monolayer graphene. IR reflectance and transmission measurements were performed on graphene transistors as a function of gate voltage. From these data, we obtained the optical conductivity of graphene at various carrier densities. The dominant feature of the optical conductivity is an interband transition with the onset at twice the Fermi energy, which evolves systematically with gate voltage. Similar behavior was observed with the Fermi level on either side of the Dirac point. We will compare these results with theoretical predictions and discuss several new aspects of the charge dynamics in graphene uncovered by this work.

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Authors

  • Zhiqiang Li

    University of California, San Diego, Univ. of California, San Diego

  • Erik Henriksen

    Columbia University

  • Zhigang Jiang

    Columbia University/NHMFL, NHMFL

  • Zhao Hao

    Lawrence Berkeley National Laboratory, Advanced Light Source, Lawrence Berkeley National Laboratory

  • Michael Martin

    Lawrence Berkeley National Laboratory, Advanced Light Source, Lawrence Berkeley National Laboratory

  • Philip Kim

    Physics Department, Columbia University, Columbia University

  • Horst Stormer

    Columbia University/Bell Labs, Columbia University

  • Dimitri Basov

    Univ. of California, San Diego, University of California San Diego, Department of Physics, University of California, San Diego, University of California, San Diego, University of California at San Diego