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Rapid Characterization of Ultrathin Layers of Chalcogenides on SiO2/Si Substrates

Authors

  • Dattatray J. Late,

    1. Department of Materials Science and Engineering, International Institute of Nanotechnology, Northwestern University, Evanston, IL 60208, USA
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  • Bin Liu,

    1. Department of Materials Science and Engineering, International Institute of Nanotechnology, Northwestern University, Evanston, IL 60208, USA
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  • H. S. S. Ramakrishna Matte,

    1. Chemistry and Physics of Materials Unit, CSIR Centre of Excellence in Chemistry and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced, Scientific Research, Jakkur PO, Bangalore 560064, India
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  • C. N. R. Rao,

    1. Chemistry and Physics of Materials Unit, CSIR Centre of Excellence in Chemistry and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced, Scientific Research, Jakkur PO, Bangalore 560064, India
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  • Vinayak P. Dravid

    Corresponding author
    1. Department of Materials Science and Engineering, International Institute of Nanotechnology, Northwestern University, Evanston, IL 60208, USA
    • Department of Materials Science and Engineering, International Institute of Nanotechnology, Northwestern University, Evanston, IL 60208, USA.
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Abstract

There has been emerging interest in exploring single-sheet 2D layered structures other than graphene to explore potentially interesting properties and phenomena. The preparation, isolation and rapid unambiguous characterization of large size ultrathin layers of MoS2, GaS, and GaSe deposited onto SiO2/Si substrates is reported. Optical color contrast is identified using reflection optical microscopy for layers with various thicknesses. The optical contrast of these thin layers is correlated with atomic force microscopy (AFM) and Raman spectroscopy to determine the exact thickness and to calculate number of the atomic layers present in the thin flakes and sheets. Collectively, optical microscopy, AFM, and Raman spectroscopy combined with Raman imaging data are analyzed to determine the thickness (and thus, the number of unit layers) of the MoS2, GaS, and GaSe ultrathin flakes in a fast, non-destructive, and unambiguous manner. These findings may enable experimental access to and unambiguous determination of layered chalcogenides for scientific exploration and potential technological applications.

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