Transport and photoluminescent characterization of high-quality single layer WSe<sub>2</sub> devices

ORAL

Abstract

Single layer semiconducting transition metal dichalcogenides (TMD) are direct band gap
semiconductors that exhibit a variety of novel phenomena, ranging from valley hall effect to
highly correlated electron physic. However, the transport studies of many of these phenomena
have been hindered by low mobility, defective TMD materials. While the defect density of
commercially grown TMD can be higher than 0.1%, in this work we use flux grown TMD
samples with defect density significantly reduced to 0.01%. We report unprecedently high hole
mobility values of up to 30,000 cm2/V.s in single layer (1L) WSe2 encapsulated in between hBN
single crystals. Unlike that of conventional semiconductors, mobility of flux grown WSe2
devices increases with reduced carrier density, indicating that mobility is not dominated by
charged impurities. We find the quantum scattering time, tauq, to be ~400 ps, similar to tauq
in graphene devices. Moreover, by preforming photoluminescence spectroscopy, we find
extremely sharp exciton linewidth (>1meV) and other optical features such as dark excitons and
biexcitons.

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Presenters

  • Kateryna Pistunova

    • Physics, Harvard University
    • Harvard University

Authors

  • Kateryna Pistunova

    • Physics, Harvard University
    • Harvard University

  • Luis Jauregui

    • Physics, Harvard University
    • Harvard University

  • Andrew Y Joe

    • Physics, Harvard University
    • Harvard University

  • Kristiaan De Greve

    • Harvard University
    • Physics, Harvard University

  • Andrey Sushko

    • Physics, Harvard University
    • Harvard University

  • Daniel A Rhodes

    • Columbia University
    • Physics, Columbia University
    • National High Magnetic Field Laboratory, Tallahassee, FL-32310, USA.
    • Columbia Nano Initiative, Columbia University
    • Department of Mechanical Engineering, Columbia University, New York, NY 10027 USA
    • Mechanical Engineering, Columbia University
    • Columbia Univ

  • James Hone

    • Columbia University
    • Mechanics, Columbia University
    • Department of Mechanical Engineering, Columbia University in the City of New York
    • Department of Mechanical Engineering, Columbia University
    • Department of Mechanical Engineering, Columbia University, New York, NY 10027 USA
    • Mechanical Engineering, Columbia University

  • Hongkun Park

    • Dept. of Chemistry and Chemical Biology and Dept. of Physics, Harvard University
    • Harvard University
    • Chemistry and Chemical Biology, Harvard University

  • Mikhail Lukin

    • Harvard University
    • Physics, Harvard University

  • Philip Kim

    • Harvard University
    • Department of Physics, Harvard University & School of Engineering and Applied Sciences, Harvard University
    • Department of Physics, Harvard University, Cambridge, MA 02138, USA.
    • Physics, Harvard University
    • Physics and Applied Physics, Harvard University
    • Physics department, Harvard University