Gate Dependent Transition Metal Dichalcogenide Photoluminescence and Absorption Spectroscopy

ORAL

Abstract

Transition metal dichalcogenides (TMDs) are a class of semiconductors which can be easily exfoliated (i.e. cleaved) into atomically thin layers. At the monolayer limit, TMDs become direct-gap semiconductors and possess exciton resonances with large binding energies, on the order of hundreds of millielectronvolts. We fabricate van der Waals heterostructures in which monolayer TMDs are encapsulated between two hexagonal boron nitride flakes. We gate these passivated monolayers by adding an additional graphene monolayer using a dry transfer method. We study the photoluminescence and absorption of these high-quality samples at cryogenic temperatures (T=4K) as a function of the Fermi level, which we modulate via an applied gate voltage. We measure the linewidth of the neutral exciton to be less than 1nm, and find that our samples are spectrally homogeneous (variations within a linewidth) over several micrometers.

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Presenters

  • Ryan Gelly

    Physics, Harvard University

Authors

  • Ryan Gelly

    Physics, Harvard University

  • Giovanni Scuri

    Harvard Univ, Physics, Harvard University, Harvard University

  • You Zhou

    Harvard Univ, Physics, Harvard University, Physics, Chemistry and Chemical Biology, Harvard University, Harvard University

  • Kristiaan De Greve

    Harvard Univ, Physics, Harvard University, Harvard University

  • Alexander High

    Institute for Molecular Engineering, University of Chicago, Physics, Harvard University, Harvard University, The Institute for Molecular Engineering, University of Chicago

  • Luis Jauregui

    Department of Physics, Harvard University, Harvard Univ, Physics, Harvard University, Harvard University

  • Kateryna Pistunova

    Department of Physics, Harvard University, Physics, Harvard University, Harvard Univ, Harvard University

  • Andrew Joe

    Physics, Harvard University, Harvard University

  • Dominik Wild

    Harvard Univ, Physics, Harvard University, Harvard University

  • Mikhail Lukin

    Harvard University, Physics, Harvard Univ, Harvard Univ, Department of Physics, Harvard University, Physics, Harvard University

  • Philip Kim

    Physics, Harvard University, Harvard University, Department of Physics, Harvard University, Harvard Univ, Physics, Harvard, Department of Physics, Harvard university, School of Applied Sciences and Engineering, Harvard University

  • Hongkun Park

    Harvard Univ, Physics, Harvard University, Physics, Chemistry and Chemical Biology, Harvard University, Harvard University, Chemistry and Physics, Harvard University