Near field study of twisted transition metal dichalcogenide bilayers

ORAL

Abstract

Twistronics has recently emerged as a novel tuning knob to engineer the properties of electrons and excitons in two dimensional van der Waals heterostructures. However, directly probing the properties of vdW heterostructures within a single moiré unit cell remains elusive. In this talk, we utilize near-field optical microscopy to explore twisted transition metal dichalcogenides (TMD) bilayers. The atomically thin vertical p-n junction of WSe2/MoSe2 bilayer is fabricated by mechanical exfoliation and stacking. The type-II band alignment of the WSe2/MoSe2 facilitates electron-hole separation permitting photocurrent measurements at the nanoscale. Features with ~100 nm periodicity are observed and show systematic evolution under electro-static gating. More experiments are carrying out to conclusively assign these features to the moiré. Our study demonstrates a viable pathway towards probing and manipulating moiré patterned TMD heterostructures at the nanoscale.

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Presenters

  • Shuai Zhang

    • Columbia Univ
    • Columbia University
    • Department of Physics, Columbia University

Authors

  • Shuai Zhang

    • Columbia Univ
    • Columbia University
    • Department of Physics, Columbia University

  • Aaron Sternbach

    • Columbia Univ
    • Department of Physics, Columbia University
    • Physics, Columbia University

  • Baichang Li

    • Department of Mechanical Engineering, Columbia University

  • Lin Zhou

    • Nanjing University
    • Department of Chemistry, Columbia University

  • Wenjing Wu

    • Columbia University
    • Department of Chemistry, Columbia University

  • Lin Xiong

    • Columbia Univ
    • Columbia University
    • Department of Physics, Columbia University
    • Physics, Columbia University

  • Essance Ray

    • University of Washington
    • Department of Physics, University of Washington

  • Nathan P Wilson

    • Department of Physics, University of Washington
    • University of Washington

  • Xiaodong Xu

    • Department of Physics, University of Washington

  • Xiaoyang Zhu

    • Columbia Univ
    • Chemistry, Columbia University
    • Columbia University, Chemistry
    • Columbia University
    • Department of Chemistry, Columbia University

  • James C Hone

    • Columbia University
    • Mechanical Engineering, Columbia University
    • Columbia Univ
    • Physics, Columbia University
    • Columbia University, NY, USA
    • Department of Mechanical Engineering, Columbia University

  • Dmitri Basov

    • Columbia University, The Department of Physics
    • Columbia University
    • Physics, Columbia University
    • Columbia Univ
    • Department of Physics, Columbia University