Scanning Tunneling Microscopy Study of S Vacancy Defect-Defect Interactions in Monolayer WS<sub>2</sub>

ORAL

Abstract

Atomic defects in crystalline semiconductors strongly affect their electronic properties, such as electron transport and optical response. Defects in two dimensional (2D) semiconductors, such as transition metal dichalcogenides (TMD’s), have a more dramatic impact than bulk counterparts due to less screening and increased substrate interactions. In particular, different atomic vacancies have been reported, but their role in the electronic structure must be established. Deep in-gap states were predicted for different defect structures in 2D TMD’s, but direct experimental observation of defect structure and electronic properties is necessary to tailor TMD’s for device design. Here we report the creation of a high concentration of S vacancy defects in WS2 monolayers by vacuum annealing, and characterization of their electronic properties and structure using scanning tunneling microscopy and spectroscopy. We find that interaction of nearby S vacancies results in a rich variety of deep in-gap states, shedding light on the role of defects in TMD electronic properties.

*This work was supported by NSF MRSEC (DMR-1720595) and DMR-EPM (DMR-1808751) as well as contributions from the US Airforce (FA2386-18-1-4097) and the Welch Foundation (F-1672).

–

Presenters

  • Madisen Holbrook

    • Physics, University of Texas at Austin

Authors

  • Madisen Holbrook

    • Physics, University of Texas at Austin

  • Chao Lei

    • Physics, University of Texas at Austin

  • Wei-Ting Hsu

    • Physics, National Tsing Hua University

  • Li-Syuan Lu

    • Department of Electrophysics, National Chiao Tung University
    • Electrophysics, National Chiao Tung University

  • Wen-Hao Chang

    • Department of Electrophysics, National Chiao Tung University
    • Electrophysics, National Chiao Tung University
    • Natl Chiao Tung Univ

  • Allan MacDonald

    • Physics, University of Texas at Austin
    • Physics Department, University of Texas at Austin
    • University of Texas at Austin
    • Department of physics, University of Texas at Austin
    • Department of Physics, University of Texas at Austin
    • University of Texas, Austin

  • Feliciano Giustino

    • Physics, University of Texas at Austin
    • University of Texas at Austin
    • Oden Institute for Computational Engineering and Sciences, University of Texas at Austin
    • Department of Physic, The University of Texas at Austin, Austin, Texas 78712, USA, Oden Institute for Computational Engineering and Sciences
    • Oden Institute, University of Texas at Austin
    • Department of Materials, University of Oxford
    • Department of Physics, University of Texas at Austin
    • ODEN Institute for Computational Engineering and Sciences, University of Texas at Austin

  • Philipp Ebert

    • Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons

  • Chih-Kang Shih

    • Physics, University of Texas at Austin
    • University of Texas at Austin
    • Department of Physics, The University of Texas at Austin