Electrostatic Screening of Charged Defects in 2D Materials

ORAL

Abstract

Two dimensional (2D) semiconductors, such as transition metal dichalcogenides (TMDCs) monolayers, are an emerging class of materials that show promise in the development of highly efficient nanoscopic optoelectronic devices. A major factor hampering TMDC monolayers device performance is the inconsistent quality of TMDCs due to presence of defects/traps. Here we show that charged defects can be electrostatically screened/passivated. We find that contacting TMDC monolayers with an ionic liquid reduces charge carrier trapping and non-radiative recombination. This effect is reversible and can increase photoluminescence yield by as much as two-orders of magnitude while suppressing the photoluminescence emission from trions. We propose that the mobile ions electrostatically screen local charged vacancies within the TMDC monolayer, thus protecting excitons from scattering with the defect sites.

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Authors

  • Timothy Atallah

    Department of Chemistry, Columbia University

  • Melissa Bosch

    Department of Physics and Astronomy, University of Minnesota, Twin Cities

  • Jue Wang

    Department of Chemistry, Columbia University, Columbia University

  • Dongjea Seo

    Department of Mechanical Engineering, Columbia University, Columbia Univ

  • Osman Moneer

    Department of Chemistry, Columbia University

  • Justin Zhu

    Department of Chemistry, Columbia University

  • Demi Ajayi

    Department of Mechanical Engineering, Columbia University

  • Jenny Ardelean

    Department of Mechanical Engineering, Columbia University

  • Haiming Zhu

    Department of Chemistry, Columbia University, Columbia University

  • Monica Theibault

    Department of Chemistry, University of California, Berkeley

  • James Hone

    Columbia University, Columbia Univ, Department of Mechanical Engineering, Columbia University

  • Xiaoyang Zhu

    Department of Chemistry, Columbia University, Columbia University