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Preferential hole defect formation in monolayer WSe<sub>2</sub> by electron-beam irradiation

ORAL

Abstract

Monolayer transition-metal dichalcogenides (TMDs) have been studied extensively. Scanning transmission electron microscopy (STEM) has been used to both image and generate chalcogen vacancies, which then agglomerate into different multivacancy structures or linear defects. Density-functional-theory (DFT) calculations have been used to describe the formation of select such defects in several TMDs. Here we demonstrate that, in WSe2, an initial formation of particular multivacancy structures gradually leads to a high density of 10-, 12-, 14-, and 16-member-ring round holes. In contrast, in WS2, chalcogen vacancies agglomerate only into line defects. Time-lapse images and DFT calculations are used to track the agglomeration of chalcogen vacancies and identify the atomic-scale processes that energetically favor hole formation in WSe2 and linear structures in WS2. The demonstrated control of high-density round holes in WSe2 has potential for novel applications such as atomic and molecular sieving.

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Presenters

  • Donghan Shin

    Department of Physics and Astronomy, Vanderbilt Univ, Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA, Department of Physics and Astronomy, Vanderbilt University

Authors

  • Donghan Shin

    Department of Physics and Astronomy, Vanderbilt Univ, Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA, Department of Physics and Astronomy, Vanderbilt University

  • Gang Wang

    Department of Physics, Southern University of Science and Technology

  • Andrew O'Hara

    Department of Physics and Astronomy, Vanderbilt Univ, Department of Physics and Astronomy, Vanderbilt University, Vanderbilt Univ

  • Mengjiao Han

    Department of Physics, Southern University of Science and Technology, Southern University of Science and Technology, SOUTHERN UNIVERSITY OF SCIENCE AND TECHNOLOGY, CHINA

  • Junhao Lin

    Department of Physics, Southern University of Science and Technology, Southern University of Science and Technology, SOUTHERN UNIVERSITY OF SCIENCE AND TECHNOLOGY, CHINA

  • Sokrates T Pantelides

    Department of Physics and Engineering, Vanderbilt University, Department of Physics and Astronomy, Vanderbilt Univ, Department of Physics and Astronomy, Vanderbilt University, Vanderbilt Univ, Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA, Institute of Physics, Chinese Academy of Sciences, Department of Physics and Astronomy & Department of Electrical Engineering and Computer Science, Vanderbilt University, Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, Department of Electrical Engineering and Computer Science, Vanderbilt University, Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Vanderbilt University