Abstract
Scanning transmission electron microscopy (STEM) is the most widespread adopted tool for atomic scale characterization of two-dimensional (2D) materials. However, damage free imaging of 2D materials with electrons has remained problematic even with powerful low-voltage 60 kV-microscopes. An additional challenge is the observation of light elements in combination with heavy elements, particularly when recording fast dynamical phenomena. Here, we demonstrate that 2D WS2 suffers from electron radiation damage during 30 kV-STEM imaging, and we capture beam-induced defect dynamics in real-time by atomic electrostatic potential imaging using integrated differential phase contrast (iDPC)-STEM. The fast imaging of atomic electrostatic potentials with iDPC-STEM reveals the presence and motion of single sulfur atoms near defects and edges in WS2 that are otherwise invisible at the same imaging dose at 30 kV with conventional annular dark-field STEM, and has a vast speed and data processing advantage over electron detector camera based STEM techniques like electron ptychography.
Highlights
Two-dimensional materials are a hot topic of research for their large potential in future applications by virtue of their reduced dimensions and tunable properties
The two selected regions (Fig. 1a–d and e–h) contain various elements and defects: W, S2, VW, VS and V2S. All of these features are present in the atomic electrostatic potential images captured using integrated differential phase contrast (iDPC)-Scanning transmission electron microscopy (STEM), with clearly distinguishable contrast between S2, VS and V2S, matching quantitatively with image simulations (ESI, Fig. S2†)
We have demonstrated that the image quality of annular dark-field (ADF)-STEM deteriorates under these conditions, whereas atomic electrostatic potential imaging remains of high quality due to the inherent high sensitivity and noise suppression property of iDPC-STEM
Summary
Two-dimensional materials are a hot topic of research for their large potential in future applications by virtue of their reduced dimensions and tunable properties. We observe beam-induced radiation damage and defect dynamics in semiconducting 2D WS2 by recording atomic electrostatic potential movies with iDPC-STEM using a primary electron energy of 30 keV.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
