Fabrication and characterization of boron-terminated tetravacancies in monolayer hBN using STEM, EELS and electron ptychography

Journal Article · Fri Dec 26 00:00:00 UTC 2025 · Ultramicroscopy

DOI: https://doi.org/10.1016/j.ultramic.2025.114305 · OSTI ID:3017588

Byrne, Dana O.  ^[1]; Ribet, Stephanie M.  ^[2]; Kepaptsoglou, Demie  ^[3]; Ramasse, Quentin M.  ^[4]; Ophus, Colin  ^[5]; Allen, Frances I.  ^[1]

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1. University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Molecular Foundry
2. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Molecular Foundry
3. SciTech Daresbury Campus (United Kingdom). SuperSTEM Laboratory; University of York (United Kingdom)
4. SciTech Daresbury Campus (United Kingdom). SuperSTEM Laboratory; University of Leeds (United Kingdom)
5. Stanford University, CA (United States)

Tetravacancies in monolayer hexagonal boron nitride (hBN) with consistent edge termination (boron or nitrogen) form triangular nanopores with electrostatic potentials that can be leveraged for applications such as selective ion transport and neuromorphic computing. In order to quantitatively predict the properties of these structures, an atomic-level understanding of their local electronic and chemical environments is required. Moreover, robust methods for their precision manufacture are needed. Here we use electron irradiation in a scanning transmission electron microscope (STEM) at a high dose rate to drive the formation of boron-terminated tetravacancies in monolayer hBN. Characterization of the defects is achieved using aberration-corrected STEM, monochromated electron energy-loss spectroscopy (EELS), and electron ptychography. Z-contrast in STEM and chemical fingerprinting by core-loss EELS enable identification of the edge terminations, while electron ptychography gives insight into structural relaxation of the tetravacancies and provides evidence of enhanced electron density around the defect perimeters indicative of bonding effects.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: National Energy Research Scientific Computing Center (NERSC); National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 3017588
• Journal Information: Ultramicroscopy, Journal Name: Ultramicroscopy Vol. 282; ISSN 0304-3991
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English