Imaging atomic columns and interfaces in van der Waals heterostructures with electron ptychography
ORAL
Abstract
The development and applications of van der Waals (vdW) heterostructures, formed by successively stacking layers of 2D materials, has been significantly aided by high-resolution imaging using scanning transmission electron microscopy (STEM) [1]. However, high-throughput characterization of vdW heterostructures using STEM has been limited by poor sensitivity to light elements, lack of 3D information, and long image processing times.
Here, we apply electron ptychography, a coherent diffractive imaging technique [2], to image vdW heterostructures at atomic resolution. By collecting arrays of STEM diffraction patterns and performing computational reconstruction, the sample-induced electron phase shifts are plotted to obtain high-contrast images of twisted hexagonal boron nitride (h-BN) with lateral resolutions of 0.6 Å. Furthermore, we demonstrate 3D imaging of individual flakes and buried interfaces in twisted h-BN with a depth resolution of 2.5 nm [3]. By combining electron ptychography and deep learning, the imaging process can potentially be accelerated to enable real-time, high-throughput, atomic-resolution imaging of vdW heterostructures [4].
[1] X. Tian et al., Sci. Adv. 7, eabi6699 (2021).
[2] J. Miao et al., Nature 400, 342 (1999).
[3] C. M. O’Leary et al., Phys. Rev. Applied 22, 014016 (2024).
[4] D. J. Chang et al., Phys. Rev. Lett. 130, 016101 (2023).
Here, we apply electron ptychography, a coherent diffractive imaging technique [2], to image vdW heterostructures at atomic resolution. By collecting arrays of STEM diffraction patterns and performing computational reconstruction, the sample-induced electron phase shifts are plotted to obtain high-contrast images of twisted hexagonal boron nitride (h-BN) with lateral resolutions of 0.6 Å. Furthermore, we demonstrate 3D imaging of individual flakes and buried interfaces in twisted h-BN with a depth resolution of 2.5 nm [3]. By combining electron ptychography and deep learning, the imaging process can potentially be accelerated to enable real-time, high-throughput, atomic-resolution imaging of vdW heterostructures [4].
[1] X. Tian et al., Sci. Adv. 7, eabi6699 (2021).
[2] J. Miao et al., Nature 400, 342 (1999).
[3] C. M. O’Leary et al., Phys. Rev. Applied 22, 014016 (2024).
[4] D. J. Chang et al., Phys. Rev. Lett. 130, 016101 (2023).
*DOE BES: DE-SC0010378, STROBE NSF STC: DMR-1548924, ARO MURI: W911NF-18-1-0431.
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Publication: [1] C. M. O'Leary et al., Phys. Rev. Applied 22, 014016 (2024).
[2] D. J. Chang et al., Phys. Rev. Lett. 130, 016101 (2023).
Presenters
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Haozhi Sha
- University of California, Los Angeles