Factors limiting quantitative phase retrieval in atomic-resolution differential phase contrast scanning transmission electron microscopy using a segmented detector

• Published in: Ultramicroscopy Vol. 233; p. 113457
• Main Authors: Mawson, T., Taplin, D.J., Brown, H.G., Clark, L., Ishikawa, R., Seki, T., Ikuhara, Y., Shibata, N., Paganin, D.M., Morgan, M.J., Weyland, M., Petersen, T.C., Findlay, S.D.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2022
• Subjects: Differential phase contrast; Graphene; Image simulation; Quantitative scanning transmission electron microscopy; Segmented detectors; Differential phase contrast; Segmented detectors; Graphene; Quantitative scanning transmission electron microscopy; Image simulation
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2021.113457

Quantitative differential phase contrast imaging of materials in atomic-resolution scanning transmission electron microscopy using segmented detectors is limited by various factors, including coherent and incoherent aberrations, detector positioning and uniformity, and scan-distortion. By comparing experimental case studies of monolayer and few-layer graphene with image simulations, we explore which parameters require the most precise characterisation for reliable and quantitative interpretation of the reconstructed phases. Coherent and incoherent lens aberrations are found to have the most significant impact. For images over a large field of view, the impact of noise and non-periodic boundary conditions are appreciable, but in this case study have less of an impact than artefacts introduced by beam deflections coupling to beam scanning (imperfect tilt-shift purity). •Many factors affect the accuracy of quantitative DPC STEM with segmented detectors.•We show absolute-scale experiment/theory comparisons for a graphene case study.•Uncertainty in the coherent and incoherent lens aberrations most limit accuracy.•Scan artefacts and shot noise limit accuracy for larger fields of view.