Combining quantitative ADF STEM with SiNx membrane-based MEMS devices: A simulation study with Pt nanoparticles

• Published in: Ultramicroscopy Vol. 231; p. 113270
• Main Authors: MacArthur, Katherine E., Clement, Antoine, Heggen, Marc, Dunin-Borkowski, Rafal E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2021
• Subjects: ADF STEM; Atom Counting; Cross Sections; In-situ; Nanoparticles; Quantification; Nanoparticles; Cross Sections; Quantification; In-situ; ADF STEM; Atom Counting
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2021.113270

•The effect if Si3N4 membranes on the accuracy of atom counting for ADF STEM.•At 80kV the scattering is too high, only +/- 2 atom accuracy is possible.•At 200kV/300kV single atom precision is possible.•Si3N4 membranes above the sample systematically lower image intensity in the image. Computer simulations are used to assess the influence of a 20-nm-thick SiNx membrane on the quantification of atomic-resolution annular dark-field (ADF) scanning transmission electron microscopy images of Pt nanoparticles. The discussions include the effect of different nanoparticle/membrane arrangements, accelerating voltage, nanoparticle thickness and the presence of adjacent atomic columns on the accuracy with which the number of Pt atoms in each atom column can be counted. The results, which are based on the use of ADF scattering cross-sections, show that an accuracy of better than a single atom is attainable at 200 and 300 kV. At 80kV, the scattering in a typical SiNx membrane is sufficiently strong that the best possible atom counting accuracy is reduced to +/- 2 atoms. The implications of the work for quantitative studies of Pt nanoparticles imaged through SiNx membranes are discussed.