Analysis of Point Defects in Graphene Using Low Dose Scanning Transmission Electron Microscopy Imaging and Maximum Likelihood Reconstruction (Phys. Status Solidi B 11/2017). Issue 11 (16th November 2017)

• Record Type: Journal Article
• Authors: Kramberger, Christian; Mittelberger, Andreas; Hofer, Christoph; Meyer, Jannik C.
• Is Part Of: Physica status solidi. Volume 254:Issue 11(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-11-16
• Subjects: Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201770257
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : With today's aberration‐corrected transmission electron microscopes it is possible to image the precise atomic positions in materials. However, so far this has required exposing the material to extremely high doses of electrons – often exceeding one million electrons per square angstrom – which also often leads to beam‐induced changes of the structure. In the article by Kramberger et al. (no.1700176 ), it is shown how images of defect configurations in graphene can be extracted from a large number of very low dose exposures, with two orders of magnitude lower dose than typically used for atomic‐resolution scanning transmission electron microscopy. In this approach, the dose is distributed over a large number of repeatedly occurring defects, and then representative images are obtained via a numerical algorithm. While the idea to distribute the dose over many identical copies of an object is inspired by methods from structural biology, a maximum likelihood reconstruction algorithm was applied for the first time to the individual atoms in a material. The defect population as found via low‐dose imaging is indeed different from that reported in earlier studies. The cover image shows partly the original low‐dose data, and partly the reconstructed images of defects in graphene.