Thickness dependence of scattering cross-sections in quantitative scanning transmission electron microscopy

G T Martinez; K H W van den Bos; M Alania; P D Nellist; S Van Aert

doi:10.1016/j.ultramic.2018.01.005

Thickness dependence of scattering cross-sections in quantitative scanning transmission electron microscopy

Ultramicroscopy. 2018 Apr:187:84-92. doi: 10.1016/j.ultramic.2018.01.005. Epub 2018 Jan 31.

Authors

G T Martinez¹, K H W van den Bos¹, M Alania¹, P D Nellist², S Van Aert³

Affiliations

¹ Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020, Antwerp, Belgium.
² Department of Materials, Oxford University, Parks Road, Oxford OX1 3PH, United Kingdom.
³ Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020, Antwerp, Belgium. Electronic address: sandra.vanaert@uantwerpen.be.

PMID: 29413416
DOI: 10.1016/j.ultramic.2018.01.005

Abstract

In quantitative scanning transmission electron microscopy (STEM), scattering cross-sections have been shown to be very sensitive to the number of atoms in a column and its composition. They correspond to the integrated intensity over the atomic column and they outperform other measures. As compared to atomic column peak intensities, which saturate at a given thickness, scattering cross-sections increase monotonically. A study of the electron wave propagation is presented to explain the sensitivity of the scattering cross-sections. Based on the multislice algorithm, we analyse the wave propagation inside the crystal and its link to the scattered signal for the different probe positions contained in the scattering cross-section for detector collection in the low-, middle- and high-angle regimes. The influence to the signal from scattering of neighbouring columns is also discussed.

Keywords: ADF STEM; Electron scattering; Image simulation; Quantitative STEM.

Publication types

Research Support, Non-U.S. Gov't