Finding the Atoms that Matter in Functional Materials: Adventures with 4D-STEM

Session

EMAG Plenary Talk: Professor Joanne Etheridge - Finding the atoms that matter in functional materials - adventures with 4D-STEM

Authors

Professor Joanne Etheridge (1)

Affiliations

1. Monash Centre for Electron Microscopy and Dept of Materials Science and Engineering

Keywords

4D-STEM, scanning transmission electron microscopy, convergent beam electron diffraction, perovskite, nanoparticles, plasmons.

Abstract text

In many materials, from solar cells to computer chips, it can be a small number of atoms located in critical positions that give the material its distinctive properties. These are the atoms that matter! How can we detect and locate them? 

Scanning transmission electron microscopy (STEM) is a powerful tool for characterising materials at the atomic scale. In scanning transmission electron microscopes, a tiny electron probe is scanned across the specimen and at each position of the probe the distribution of scattered electrons is detected. 

In conventional STEM, annular or disc detectors are used, which sum the scattered electron distribution over a certain angular range, delivering one or two bytes of specimen information per probe position. 

In so-called “4D-STEM”, pixel array detectors are used, which allow the full angular distribution of scattered electrons to be recorded, delivering up to a million bytes of specimen information per probe position. 4D-STEM represents a revolution in STEM, providing an unprecedented wealth of information about atomic-scale volumes of specimen. This opens entirely new possibilities for detecting the “atoms that matter” in functional materials. 

This talk will describe different approaches for extracting desired specimen information from the huge 4D-STEM datasets and will illustrate these with applications to functional materials, from photoactive perovskites to plasmonic nanoparticles.