A new method of scanning electron microscopy
The Department of Polymer Morphology, in collaboration with the Institute of Scientific Instruments, has developed a new method of scanning electron microscopy (SEM). The new method, which enables to obtain powder electron diffraction patterns in a SEM microscope equipped with a pixelated detector of transmitted electrons, was recently featured in the journal Nanomaterials.
"Since 2015, I have been intensively devoted to electron diffraction due to the analysis of inorganic nanoparticles for functional polymer systems developed in the Department of Polymer Particles of our Institute. While we were performing electron diffraction in a standard way using a transmission electron microscope (TEM) at IMC, the company ThermoFischer Scientific Brno (TFS) was developing the pixelated detectors for transmitted electrons in SEM microscopes. One of the very first detectors of this type was installed in 2020 at our collaborating Institute of Scientific Instruments (ISI),” describes the head of the Department of Polymer Morphology, Dr. Miroslav Šlouf.
The basic idea of how to use the newly developed pixelated detectors for a fast and simple analysis of nanocrystals in SEM arose during a discussion between the first two authors of the publication at the meeting of the National Competence Center in Brno at the end of 2020 (key partners within the Center are ISI and TFS).
Briefly, the new method, which was called 4D-STEM/PNBD, can average a large, complex, four-dimensional data file from a pixelated detector into a single powder diffractogram. "After we verified in the literature and other available sources that a similar method exists in TEM, but not in SEM microscopes with given hardware configuration, we started with pilot experiments. Because manual data processing was practically impossible, we have developed our own, fast and simple software. Speed of our program package (called STEMDIFFF) was important due to extremely large 4D datasets and simplicity was due to the potential users – there are plenty of over-complicated things in the world," says Dr. Šlouf.
The new method could be developed and published thanks to the long-term, well-established collaboration among the IMC, ISI and TFS within the Center of Competence and the following National Center of Competence. "I would not have been able to start with extensive and completely new topic at all, if I hadn’t had a reliable team within the department, with which I was could manage other internal and external projects that have their own problems, complications and deadlines," adds Dr. Šlouf.