High-resolution Powder Nano-Beam Diffraction in Scanning Electron Microscopy

0568572 - ÚPT 2023 CZ eng A - Abstrakt
Šlouf, Miroslav - Skoupý, Radim - Pavlova, Ewa - Krzyžánek, Vladislav
High-resolution Powder Nano-Beam Diffraction in Scanning Electron Microscopy.
16th Multinational Congress on Microscopy, 16MCM, 04-09 September 2022, Brno, Czech Republic. Book of abstracts. Brno: Czechoslovak Microscopy Society, 2022 - (Krzyžánek, V.; Hrubanová, K.; Hozák, P.; Müllerová, I.; Šlouf, M.). s. 76-77. ISBN 978-80-11-02253-2.
[Multinational Congress on Microscopy /16./. 04.09.2022-09.09.2022, Brno]
Grant CEP: GA TA ČR(CZ) TN01000008; GA ČR(CZ) GA21-13541S
Institucionální podpora: RVO:68081731 ; RVO:61389013
Klíčová slova: SEM * Powder NanoBeam Diffraction
https://www.16mcm.cz/wp-content/uploads/2022/09/16MCM-abstract-book.pdf

We have recently introduced a novel SEM method which yields powder electron diffraction patterns that are fully comparable to standard TEM/SAED powder diffractograms. This opens quite new possibilities in the field of SEM microscopy. The only hardware requirement is that the SEM microscope must be equipped with a pixelated detector of transmitted electrons. The pixelated detectors (2D-array detectors) for STEM-in-SEM have been commercialized recently. They can be used routinely to collect a high number of electron diffraction patterns from
individual nanocrystals and/or locations. This is called 4D-STEM, as we obtain 2D diffractogram for each pixel of the 2D scanning array. The 4D-STEM datasets are easy to collect, but the individual 4D-STEM diffractograms are difficult to analyze due to the random orientation of nanocrystalline material. In our method, all individual spotty diffractograms are combined into one composite powder diffraction pattern. Consequently, the method was called 4D-STEM/PNBD (Powder NanoBeam Diffraction). The final 4D-STEM/PNBD diffractogram can be analyzed easily by means of standard programs for TEM/SAED, such as ProcessDiffraction. To make the 4D-STEM/PNBD analysis as simple as possible, we developed a freeware Python program package STEMDIFF. The package converts 4D-STEM datasets to powder diffractograms with a minimal user input. The recent STEMDIFF version includes a fast entropy-based filtering module (selecting of strongly diffracting locations and ignoring the amorphous regions) and deconvolution module (reducing the effect of primary beam spread), which improve the 4D-STEM/PNBD resolution to a TEM/SAED level.
Trvalý link: https://hdl.handle.net/11104/0339862