Powder nano-beam diffraction in scanning electron microscope: fast and simple method for analysis of nanoparticle crystal structure

0541840 - ÚMCH 2022 RIV CH eng J - Článek v odborném periodiku
Šlouf, Miroslav - Skoupý, Radim - Pavlova, Ewa - Krzyžánek, Vladislav
Powder nano-beam diffraction in scanning electron microscope: fast and simple method for analysis of nanoparticle crystal structure.
Nanomaterials. Roč. 11, č. 4 (2021), č. článku 962. E-ISSN 2079-4991
Grant CEP: GA ČR(CZ) GA21-13541S; GA TA ČR(CZ) TN01000008
Institucionální podpora: RVO:61389013 ; RVO:68081731
Klíčová slova: nanoparticle analysis * powder nanobeam electron diffraction * 4D-STEM/PNBD
Obor OECD: Analytical chemistry; Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) (UPT-D)
Impakt faktor: 5.719, rok: 2021
Způsob publikování: Open access
https://www.mdpi.com/2079-4991/11/4/962

We introduce a novel scanning electron microscopy (SEM) method which yields powder electron diffraction patterns. The only requirement is that the SEM microscope must be equipped with a pixelated detector of transmitted electrons. The pixelated detectors for 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 four-dimensional scanning transmission electron microscopy (4D-STEM), as we obtain two-dimensional (2D) information for each pixel of the 2D scanning array). Nevertheless, the individual 4D-STEM diffractograms are difficult to analyze due to the random orientation of nanocrystalline material. In our method, all individual diffractograms (showing randomly oriented diffraction spots from a few nanocrystals) are combined into one composite diffraction pattern (showing diffraction rings typical of polycrystalline/powder materials). The final powder diffraction pattern can be analyzed by means of standard programs for TEM/SAED (Selected-Area Electron Diffraction). We called our new method 4D-STEM/PNBD (Powder NanoBeam Diffraction) and applied it to three different systems: Au nano-islands (well diffracting nanocrystals with size ~20 nm), small TbF3 nanocrystals (size < 5 nm), and large NaYF4 nanocrystals (size > 100 nm). In all three cases, the STEM/PNBD results were comparable to those obtained from TEM/SAED. Therefore, the 4D-STEM/PNBD method enables fast and simple analysis of nanocrystalline materials, which opens quite new possibilities in the field of SEM.
Trvalý link: http://hdl.handle.net/11104/0319354