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Electron reflectivity from clean and oxidized steel surface
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SYSNO ASEP 0565515 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Electron reflectivity from clean and oxidized steel surface Author(s) Mikmeková, Šárka (UPT-D) RID, SAI, ORCID
Aoyama, T. (JP)
Paták, Aleš (UPT-D) RID, ORCID, SAI
Zouhar, Martin (UPT-D) ORCID, RID, SAINumber of authors 4 Source Title Surface and Interface Analysis. - : Wiley - ISSN 0142-2421
Roč. 54, č. 6 (2022), s. 667-676Number of pages 10 s. Publication form Print - P Language eng - English Country GB - United Kingdom Keywords density-functional theory ; local density of states ; low-energy electron microscopy ; mirror microscopy ; surface potential Subject RIV JA - Electronics ; Optoelectronics, Electrical Engineering OECD category Materials engineering R&D Projects TN01000008 GA TA ČR - Technology Agency of the Czech Republic (TA ČR) Method of publishing Limited access Institutional support UPT-D - RVO:68081731 UT WOS 000760336000001 EID SCOPUS 85125073168 DOI https://doi.org/10.1002/sia.7079 Annotation This paper aims to elucidate the effect of an air-formed native oxide covering mild steel surface on the contrast in the scanning electron microscopy (SEM) images obtained with the landing energy from 5 keV down to 0 eV. Part of the mild steel surface was in-situ cleaned by Ar+ ion sputtering process in order to remove native oxide from the surface. It enabled us to observe the oxide-free and the naturally oxidized area on the mild steel surface simultaneously in the SEM micrographs. Presence of the native oxide starts to play a role in the SEM images acquired at landing energy below roughly 3 keV. Contrast between differently oriented grains situated inside the area covered by the native oxide starts to be negligible with landing energy decreasing below 3 keV, up to some ultra-low values where the contrast increases again. Total reflectivity contrast between the clean and the oxidized area increases exponentially with landing energy decreasing below 3 keV. The reflectivity-versus-energy curves of the cleaned and the naturally oxidized mild steel surface are markedly different. The reflectivity of the electrons is correlated with the density of states (DOS), as is demonstrated at very low landing energies. Sensitivity of the very low-energy electrons to the electronic structure was verified by comparison of the experimental data with the simulations of reflectivities, band structure, and DOS. The theoretical predictions are based on the density-functional theory calculations and they have been performed in energy range corresponding to specular reflectivities of the Fe-BCC (001) orientation. We have also observed that close to the mirror condition, that is, near-zero landing energies, the primary electrons become sensitive to the surface potential differences caused by the work function differences of clean and native oxide-covered steel surfaces. Workplace Institute of Scientific Instruments Contact Martina Šillerová, sillerova@ISIBrno.Cz, Tel.: 541 514 178 Year of Publishing 2023 Electronic address https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/sia.7079
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