Examination of 2D crystals in a low voltage SEM/STEM

0481591 - ÚPT 2018 RIV HR eng C - Conference Paper (international conference)
Mikmeková, Eliška - Frank, Luděk - Polčák, J. - Paták, Aleš - Lejeune, M.
Examination of 2D crystals in a low voltage SEM/STEM.
13th Multinational Congress on Microscopy: Book of Abstracts. Zagreb: Ruder Bošković Institute, Croatian Microscopy Society, 2017 - (Gajović, A.; Weber, I.; Kovačević, G.; Čadež, V.; Šegota, S.; Peharec Štefanić, P.; Vidoš, A.), s. 618-619. ISBN 978-953-7941-19-2.
[Multinational Congress on Microscopy /13./. Rovinj (HR), 24.09.2017-29.09.2017]
R&D Projects: GA TA ČR(CZ) TE01020118
Institutional support: RVO:68081731
Keywords : low voltage SEM/STEM * 2D crystals * contamination
OECD category: Coating and films

Development of new types of materials such as 2D crystals (graphene, MoS2, WS2, h-BN, etc.) requires emergence of new surface-sensitive techniques for their characterization. As regards the “surface” sensitivity, the (ultra) low energy electron microscopy can become a very powerful tool for true examination of these atom-thick materials, capable of confirming physical phenomena predicted to occur on their surfaces. Modern commercial scanning electron microscopes enable imaging and analyses by low energy electrons even at very high magnification. In the case of the SEM, resolution even below 1 nm can be achieved at low landing energy of electrons. Since specimen contamination increases with increasing electron dose and decreasing landing energy, specimen cleanness is a critical factor in obtaining meaningful data. A range of various specimen cleaning methods can be applied to selected samples. Typical cleaning methods, such as solvent rinsing, heating, bombarding with ions and plasma etching have their limitations. Electron-induced in situ cleaning procedure can be gentle, experimentally convenient and very effective for wide range of specimens. Even a small amount of hydrocarbon contamination can severely impact on the results obtained with low energy electrons, as illustrated in Figure 1A. During the scanning of surfaces by electrons, the image usually darkens because of a carbonaceous layer gradually deposited on the top from adsorbed hydrocarbon precursors.
Permanent Link: http://hdl.handle.net/11104/0277164