Ultra-low energy SEM/STEM of graphene

0501301 - ÚPT 2019 GB eng A - Abstract
Frank, Luděk - Mikmeková, Eliška
Ultra-low energy SEM/STEM of graphene.
19th World Congress on Material Science and Engineering. Proceedings. Vol. S7. London: Omics International, 2018. s. 141-142. ISSN 2169-0022.
[World Congress on Materials Science and Engineering /19./. 11.06.2018-13.06.2018, Barcelona]
Institutional support: RVO:68081731
Keywords : ultra-low energy * SEM * STEM * graphene
OECD category: Nano-materials (production and properties)

Graphene sheets, including multilevel stacks, are nearly fully transparent for electrons at energies standard in electron microscopes. Graphene has even been considered an ideal substrate for the deposition of, for example, organic macromolecules for their observation in a scanning (transmission) electron microscope (SEM/STEM). The cathode lens principle with a negatively biased sample in the SEM/STEM enables one to obtain an arbitrarily low energy of electrons securing an ultimately reduced interaction volume providing the image information. The image contrast has been found to be sufficient for distinguishing graphene flakes at tens and units of eV in the STEM, and the electron transmissivity surprisingly showed values in units of percent only in this energy range. Expectations based on the usual extension of the inelastic mean free path of electrons below some 50 eV have not been confirmed.
Permanent Link: http://hdl.handle.net/11104/0293291