Optimum HRTEM image contrast at 20 kV and 80 kV-Exemplified by graphene

Author(s)
Zonghoon Lee, Jannik C. Meyer, Harald Rose, Ute Kaiser
Abstract

The dependence of high-resolution transmission electron microscopy (HRTEM) image contrast of graphene on the adjustable parameters of an aberration-corrected microscope operated at 80 and 20 kV has been calculated and, for 80 kV, compared with measurements. We used density functional theory to determine the projected atom potential and obtained the image intensity by averaging over the energy distribution of the imaging electrons, as derived from the electron energy loss spectroscopy measurements. Optimum image contrast has been determined as a function of energy spread of the imaging electrons and chromatic aberration coefficient, showing that significant improvement of contrast can be achieved at 80 kV with the help of a monochromator, however at 20 kV only with chromatic aberration correction and bright atom contrast conditions.

Organisation(s)
Physics of Nanostructured Materials
External organisation(s)
Universität Ulm
Journal
Ultramicroscopy
Volume
112
Pages
39-46
No. of pages
8
ISSN
0304-3991
DOI
https://doi.org/10.1016/j.ultramic.2011.10.009
Publication date
2012
Peer reviewed
Yes
Austrian Fields of Science 2012
210006 Nanotechnology
Portal url
https://ucrisportal.univie.ac.at/en/publications/optimum-hrtem-image-contrast-at-20-kv-and-80-kvexemplified-by-graphene(5c2b3e37-35d4-488e-9e4e-2c67369ce291).html