First principles study of the stability of MXenes under an electron beam
|Author:||Ibragimova, Rina1; Lv, Zhong-Peng1; Komsa, Hannu-Pekka2|
1Department of Applied Physics, Aalto University, 00076 Aalto, Finland
2Microelectronics Research Unit, University of Oulu, 90014 Oulu, Finland
|Online Access:||PDF Full Text (PDF, 1.4 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2021042927947
Royal Society of Chemistry,
|Publish Date:|| 2021-04-29
Interactions between two-dimensional MXene sheets and electron beams of a (scanning) transmission electron microscope are studied by first-principles calculations. We simulated the knock-on sputtering threshold for Ti₃C₂ MXene sheets via ab initio molecular dynamics simulations and for five other MXenes (Ti₂C, Ti₂N, Nb₂C, Mo₂TiC₂, and Ti₃CN) approximately from defect formation energies. We evaluated the sputtering cross section and sputtering rates and based on those evaluated the surface composition. We find that at the exit surface and for “low” TEM energies H and F sputter at equal rates, but at “high” TEM energies the F is sputtered most strongly. In the entry surface, H sputtering dominates. The results were found to be largely similar for all studied MXenes, and although the sputtering thresholds varied between the different metal atoms the thresholds were always too high to lead to significant sputtering of the metal atoms. We simulated electron microscope images at the successive stages of sputtering and found that while it is likely difficult to identify surface groups based on the spot intensities, the local contraction of the lattice around O groups should be observable. We also studied MXenes encapsulated with graphene and found them to provide efficient protection from knock-on damage for all surface group atoms except H.
|Pages:||1934 - 1941|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
213 Electronic, automation and communications engineering, electronics
We acknowledge funding from the Academy of Finland under Project No. 311058.
|Academy of Finland Grant Number:||
311058 (Academy of Finland Funding decision)
© 2021 The Author(s). Published by the Royal Society of Chemistry. Open Access Article. Published on 17 February 2021. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.