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Title: Interaction of epitaxial silicene with overlayers formed by exposure to Al atoms and O{sub 2} molecules

As silicene is not chemically inert, the study and exploitation of its electronic properties outside of ultrahigh vacuum environments require the use of insulating capping layers. In order to understand if aluminum oxide might be a suitable encapsulation material, we used high-resolution synchrotron photoelectron spectroscopy to study the interactions of Al atoms and O{sub 2} molecules, as well as the combination of both, with epitaxial silicene on thin ZrB{sub 2}(0001) films grown on Si(111). The deposition of Al atoms onto silicene, up to the coverage of about 0.4 Al per Si atoms, has little effect on the chemical state of the Si atoms. The silicene-terminated surface is also hardly affected by exposure to O{sub 2} gas, up to a dose of 4500 L. In contrast, when Al-covered silicene is exposed to the same dose, a large fraction of the Si atoms becomes oxidized. This is attributed to dissociative chemisorption of O{sub 2} molecules by Al atoms at the surface, producing reactive atomic oxygen species that cause the oxidation. It is concluded that aluminum oxide overlayers prepared in this fashion are not suitable for encapsulation since they do not prevent but actually enhance the degradation of silicene.
Authors:
;  [1] ; ; ; ;  [2]
  1. Japan Advanced Institute of Science and Technology, School of Materials Science, Nomi, Ishikawa 923-1292 (Japan)
  2. MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands)
Publication Date:
OSTI Identifier:
22304364
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 20; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM OXIDES; ATOMS; CHEMICAL STATE; CHEMISORPTION; DEPOSITION; DOSES; ENCAPSULATION; EPITAXY; FILMS; INTERACTIONS; LAYERS; MOLECULES; OXYGEN; PHOTOELECTRON SPECTROSCOPY; ZIRCONIUM BORIDES