Universität zu Köln

Schroeder, Ulrike A., Granas, Elin ORCID: 0000-0001-5247-7589, Gerber, Timm, Arman, Mohammad A., Martinez-Galera, Antonio J., Schulte, Karina, Andersen, Jesper N., Knudsen, Jan and Michely, Thomas (2016). Etching of graphene on Ir(111) with molecular oxygen. Carbon, 96. S. 320 - 332. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 1873-3891

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Abstract

The mechanisms for oxygen etching of graphene on Ir(111) are uncovered through a systematic variation of the graphene morphology - ranging from an impermeable graphene layer to graphene nanoflakes - and the application of complementary experimental methods, including scanning tunneling microscopy, X-ray photoelectron spectroscopy, and temperature programmed desorption. Associated with a strong variation in the onset temperature for etching, we find a fundamental difference in the onset of etching for an impermeable layer and for graphene flakes. For the impermeable graphene layer etching is shown to nucleate at graphene pentagon heptagon point defects through molecules impinging from the gas phase. For graphene flakes the nucleation problem is absent due to the existence of edges in contact with the metallic substrate. The substrate enables dissociative chemisorption of oxygen, which can then diffuse as atomic oxygen to the graphene edge. Our results show that intercalation of oxygen is neither a necessary condition nor of specific relevance for etching. Based on our analysis, a quantitative estimate for the activation energy and attempt frequency of the elementary etch process in flake etching on Ir(111) is provided. (C) 2015 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schroeder, Ulrike A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Granas, Elin UNSPECIFIED orcid.org/0000-0001-5247-7589 UNSPECIFIED Gerber, Timm UNSPECIFIED UNSPECIFIED UNSPECIFIED Arman, Mohammad A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Martinez-Galera, Antonio J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schulte, Karina UNSPECIFIED UNSPECIFIED UNSPECIFIED Andersen, Jesper N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Knudsen, Jan UNSPECIFIED UNSPECIFIED UNSPECIFIED Michely, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-293530
DOI:	10.1016/j.carbon.2015.09.063
Journal or Publication Title:	Carbon
Volume:	96
Page Range:	S. 320 - 332
Date:	2016
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	1873-3891
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EPITAXIAL GRAPHENE; OXIDATION; INTERCALATION; MECHANISM; MOIRE; DESORPTION; LATTICE; GROWTH; EDGES; SCALE Multiple languages Chemistry, Physical; Materials Science, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/29353