Etching of graphene on Ir(111) with molecular oxygen

Research output: Contribution to journalArticle

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.

Details

Authors
  • Ulrike A. Schroeder
  • Elin Grånäs
  • Timm Gerber
  • Mohammad A Arman
  • Antonio J. Martinez-Galera
  • Karina Schulte
  • Jesper N Andersen
  • Jan Knudsen
  • Thomas Michely
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Other Physics Topics

Keywords

  • Graphene, Oxygen etching, Pentagon-heptagon defect, STM, XPS, TPD
Original languageEnglish
Pages (from-to)320-331
JournalCarbon
Volume96
Publication statusPublished - 2016
Publication categoryResearch
Peer-reviewedYes