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O: Fachverband Oberflächenphysik
O 41: Graphene III
O 41.2: Vortrag
Mittwoch, 28. März 2012, 10:45–11:00, MA 041
Morphology dependent kinetics of oxygen intercalation into graphene/Ir(111) — •Ulrike Schröder1, Elin Grånäs2, Timm Gerber1, Jan Knudsen2, Mohammad Arman2, Karina Schulte3, Jesper Andersen2, and Thomas Michely1 — 1II. Phys. Institut, Universität zu Köln — 2Division of Synchrotron Radiation Research, Lund University — 3MAX-Lab, Lund University
Stability of graphene in the presence of gases and at elevated temperatures is of crucial importance for various applications, including its use as a template for well-ordered cluster growth [1].
We investigate the morphology and temperature dependence of oxygen intercalation into graphene/Ir(111) by STM measurements, complementary to our XPS results. A full monolayer of graphene grown with the TPG+CVD method [2] is remarkably stable against O2 exposure. No intercalation takes place and etching of graphene is only observed at temperatures above 700 K. In STM the onset of etching is visible by hexagonal etch holes in the graphene after O2 exposure at 740 K. In contrast, O intercalates readily at 400 K under large graphene flakes that cover only 50% of the surface. Surprisingly, smaller flakes resist intercalation at 400 K. Details of the intercalation kinetics can be distinguished by analyzing differences in moiré contrast and apparent graphene heights that are due to oxygen intercalation. Decoupling of graphene from the metal substrate is directly investigated through the effect intercalation has on the formation of metal cluster lattices. [1] N’Diaye et al.; NJP 2009, 11, 103045. [2] van Gastel et al.; APL 2009, 95, 121901.