Impact of Atomic Oxygen on the Structure of Graphene Formed on Ir(111) and Pt(111)
Publikation/Tidskrift/Serie: Journal of Physical Chemistry C
Förlag: American Chemical Society
The effect of atomic oxygen adsorption on the structure and electronic properties of monolayer graphite (MG or graphene) grown on Pt(111) and Ir(111) has been studied using X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, and scanning tunneling microscopy. For comparison, the adsorption of atomic oxygen on highly oriented pyrolytic graphite has been studied under the same conditions. Graphene oxidation predominantly occurs through the formation of epoxy groups and causes atomic-scale buckling of the graphene lattice, as evidenced by an sp(2)-to-sp(3) bonding transformation. The different parts of the graphene/metal moire superstructure show different oxidation dynamics, with the initial formation of epoxy groups in the more bonding "pores". Upon 0 adsorption, the nearest C neighbors of epoxy groups get engaged in a stronger bonding with the substrate. As a result, the pores of the graphene mesh become attracted and effectively pinned to the substrate by the 0 atoms. A limited intercalation of oxygen under graphene is also probable. Annealing of the samples after oxygen exposure only partially recovers the original graphene structure and results in the formation of a dense pattern of quasi-periodic, nanometer-sized holes. Both the selective oxidization and the hole formation can be exploited for selective functionalization or tuning of the electronic properties.
- Physics and Astronomy
- ISSN: 1932-7447