Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 4: Graphene I
O 4.10: Talk
Monday, March 26, 2012, 12:45–13:00, MA 041
Ion Beam induced Defects in Graphene — •Sebastian Standop1, Georgia Lewes-Malandrakis1, Charlotte Herbig1, Ossi Lehtinen2, Arkady V. Krasheninnikov2, Thomas Michely1, and Carsten Busse1 — 1II. Physikalisches Instiut, Universität zu Köln — 2Materials Physics Division, University of Helsinki, Finland
We explore ion irradiation as a tool to intentionally create defects in graphene. Defects not only alter graphene’s structure, but were predicted to significanty affect its electronic properties [1]. Ion irradiation of graphene grown epitaxially on Ir(111) was conducted at room temperature with 1-15 keV noble gas ions (He, Ne, Ar, Xe) at an angle of 75∘ with respect to the surface normal. While for low energies and light ions only single holes or the absence of defect patterns are observed, for ion energies beyond a few keV and heavier ions pronounced damage patterns in great variety are observed as surface damage in scanning tunneling microscopy. These patterns consist of sequences of holes in graphene, some of them decorated by bright protrusions, with a maximum length exceeding 40 nm. We interpret the holes as to result from multiple scattering of the ions in between graphene and the Ir(111) surface. The protrusions are assumed to show Ir adatoms under the graphene layer created by the energy deposition of the ion to the substrate. Our interpretation is supported by corresponding molecular dynamics simulations of ion impacts in conjunction with ab initio density function theory calculations as well as annealing studies performed in situ. [1] M. M. Ugeda et al., PRL 104, 096804 (2010)