Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 61: Graphene II: Adsorption, Intercalation and Doping
O 61.2: Talk
Wednesday, March 9, 2016, 15:15–15:30, S053
A nanodiamond superlattice on graphene/Ir(111) — •Charlotte Herbig1, Philipp Valerius1, Timo Knispel1, Sabina Simon1, 2, Ulrike A. Schröder1, Antonio J. Martínez-Galera1, Mohammad A. Arman3, Christian Teichert1, 4, Jan Knudsen3, 5, Arkady V. Krasheninnikov6, 7, and Thomas Michely1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Department of Physics, University of Konstanz, Germany — 3Division of Synchrotron Radiation Research, Lund University, Sweden — 4Institute of Physics, Montanuniversität Leoben, Austria — 5MAX IV Laboratory, Lund, Sweden — 6Department of Applied Physics, Aalto University, Finland — 7Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Germany
Atomic C deposition onto the graphene moiré with Ir(111) leads in a broad temperature range from 130 K to 550 K to the formation of a nanodiamond superlattice with one C cluster per moiré unit cell. The size of the C clusters is tunable between about 20 and 150 C atoms. For deposited amounts exceeding about 200 C atoms per moiré unit cell the ordering is lost, but still nanodiamond structures remain. The nanodiamond superlattice is thermally stable up to 800 K. Annealing to higher temperatures results in C intercalation and eventually bilayer graphene formation. On the basis of scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory a model for C cluster formation, structure, stability, and decay is developed. Based on the generality of our model, we speculate that nanodiamonds may form on other moirés of 2D materials with their substrate.