Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 78: Graphene: Preparation and characterization I (O, jointly with HL, TT)
HL 78.5: Vortrag
Donnerstag, 14. März 2013, 11:30–11:45, H17
High-Temperature STM of the Ordering of an Amorphous Carbon Layer into Graphene on Ru(0001) — Sebastian Günther1, Sebastian Dänhardt2, •Martin Ehrensperger2, Patrick Zeller2, Stefan Schmitt3, and Joost Wintterlin2 — 1Chemie Department, Technische Universität München, Germany — 2Department Chemie, Ludwig-Maximilians-Universität München, Germany — 3SPECS GmbH, Voltastr. 5, D-13355 Berlin, Germany
An amorphous carbon layer was prepared on Ru(0001) by chemical vapor deposition of ethylene at about 650 K. High-Temperature Scanning Tunneling Microscopy (HTSTM), Low Energy Electron Diffraction and Temperature Programmed Desorption measurements were used to characterize the layer and its formation. The obtained carbon layer then served as amorphous precursor in an ordering transition towards graphene. At temperatures between 920 and 950 K the layer transformed into graphene which was indicated by the evolving moiré pattern. The ordering was monitored in situ by HTSTM. The observations revealed a unique mechanism involving mobile, small topographic holes that move through the disordered carbon layer leaving graphene behind. The transport of carbon monomers mediated by these holes opens a low-energy pathway for the ordering transition. In a dense packed graphene layer this mechanism is impossible which can explain the problems of healing defects in chemically synthesized graphene.