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O: Fachverband Oberflächenphysik
O 17: Poster Monday: 2D Materials
O 17.4: Poster
Montag, 1. April 2019, 17:45–20:00, Poster F
Local Manipulation and Exfoliation of Graphene from an HOPG Surface using a Scanning Tunneling Microscope — •Suchetana Sarkar1, Christoph Dobner1, Andreas Raabgrund2, and Axel Enders1 — 1Universitaet Bayreuth, Bayreuth,Deutschland — 2Friedrich-Alexander-Universitaet Erlangen-Nürnberg, Erlangen, Deutschland
Among the several methods in which graphene can be fabricated, the manipulation of graphitic surfaces has long been of interest. Here, we demonstrate a reliable method of forming Single Layer Graphene (SLG) and Few Layer Graphene (FLG) through the local electro-exfoliation of the top layers of HOPG. Using an ambient scanning tunneling microscope (STM), we create triangular graphene flakes by scanning perpendicular to a step edge which can then be peeled back via a voltage ramp, thereby detaching it from the substrate.These triangular flakes are of interest as they behave like isolated graphene sheets and can therefore be studied to gain insights into the correlation between surface morphology and electronic properties and the possibility to tune local conductance by surface manipulation. Under certain conditions, the creation of graphene flakes near macroscopic defects and backfolding onto the HOPG terrace, led to the formation of Moiré patterns. By using 1,2,4-Trichlorobenzene to intercalate the layers of HOPG in solution, Moiré lattices as large as 200 nm were achieved. Subsequent STM studies show that these exhibit different lattice periodicites, from which we can determine precisely how the graphene layers are aligned.