Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 107: Graphene: Electronic Structure (jointly with O, HL)
TT 107.11: Talk
Thursday, March 19, 2015, 17:30–17:45, MA 041
Embedding graphene quantum dots into hexagonal boron nitride — Ferdinand Farwick zum Hagen1, Caio Silva1, Christoph Schlueter2, Nicolae Atodiresei3, Wouter Jolie1, Daniela Dombrowski1, Antonio J. Martinez-Galera1, Domenik Zimmermann1, Ulrike Schröder1, Vasile Caciuc3, Thomas Michely1, Stefan Blügel3, Tien-Lin Lee2, and •Carsten Busse1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Diamond Light Source, Didcot, UK — 3Peter Grünberg Institute, Forschungszentrum Jülich, Germany
Graphene (gr) nanostructures can be stabilized by embedding them into an insulating matrix. Hexagonal boron nitride (hBN) is especially suited as it is isostructural to graphene, and dangling C bonds can be satisfied by B and N. In this study, we used sequential epitaxial growth of gr and hBN on Ir(111) to embed graphene quantum dots (GQDs).
First, we investigate pristine hBN/Ir(111) with special attention to the hBN-substrate interaction which is characterized by the local varying layer height as determined with x-ray standing waves (XSW), complemented by density functional theory (DFT) calculations. Distinct differences with respect to gr/Ir(111) are found: A stronger corrugation within the moiré and an enhanced chemical interaction in the strongly bound parts of the supercell. Second, the edge atoms of GQDs on Ir(111) are investigated and an enhanced C-substrate interaction is found. Third, the chemical and structural changes at these edges upon embedding in hBN are probed. The in-plane structure is analyzed using scanning tunneling microscopy (STM).