Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 98: Graphene I: Growth, Structure and Substrate Interaction (joint session O/TT)
O 98.2: Talk
Thursday, March 19, 2020, 10:45–11:00, GER 37
Graphene/S/Ru(0001): a model system for studying intercalation — •Lars Buß1,2, Jens Falta2,3, Moritz Ewert1, Polina Sheverdyaeva4, Paolo Moras4, and Jan Ingo Flege1 — 1Applied Physics and Semiconductor Spectroscopy, BTU Cottbus-Senftenberg, Cottbus, Germany — 2Institute for Solid State Physics, University of Bremen, Bremen, Germany — 3MAPEX Center for Materials and Processes, University of Bremen, Bremen, Germany — 4Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste, Italy
The epitaxial growth of single-layer graphene on transition-metal substrates enables the growth of micrometer-sized islands with excellent crystalline quality, but the possibly strong binding to the substrate has proven detrimental to its materials properties. However, intercalation of foreign atoms lifts the interlayer coupling, restoring its unique electronic structure. We have investigated the intercalation of sulfur underneath graphene on Ru(0001) with low-energy electron microscopy (LEEM) and micro-diffraction (µLEED). We find that sulfur deposited from a molecular precursor at elevated temperatures intercalates through the edge of the island, eventually leading to wrinkles in the graphene. Intriguingly, the overlaying graphene limits the number of possible S/Ru(0001) reconstructions below, preventing the formation of less dense reconstructions like the p(2× 2)-S and (√3× √3)-S surface phases. Intensity-voltage LEEM and angle-resolved photoemission (ARPES) prove the free-standing character of the sulfur intercalated graphene, which is found to be p-doped by 380 meV.