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O: Fachverband Oberflächenphysik

O 7: Graphene I: Structure and Growth (joint session O/TT)

O 7.9: Vortrag

Montag, 1. April 2019, 12:45–13:00, H24

Intercalation dynamics of sulfur underneath graphene on Ru(0001) — •Lars Buß¹, Jens Falta^1,2, and Jan Ingo Flege³ — ¹Institute for Solid State Physics, University of Bremen, Germany — ²MAPEX Center for Materials and Processes, University of Bremen, Germany — ³Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Germany

It is known that the binding of epitaxially grown graphene to the substrate has a detrimental effect on its electronic properties. This is especially true for the strong binding to various transition metals and particularly ruthenium. However, via intercalation the interlayer coupling can be lifted and its unique electronic properties can be restored. Therefore, we have investigated the interaction of sulfur with single-layer graphene grown on Ru(0001) via surface segregation and CVD of ethylene under UHV conditions with in situ low-energy electron microscopy (LEEM) and micro-diffraction (µLEED). At elevated temperature and under dimethyl disulfide background pressure, we observe that sulfur intercalates through the open edges of the graphene islands. Prolonged exposure to sulfur induces wrinkling of the graphene islands, consistent with substantial relief of tensile strain after successful sulfur insertion underneath the graphene. It can be seen that the intercalation dynamics are both dependent on the temperature during intercalation and the preparation method of the graphene sheets. Furthermore, darkfield imaging and µLEED of the intercalated graphene reveal a graphene induced improved ordering of sulfur underneath.