Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 94: Focus Session: Proximity Effects in Epitaxial Graphene I

O 94.8: Talk

Thursday, March 21, 2024, 17:15–17:30, MA 141

Spatially Resolved Sn Intercalation of Epitaxial Buffer Layer of Graphene on SiC — •Benno Harling and Martin Wenderoth — IV. Physical Institute, Georg-August-University Göttingen, Germany

Intercalation, the insertion of atoms into a layered material such as graphene, has been shown to be a versatile means of altering electronic properties through proximity. While intercalation is typically discussed as a spatially homogeneous process, our study focusses on the inhomogeneities on the mesoscopic scale. An investigation of a partially intercalated epitaxial graphene buffer layer with tin was conducted using Kelvin Probe Force Microscope (KPFM). √3 × √3 and 1 × 1 phases of the intercalated tin can be discriminated as doping on the graphene layer corresponding to a specific shift in the work function. This allows to locate and quantify the different intercalation phases as well as the transition to the pristine buffer layer on a sub-micrometer scale. This opens insight into the diffusion of the intercalated atoms, i.e., the intercalation dynamics on this scale. Gradients from fully intercalated areas to the pristine buffer layer are observed and correlated with the topographic information. Our results show the strong impact of substrate steps as a significant boundary for the diffusion process, more specifically diffusion of Sn mainly happens on a terrace or via pin hole like channels across steps.

Keywords: Epitaxial Graphene; Tin Intercalation; Silicon Carbide; Kelvin Probe Force Microscopy; Work Function