Open AccessAtomic force microscopy phase imaging of epitaxial graphene films
Author(s) -
Francesco Lavini,
Filippo Cellini,
Martin Rejhon,
Jan Kunc,
Claire Berger,
Walt de Heer,
Elisa Riedo
Publication year - 2020
Publication title -
jphys materials
Language(s) - English
Resource type - Journals
ISSN - 2515-7639
DOI - 10.1088/2515-7639/ab7a02
Subject(s) - graphene , bilayer graphene , low energy electron microscopy , materials science , phase (matter) , dissipation , bilayer , atomic force microscopy , microscopy , epitaxy , nanotechnology , layer (electronics) , optics , chemistry , electron microscope , membrane , physics , biochemistry , organic chemistry , thermodynamics
Dynamic mode atomic force microscopy phase imaging is known to produce distinct contrast between graphene areas of different atomic thickness. But the intrinsic complexity of the processes controlling the tip motion and the phase angle shift excludes its use as an independent technique for a quantitative type of analysis. By investigating the relationship between the phase shift, the tip-surface interaction, and the thickness of the epitaxial graphene areas grown on silicon carbide, we shed light on the origin of such phase contrast, and on the complex energy dissipation processes underlying phase imaging. In particular, we study the behavior of phase shift and energy dissipation when imaging the interfacial buffer layer, single-layer, and bilayer graphene regions as a function of the tip-surface separation and the interaction forces. Finally, we compare these results with those obtained on differently-grown quasi free standing single- and bilayer graphene samples.