HIM-SIMS imaging of fluorinated polycrystalline graphene on copper

Auteurs

Selfors E.W., Flatabø R., Audinot J.N., Parsons D.F., Holst B.

Référence

Surfaces and Interfaces, vol. 55, art. no. 105337, 2024

Description

Fluorinated graphene is a fluorocarbon derivate of graphene. It is known as the two-dimensional counterpart of Teflon. The fluorine coverage on the graphene surface depends on the supporting substrate, the fluorination reaction itself and the final state after the finished reaction. The spatial distribution of fluorine atoms is debated, especially the reactivity of defects in the graphene layer and the resulting increase or decrease in fluorine concentrations in these regions. Here we use a novel detection system, a secondary-ion-mass spectrometer coupled to a helium/neon ion microscope. The technique allows for direct mapping of the spatial distribution of fluorine, and we present the highest-resolution fluorinated graphene distribution. We show that fluorine is uniformly distributed on polycrystalline graphene on copper foil. Hotspots of fluorine are found in regions identified as adlayers. Longer carbon features, grain boundaries or wrinkles, show no increased or decreased fluorine content, contrasting with the notion of changed reactivity at line defects. These measurements are corroborated by density functional theory calculations which shows barely any preference for the adsorption of XeF2 on grain boundaries.

Lien

doi:10.1016/j.surfin.2024.105337