Reversible graphene decoupling by NaCl photo-dissociation

We describe the reversible intercalation of Na under graphene on Ir(1 1 1) by photo-dissociation of a previously adsorbed NaCl overlayer. After room temperature evaporation, NaCl adsorbs on top of graphene forming a bilayer. With a combination of electron diffraction and photoemission techniques we...

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Bibliographic Details
Published in:2d materials 2019-02, Vol.6 (2), p.25021
Main Authors: Palacio, I, Aballe, L, Foerster, M, de Oteyza, D G, García-Hernández, M, Martín-Gago, J A
Format: Article
Language:English
Subjects:
alkali metals
decoupling
graphene
intercalation
NaCl
photo-dissociation
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Summary:We describe the reversible intercalation of Na under graphene on Ir(1 1 1) by photo-dissociation of a previously adsorbed NaCl overlayer. After room temperature evaporation, NaCl adsorbs on top of graphene forming a bilayer. With a combination of electron diffraction and photoemission techniques we demonstrate that the NaCl overlayer dissociates upon a short exposure to an x-ray beam. As a result, chlorine desorbs while sodium intercalates under the graphene, inducing an electronic decoupling from the underlying metal. Low energy electron diffraction shows the disappearance of the moiré pattern when Na intercalates between graphene and iridium. Analysis of the Na 2p core-level by x-ray photoelectron spectroscopy shows a chemical change from NaCl to metallic buried Na at the graphene/Ir interface. The intercalation-decoupling process leads to a n-doped graphene due to the charge transfer from the Na, as revealed by constant energy angle resolved x-ray photoemission maps. Moreover, the process is reversible by a mild annealing of the samples without damaging the graphene.
ISSN:2053-1583
2053-1583
DOI:10.1088/2053-1583/ab056e