Ultrathin films of iron oxide form a two-dimensional (2D) FeO layer on Ir(111). Because of difference in lattice constant between 2D-FeO and Ir(111), a moiré superstructure is formed. The 2D-FeO/Ir(111) structure is examined by soft X-ray photoelectron spectroscopy, X-ray photoemission diffraction, scanning tunneling microscopy, and low-energy electron diffraction. A 2D-FeO layer may also be grown by iron intercalation and subsequent oxidation underneath a graphene layer on Ir(111). Thus, the graphene can be decoupled from the metal by the 2D-FeO layer. Changes in the graphene C 1s binding energy can be mainly explained by shifts in the Fermi level of graphene as a consequence of interface band alignment for weak interactions between graphene and the substrate. A shift of C 1s to lower binding energy, for graphene supported on FeO/Ir(111), is a consequence of the dipole moment in the 2D-FeO layer normal to the Ir(111) surface. Broadening of the C 1s peak is consistent with a locally varying 2D-FeO dipole within the moiré structure and thus implies a modulated charge doping of the graphene.
Titolo: | Periodic Modulation of Graphene by a 2D-FeO/Ir(111) Moiré Interlayer | |
Autori: | ||
Data di pubblicazione: | 2017 | |
Stato di pubblicazione: | Pubblicato | |
Rivista: | ||
Abstract: | Ultrathin films of iron oxide form a two-dimensional (2D) FeO layer on Ir(111). Because of difference in lattice constant between 2D-FeO and Ir(111), a moiré superstructure is formed. The 2D-FeO/Ir(111) structure is examined by soft X-ray photoelectron spectroscopy, X-ray photoemission diffraction, scanning tunneling microscopy, and low-energy electron diffraction. A 2D-FeO layer may also be grown by iron intercalation and subsequent oxidation underneath a graphene layer on Ir(111). Thus, the graphene can be decoupled from the metal by the 2D-FeO layer. Changes in the graphene C 1s binding energy can be mainly explained by shifts in the Fermi level of graphene as a consequence of interface band alignment for weak interactions between graphene and the substrate. A shift of C 1s to lower binding energy, for graphene supported on FeO/Ir(111), is a consequence of the dipole moment in the 2D-FeO layer normal to the Ir(111) surface. Broadening of the C 1s peak is consistent with a locally varying 2D-FeO dipole within the moiré structure and thus implies a modulated charge doping of the graphene. | |
Handle: | http://hdl.handle.net/11368/2895762 | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1021/acs.jpcc.6b11112 | |
URL: | http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.6b11112 | |
Appare nelle tipologie: | 1.1 Articolo in Rivista |
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