| AVS 64th International Symposium & Exhibition | |
| Surface Science Division | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | Yujing Ma, University of South Florida |
| Authors: | Y. Ma, University of South Florida M. Batzill, University of South Florida |
| Correspondent: | Click to Email |
Ultrathin films of iron oxide form a two-dimensional (2D) FeO layer on Ir(111). Due to difference in lattice constant between 2D-FeO and Ir(111) a moiré superstructure is formed. We studied the 2D-FeO/Ir(111) structure by soft X-ray photoelectron spectroscopy(XPS), X-ray photoemission diffraction(XPD), and low energy electron diffraction(LEED), and scanning tunneling microscopy(STM). Moreover we show that this 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 attributed to 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.