Graphene on Ir(111) characterized by angle-resolved photoemission

Angle-resolved photoelectron spectroscopy (ARPES) is extensively used to characterize the dependence of the electronic structure of graphene on Ir(111) on the preparation process. ARPES findings reveal that temperature-programmed growth alone or in combination with chemical vapor deposition leads to graphene displaying sharp electronic bands. The photoemission intensity of the Dirac cone is monitored as a function of the increasing graphene area. Electronic features of the moir´e superstructure present in the system, namely, minigaps and replica bands are examined and used as robust features to evaluate graphene uniformity. The overall dispersion of the π band is analyzed. Finally, by the variation of photon energy, relative changes of the π and σ band intensities are demonstrated.