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

TL;DR

This study uses angle-resolved photoemission spectroscopy to analyze the electronic structure of graphene on Ir(111), revealing how growth methods affect electronic properties and moiré superstructure features.

Contribution

It demonstrates that temperature programmed growth and chemical vapor deposition produce sharp electronic bands in graphene on Ir(111), and evaluates the system's electronic features and uniformity.

Findings

Graphene exhibits sharp electronic bands after specific growth methods.

Moiré superstructure features like minigaps and replica bands are identified.

Photon energy variation affects pi- and sigma-band intensities.

Abstract

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 pi-band is analyzed. Finally, by the variation of photon energy, relative changes of the pi- and sigma-band intensities are demonstrated.