Growth and Surface Properties of Cuprous Oxide Films on Au(111)

Abstract

Reactive Cu deposition in an O2 ambience is used to prepare homogeneous copper oxide films on an Au(111) support. X-ray photoelectron spectroscopy reveals a predominant Cu2O stoichiometry of the ad-layers. Their growth morphology and atomic structure is determined with scanning tunneling microscopy (STM) and low-energy electron diffraction. The films grow in a layer-by-layer fashion and expose different terminations depending on the preparation conditions. While as-prepared films develop a variety of surface reconstructions, the structure of postannealed films is similar to the one of bulk-cut Cu2O(111). STM conductance spectroscopy is used to probe the local electronic structure and work function of the material. Apart from the ∼2.0 eV band gap of Cu2O, an unoccupied surface state is identified for annealed films. The high crystallographic quality of the cuprous oxide films renders them suitable for further investigations of the defect landscape and the optical properties of this reference material for p...