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 photocatalysis and photovoltaics.

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authorenWe present a temperature‐ and intensity‐dependent photoluminescence (PL) study of the binary semiconductor Bi2S3 on the mm‐scale and a laterally resolved PL measurement with a resolution of x≈900nm. The films can show a rather rough surface with needles and flakes of Bi2S3 with different orientations as well as very flat and smooth surface morphology. Despite a band gap of Eg≈1.3eV the films show a splitting of quasi‐Fermi levels (QFL) of μ≈700meV at room temperature. By means of temperature‐dependent PL we have located several radiative and non‐radiative defect states in the band gap. For a better understanding of this thin film semiconductor a full analysis of the laterally resolved PL measurement including the integrated PL yield, energetic position of the PL maximum, optical band gap, splitting of quasi‐Fermi levels and defect absorption of both sample morphologies is presented to avoid misinterpretation of experimental data.