Atomic structure and electronic properties of Ce + O films co-adsorbed on Mo(112)

Abstract

The atomic structure, stoichiometry and electron work function of Ce + O films co-adsorbed on Mo(112) were studied by low-energy electron diffraction (LEED), Auger electron spectroscopy (AES) and contact potential difference (CPD) methods. The films with a significant predominance of one major species show the structure characteristic of the main component, which remains stable up to 15−50% of the minor species content. We report the c(4 × 4) and c(2 × 6) superstructures for Ce + O films with single layer Ce coverage as well as c(4 × 6) and (2 × 2) for double layer Ce coverage. They are exclusively specific to the (Ce + O)/Mo(112) system and have not been previously observed neither for cerium oxides nor pure cerium/pure oxygen adfilms. No noticeable electron work function change was detected due to oxygen addition to the Ce/Mo(112) films. Both oxygen-enriched and oxygen-depleted (Ce + O) films show similar typical electropositive properties.