In situ growth of epitaxial cerium tungstate (100) thin films

The deposition of ceria on a preoxidized W(110) crystal at 870 K has been studied in situ by photoelectron spectroscopy and low-energy electron diffraction. Formation of an epitaxial layer of crystalline cerium tungstate Ce6WO12(100), with the metals in the Ce3+ and W6+ chemical states, has been observed. The interface between the tungsten substrate and the tungstate film consists of WO suboxide. At thicknesses above 0.89 nm, cerium dioxide grows on the surface of Ce6WO12, favoured by the limited diffusion of tungsten from the substrate.