Stabilization of the ceria i-phase (Ce7O12) surface on Si(111)

In this work a 250 nm CeO2(111) film grown on a hex-Pr2O3(0001)/Si(111) system is annealed at 660 degrees C for 30 min to form the i bulk phase of Ce7O12 as controlled by x-ray photoelectron spectroscopy. The (111) surface of the stabilized i phase is characterized via high-resolution low-energy electron diffraction. The i-phase surface exhibits a (root 7 x root 7)R19.1 degrees superstructure with two mirror domains. This structure is attributed to a periodic ordering of oxygen vacancies compared to the fluorite structure of CeO2. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795867]