Valence number transition and silicate formation of cerium oxide films on Si(100)

► The band alignment of Ce-silicate with respect to Si is determined by X-ray photoelectron spectroscopy. ► The photoelectron spectra of Ce3+, Ce4+ and Ce-silicates are extracted from Ce-oxide thin film on a Si wafer. ► The valence number change of Ce atoms after annealing was model base on reaction of Ce and Si substrate.