FORMATION OF THE CE Y2O3 INTERFACE - AN IN-SITU XPS STUDY/

We have studied the formation of the Ce/Y2O3 interface by X-ray photoe lectron spectroscopy (XPS) from a Ce vapor deposited onto a polycrysta lline stoichiometric Y2O3 sample. The substrate temperature ranged bet ween the room temperature and 850 degrees C, which is above the cerium melting point (795 degrees C). The shape of the Ce 3d photoelectron l ines shows that even at room temperature, an interfacial compound Ce2O 3-x forms over a few atomic layers. When the substrate temperature inc reases, the thickness of this oxidized layer increases. A model based on a diffusion mechanism of oxygen atoms coming from the oxide substra te is proposed to account for the experimental results.