XPS study on interface of oxygen sensing cerium dioxide/niobium pentoxide double-layer films

Oxygen sensitive double-layer CeO2/Nb2O5 films were grown on Al2O3 ceramic substrates by reactive RF/DC magnetron sputtering. The films were studied by XPS (X-ray photoelectron spectroscopy) to understand the interfacial diffusion after in-situ thermal annealing. The thermal diffusion of Nb2O5 into the top CeO2 layer results in that the trace doping of Nb2O5 into CeO2 layer can be realized, while the diffusion may promote the desorption of oxygen in the crystal lattice, so that CeO2 can be reduced to Ce2O3 more easily without variations in crystal structure and composition.