OPTICAL-PROPERTIES OF SPUTTER-DEPOSITED CERIUM OXYFLUORIDE THIN-FILMS

CeO(x)F(y) films were made by reactive rf magnetron sputtering of Ce i n Ar + O2 + CF4. Stoichiometries between CeO2 and CeO1.0F1.3 were obta ined when the CF4 content lay between 0% and 9%. For wavelengths lambd a of > 0.4 mum, the films were almost nonabsorbing, and the refractive index at lambda = 0.55 mum went from 2.32 for CeO2 to 1.62 at 9% CF4. At lambda < 0.4 mum and < 4% CF4, the optical properties were consist ent with an indirect band gap at 3.1-3.2 eV. CeO2 films could serve as intercalation hosts for Li+ ions.