Optical properties of spin coated CeO2-TiO2-ZrO2 thin films

Complete text of publication follows. Ternary thin films of cerium titanium zirconium mixed oxide were prepared by the sol-gel process and deposited by a spin coating technique at different spin speeds (1000-4000 rpm). Ceric ammonium nitrate, Ce(NO3)6(NH4)2, titanium butoxide, Ti[O(CH2)3CH3]4, and zirconium propoxide, Zr(OCH2CH2CH3)4, were used as starting materials. For molecular, structural and morphological characterization of the films, FTIR spectral analysis, X-ray diffraction (XRD), and atomic force microscopy (AFM) were carried out. All the ternary oxide thin films were amorphous. Optical constants (refractive index, extinction coefficient, band gap) and thickness of the films were determined in the 350-1000 nm wavelength range by using an nkd spectrophotometer. The refractive index, extinction coefficient, and thickness of the films were changed by varying the spin speed. The optical band gap is independent of the spin speed and has a value of about Eg ∼ 2.82 ± 0.02 eV for indirect transition.