Physical, chemical and electrochemical properties of pure and doped ceria

Variable angle spectroscopic ellipsometry (VASE) has been used in the photon energy range 125–50 eV to study the structure and optical properties of cerium dioxide (CeO2) films Both amorphous and highly oriented crystalline films were grown on sapphire by rf magnetron sputtering The crystallinity, chemical structure, and surface morphology of the films were studied by x‐ray diffraction, x‐ray photoelectron spectroscopy, and atomic force microscopy, respectively The measured VASE spectra on a series of films with different thicknesses were analyzed by using multiple optical models In this way, the complex refractive index N=n+ik of CeO2, the film thicknesses, and the surface roughness of the different films could be determined The ellipsometrically deduced refractive index spectrum was observed to be strongly dependent on the film structure Highly oriented crystalline CeO2 films exhibited a higher refractive index and a higher band gap energy than the amorphous film The surface roughness of the cr

A spectroscopic ellipsometry study of cerium dioxide thin films grown on sapphire by rf magnetron sputtering

Growth of cerium(IV) oxide films by the electrochemical generation of base method

Room-temperature (20° C) epitaxy of high-melting point CeO2 thin films was achieved for the first time on Si(111) substrates. Cross-sectional high-resolution transmission electron microscopy, Rutherford backscattering spectrometry and ion scattering spectroscopy confirmed the formation of a sharp oxide/silicon heterointerface with no boundary amorphous layer and single crystallinity of the present CeO2 films. This was achieved by pulsed laser deposition in an ultrahigh vacuum under optimized oxygen partial pressures and by hydrogen termination of the Si surface.

https://iopscience.iop.org/article/10.1143/JJAP.34.L688/pdf

Room-Temperature Epitaxial Growth of CeO2 Thin Films on Si(111) Substrates for Fabrication of Sharp Oxide/Silicon Interface

The nanocrystalline cerium dioxide (CeO2) thin films were deposited on soda lime (SLG) and Corning glass by pulsed e-beam deposition (PED) method at room temperature. The structure of the produced CeO2 thin films was investigated by X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and micro Raman spectroscopy. The surface topography of the films was examined by atomic force microscopy (AFM). Film thickness and growth morphologies were determined with FEG-SEM from the fracture cross sections. XPS studies gave a film composition composed of +4 and +3 valent cerium typical to nanocrystalline ceria structures deficient in oxygen. The ceria films were polycrystalline in nature with a lattice parameter (a) of 0.542 nm. The Raman characteristics of the source material and the films deposited were very similar in character. Raman lines for thin film and bulk CeO2 was observed at 465 cm−1. The optical properties of the CeO2 films were deduced from reflectance and transmittance measurements at room temperature. From the optical model, the refractive index was determined as 1.8–2.7 in the photon energy interval from 3.5 to 1.25 eV. The optical indirect band gap (Eg) of CeO2 nanocrystalline films was calculated as 2.58 eV.

G. Mages

Papers

Properties of CeO2 and CeO2−x films Part II. High temperature properties

Properties of CeO2 and CeO2−x films Part I. Preparation and crystallographic properties