Optical properties of CeO2 thin films

Abstract

Cerium oxide (CeO 2 ) thin films have been prepared by electron beam evaporation technique onto glass substrate at a pressure of about 6 × 10 -6 Torr. The thickness of CeO 2 films ranges from 140-180 nm. The optical properties of cerium oxide films are studied in the wavelength range of 200-850 nm. The film is highly transparent in the visible region. It is also observed that the film has low reflectance in the ultra-violet region. The optical band gap of the film is determined and is found to decrease with the increase of film thickness. The values of absorption coefficient, extinction coefficient, refractive index, dielectric constant, phase angle and loss angle have been calculated from the optical measurements. The X-ray diffraction of the film showed that the film is crystalline in nature. The crystallite size of CeO 2 films have been evaluated and found to be small. The experimental d-values of the film agreed closely with the standard values.

Cerium Dioxide Particles to Tune Radiopacity of Dental Adhesives: Microstructural and Physico-Chemical Evaluation

“…In this study, despite the decreased degree of conversion observed by increasing CeO2 addition, all groups showed values around 50%, which is in accordance with commercial dental adhesives [38]. Therefore, CeO2 = 2.2 to 2.8) [30], which may have decreased the accessibility of light energy inside the polymer. The limited mobility of monomer chains by the incorporation of the opaque fillers has also been considered as a contributing factor for the decrease in the monomer's conversion [31].…”

“…The outcome observed for the degree of conversion may be attributed to the high refractive index of CeO2 (approx. ղ = 2.2 to 2.8) [30], which may have decreased the accessibility of light energy inside the polymer. The limited mobility of monomer chains by the incorporation of the opaque fillers has also been considered as a contributing factor for the decrease in the monomer's conversion [31].…”

Enhanced photoelectrochemical activity of Ce doped ZnO nanocomposite thin films under visible light

“…But, the band gap of this oxide (3.6-3.8 eV) is higher than pure ZnO (3.37 eV). Thus, the band gap energy of Ce-ZnO film was measured greater than pure ZnO as also reported by others [34,35]. The variation of band gap energy with cerium concentration is shown in Fig.…”

Synthesis and Characterization of Nanostructured Cerium Dioxide Thin Films Deposited by Ultrasonic Spray Pyrolysis

“…C erium dioxide (CeO 2 ) has been of great interest during the last years due to its multiple applications in several key areas of thin film technology. This material has a cubic fluorite‐type crystal structure (lattice spacing 0.5411 nm) and combines a large bandgap (<3.5 eV) with a high dielectric constant (ɛ≈26), high ionic conductivity, and high‐temperature stability 1–8 . Because of its chemical stability and close lattice parameter matching with silicon (0.35% lattice matching), CeO 2 has potential applicability in the area of optoelectronics: in silicon‐on‐insulator structures, stable capacitor devices for large‐scale integration, photoelectrodes in dye‐sensitized solar cells, and stable buffer layers between high‐temperature superconducting materials and silicon substrates 6–14 .…”