Search

Abstract: Y2O3 thin film waveguides were prepared by RF magnetron sputtering. The effects of post-deposition annealing on the structure and optical properties have been investigated. The structural evolution of Y2O3 films with annealing temperature was investigated by X-ray diffraction (XRD). Spectroscopic ellipsometry was employed to determine the optical properties of Y2O3 films annealed at various temperatures. It was found that with increasing annealing temperature, the refractive index (n) of Y2O3 films increases. The optical band gap of Y2O3 films shifts to higher energy after higher temperature annealing, which is likely due to the reduction of defects and the change of crystalline structure in Y2O3 films. [Copyright &y& Elsevier]

Abstract: ZrO2 dielectric films were deposited on Si substrates by reactive magnetron sputtering technique. Interfacial and optical properties were investigated. Crystal structure was studied by X-ray diffraction. Fourier Transform Infrared Spectroscopy analysis confirmed the presence of a low-k interfacial SiO2 layer due to the excited oxygen radicals in the sputtering plasma and the physisorbed oxygen in as-deposited ZrO2 films. Optical constants were extracted based on the best spectroscopic ellipsometry fitting results. Absorption coefficients near the absorption edge were also calculated. The absorption tails in the range 4.5–4.75 eV indicated that there was a defect energy level below the conduction band of ZrO2 due to oxygen vacancies. [Copyright &y& Elsevier]

Abstract: Bulk-quantity GeO2 nanorods and nanotubes have been synthesized by simple thermal evaporation of metallic germanium powders. The nanorods and nanotubes have a diameter of about 100–150 nm and length of about 1 μm. Many of the nanotubes have a serrated out surface which is formed by twin crystals. The twin boundary can strengthen the mechanical property and increase the electrical resistance and thus vary the physical property of GeO2. The products can emit bright blue light with a peak at 448 nm under excitation at 381 nm at room temperature. So the products may have potential application in future integrated optical devices. [Copyright &y& Elsevier]

SnO2/SiO2 nanocomposite xerogel was synthesized by using the about-to-gel silica sol as “nanoglue”. Tin oxide uniformly dispersed within the three-dimension network of the silica in the form of nanoparticles. The SnO2/SiO2 nanocomposite xerogel has a large specific surface area (SSA), which depends on the deposition time of the silica sol. [Copyright &y& Elsevier]