Quantification of phase content in TiO2 thin films by Raman spectroscopy

Recently, it has been reported that TiO2 with mixture of phases (anatase/rutile) exhibit higher photocatalytic activity than TiO2 with pure anatase phase. Therefore, the production and correct quantification of the ratio of phases becomes an important task. In this work, anatase TiO2 thin films were obtained by the DC reactive magnetron sputtering technique. TiO2 with mixture of phases (anatase/rutile) were prepared by thermal annealing of the as-deposited thin films. The value of the anatase/rutile ratio in the titanium dioxide thin films was estimated using Raman spectroscopy. Additionally, it is reported the dependence of the bandgap of the TiO2 thin films as a function of the anatase/rutile ratio. The band gap of the TiO2 thin films was determined from diffuse reflectance measurements

Ether gas-sensor based on Au nanoparticles-decorated ZnO microstructures

An ether gas-sensor was fabricated based on gold nanoparticles (Au-NPs) decorated zinc oxide microstructures (ZnO-MS). Scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM) measurements were performed to study morphological and structural properties, respectively, of the ZnO-MS. The gas sensing response was evaluated in a relatively low temperature regime, which ranged between 150 and 250 °C. Compared with a sensor fabricated from pure ZnO-MS, the sensor based on Au-NPs decorated ZnO-MS showed much better ether gas response at the highest working temperature. In fact, pure ZnO-MS based sensor only showed a weak sensitivity of about 25%. The improvement of the ether gas response for sensor fabricated with Au-NPs decorated ZnO-MS was attributed to the catalytic activity of the Au-NPs. Keywords: ZnO microstructures, Au nanoparticles, Ether, Gas senso