Showing papers by "Nicola Bazzanella published in 2014"

Pulsed-laser deposition of nanostructured iron oxide catalysts for efficient water oxidation.

Abstract: Amorphous iron oxide nanoparticles were synthesized by pulsed-laser deposition (PLD) for functionalization of indium–tin oxide surfaces, resulting in electrodes capable of efficient catalysis in water oxidation. These electrodes, based on earth-abundant and nonhazardous iron metal, are able to sustain high current densities (up to 20 mA/cm2) at reasonably low applied potential (1.64 V at pH 11.8 vs reversible hydrogen electrode) for more than 1 h when employed as anodes for electrochemical water oxidation. The good catalytic performance proves the validity of PLD as a method to prepare nanostructured solid-state materials for catalysis, enabling control over critical properties such as surface coverage and morphology.

GeO2 glass ceramic planar waveguides fabricated by RF-sputtering

Abstract: GeO 2 transparent glass ceramic planar waveguides were fabricated by a RF-sputtering technique and then irradiated by a pulsed CO 2 laser. Different techniques like m-line, micro-Raman spectroscopy, atomic force microscopy, and positronbannihilation spectroscopy were employed to evaluate the effects of CO 2 laser processing on the optical and structuralbproperties of the waveguides. The GeO 2 planar waveguide after 2h of CO 2 laser irradiation exhibits an increase of 0.04 inbthe refractive index, measured at 1542 nm. Moreover, the technique of laser annealing is demonstrated to significantlybreduce propagation loss in GeO 2 planar waveguides due to the reduction of the scattering. Upon irradiation of the surfacebthe roughness decreases from 1.1 to 0.7 nm, as measured by AFM. Attenuation coefficients of 0.7 and 0.5 dB/cm at 1319 and 1542 nm, respectively, were measured after irradiation. Micro-Raman measurements evidence that the system embeds GeO 2 nanocrystals and their phase varies with the irradiation time. Moreover, positron annihilation spectroscopy was used to study the depth profiling of the as prepared and laser annealed samples. The obtained results yielded information on the structural changes produced after the irradiation process inside the waveguiding films of approximately 1 μm thickness.