Optical methods are of choice in a huge number of applications. In particular, those instruments based on vertical scanning methods provide extremely fast, non-contact characterization of surface topography. However some limitations are present. Among them, maximum detectable slope is limited (generally <30°). Local loss of signal, resulting from this limited detection, originates data files containing void pixels, which eventually provide poor surface characterization. This work presents an original approach to overcome instrumental limitation on the maximum detectable slope. The method presented here is based on a software tool that processes images taken with controlled tilt, and returns a high-quality 3D profile of the sample being investigated. Experimental evidence is given with reference to the case of a Vickers indentation on steel.

No abstract

No abstract

Titanium dioxide is rising growing interest because of its photocatalytic and photoelectrochemical properties. Under UV irradiation, photogenerated charge carriers can migrate to the surface and drive several redox reactions, from water splitting in hydrogen and oxygen to the photocatalytic decomposition of organic pollutants. Potential applications of TiO2 thin films range from self cleaning and superhydrophilic surfaces to photocatalytic air and water detoxification. One of the approaches to improve material performance involves transition metal doping of anatase thin films and colloids. The doping could affect not only the optical band gap, but also surface and morphology of nanocristalline thin films. In this work was explored the effect of Sn doping on anatase polycrystalline TiO2 films. Scanning Tunneling Microscopy (STM) was used to image the sample surfaces. Good STM images were obtained by TiO2 film deposition on conductive substrates (SnO2 coated glass). A statistical analysis of the roughness parameters from the images has been made, showing a correlation between photocatalytic activity and exposed surface area of the samples

No abstract