Nanoscale morphology and fractal analysis of TiO coatings on ITO substrate by electrodeposition.

In this paper, we introduced an advanced discussion of the 3D morphology of TiO coatings deposited on ITO substrate by electrodeposition under different deposition times. Atomic force microscopy was applied for obtaining topographic images of the samples. The images were processed using the MountainsMap 8.0 commercial software according to ISO 25178-2:2012. Moreover, fractal theory was applied to study the surface microtexture of coatings. The morphology was affected by the deposition time, where the grain size decreased with the increase of the time, making film's surfaces smoother. In addition, the surface roughness exhibited a random behaviour, but does not presented significant difference between samples. The fractal dimension showed similar values for all coatings. In contrast, surface texture isotropy also exhibited random behaviour. However, advanced fractal parameters revealed that when the deposition time increased, the coatings microtexture has become uniform and less porous. Furthermore, all coatings presented high topographic uniformity, regardless of deposition time. These results revealed that the morphology and microtexture of TiO -based coatings can be controlled by the deposition time. LAY DESCRIPTION: An advanced characterization on the micromorphology of 3D morphology, using AFM images, of Titanium dioxide (TiO ) coatings deposited on ITO substrate by electrodeposition under different deposition times. TiO is one of the most studied semiconductors to make photovoltaic devices. The versatility of this semiconductor is associated with low toxicity, high photochemical stability, abundance, and the facility to obtain by conventional synthesis routes. The obtention of a homogeneous and stable layer in the semiconductor TiO film deposition is a crucial stage in the assembly of sensitized photovoltaic devices. Atomic Force Microscopy (AFM) is a technique which can magnify up to a billion times and it uses a tip or probe which touches the sample surface point by point. The tip deflection is interpreted as the surface topography by the software, producing 2D or 3D images that generate several tribological parameters such as roughness in respect to a scanned area, has been a technique widely reported in the morphological characterization, determination of thickness, roughness, and particle size in thin films. Therefore, in this paper, the morphology was studied by atomic force microscopy using MountainsMap commercial software. The main goal was to study the influence of the deposition time on the morphology and microtexture of the material. New parameters such as surface entropy, fractal succolarity and fractal lacunarity were obtained for studying coatings microtexture's complexity.