This thesis deals with an experimental and theoretical study of micro-structured silicon surfaces, obtained by processing in SF6/02 plasma at cryogenic temperatures. Texturing which results from this treatment gives remarkable properties to these surfaces. One of them is the ability to trap and absorb light, resulting in a black color of the surface, hence the name of Black Silicon. This property that we find in the visible and near infrared spectral ranges, is of particular interest for solar energy conversion, both through photovoltaic and photo-thermal means. The study that we conducted, however, covered a much wider spectral range, extending to the Terahertz. For this purpose, different spectral characterization techniques have been implemented. Analysis of the results was also done using electromagnetic simulations. Correlations were found between the optical and morphological characteristics of micro-structured surfaces. The analysis of images taken by electron microscopy allowed sketching a theory attempting to explain the mechanism of formation of the microstructures of Black Silicon. Finally, a micro-component has been fabricated towards implementing the first part of this application work. It is a photo-thermal conversion device that incorporates platinum thermo-resistance on a surface of Black Silicon, realized on a thermally insulated Silicon membrane
