Thin-film technologies (aSi, CdTe, CIGS, GaAs)

Thin-film technologies are distinguished by the ability of materials to absorb sunlight at very low thicknesses, of the order of a few microns or less, as opposed to over a hundred or more for silicon. This is due to a difference in the electronic structure of the materials, enabling photons to be absorbed directly or indirectly. The consequence is a fundamental change in the preparation method, from cutting processes for silicon to coating processes for thin films, which can be carried out in vacuum, in atmosphere or in solution, and lead to a very significant improvement in manufacturing cost and production capacity.
In this lecture, we will present the thin-film processes that have reached industrial and commercial maturity (aSi, CdTe, CIGS), focusing on the spectacular developments in the physico-chemistry of materials and processes that have enabled them to become established, as well as the most recent developments in research and applications, in particular the quest for ultra-light, flexible and highly efficient photovoltaics.