Sulfurization of Cu/In precursors for CuInS2-based solar cells

The details of the sulfurization reaction of Cu/In metallic precursor layers for the preparation of CuInS2 photovoltaic absorbers have been investigated. For this, an experiment has been designed in order to establish the main mechanisms that govern the sulfurization reaction. A metallic layer containing Cu and In (Cu/In = 1.8) has been processed using a combined sequence of sulfurization and selenization steps. Afterwards, this sample was investigated by Auger electron spectroscopy, Raman spectroscopy, and transmission electron microscopy in order to study its microstructure and chemical composition. The results show that the sulfurization reaction of these films is dominated by the out-diffusion of the metallic atoms through the chalcogen layer. Moreover, taking into account our previous investigations we have developed a consistent model for the formation of these absorber layers. (C) 2003 The Electrochemical Society.