Patent ID: 7998789

Claim:
A method for forming a copper indium gallium sulfur selenide (CIGSSe) absorption layer and a cadmium sulfide (CdS) buffer layer, by which the CIGSSe absorption layer and the CdS buffer layer are sequentially formed on a back electrode layer on a substrate under non-vacuum conditions, comprising the following steps: a mixing process, mixing a CIGSSe powder, a solvent, and an additive to form a CIGSSe slurry; a coating layer forming process, coating the CIGSSe slurry on the back electrode layer to form a CIGSSe slurry coating layer, the coating layer forming process including one of a spray coating process, a coating process, and an immersing process; a drying process, pre-drying and removing the solvent in the CIGSSe slurry coating layer; a densification process, including a rolling process, a high-pressure liquid spray pressing process, and a high-pressure gas spray pressing process, in which a pressure is applied onto the CIGSSe slurry coating layer to densify the CIGSSe slurry coating layer; a primary selenization/sulfurization reaction process, comprising a primary sulfurization reaction and a primary selenization reaction by introducing hydrogen sulfide and hydrogen selenide, respectively, and making the CIGSSe slurry coating layer to produce sulfide and selenide by elevating temperature to form a primary CIGSSe absorption layer; a thermal process, carrying out a crystallizing process of the primary CIGSSe absorption layer; an impurity cleaning process, using an impurity scavenger to remove impurity compounds which are cuprous selenide and copper sulfide in the primary CIGSSe absorption layer, and carrying out cleaning and drying; a rear-stage selenization/sulfurization reaction process, comprising a rear-stage sulfurization reaction and a rear-stage selenization reaction which allow the primary CIGSSe absorption layer to further form a rear-stage CIGSSe absorption layer, through the rear-stage sulfurization reaction and the rear-stage selenization reaction; and a CdS buffer layer growth process, immersing the CIGSSe absorption layer in an aqueous solution comprising sulfur (S) and cadmium (Cd) so as to form the CdS buffer layer on the CIGSSe absorption layer by a chemical bath deposition method.