Patent ID: 8741685

Claim:
A process for fabricating thin films of semiconductor I-III-VI 2 alloys that include sulfur, for photovoltaic applications, comprising: a) depositing a heterostructure comprising a thin film comprising elemental sulfur disposed on a thin precursor film on a substrate by: (i) depositing the thin precursor film of substantially amorphous or slightly crystalline I-III-VI 2 precursor, wherein the thin precursor film is deposited while mixing constituent elements of the precursor film such that the thin precursor film is deposited with a structure comprising nanograins of alloys joined together by amorphous phases, and (ii) depositing the thin film comprising elemental sulfur on the thin precursor film; and b) annealing the heterostructure to favor diffusion of the sulfur into the thin precursor film and at least partial crystallization of the I-III-VI 2 alloy of the precursor film with a stoichiometry thus including sulfur, wherein the sulfur at least partially replaces the element VI of the I-III-VI 2 precursor, and wherein the proportion of sulfur in the I-III-VI 2 alloy obtained in step b) is controlled at least according to a relative thickness of the thin film comprising elemental sulfur.