Patent ID: 8198122

Claim:
A method for forming a thin film photovoltaic device comprising: providing a substrate comprising a surface region; forming a first electrode layer overlying the surface region; forming a copper layer overlying the first electrode layer; forming an indium layer overlying the copper layer to form a multi-layered structure; subjecting at least the multi-layered structure to a thermal treatment process in an environment containing a sulfur bearing species; forming a bulk copper indium disulfide material from the multi-layered structure, wherein the bulk copper indium disulfide material comprises a surface region characterized by a copper poor surface; subjecting the copper poor surface and one or more portions of the bulk copper indium disulfide material to chloride species; converting the copper poor surface from an n-type characteristic to a p-type characteristic; converting any of the one or more portions of the bulk copper indium disulfide material from a n-type characteristic to an p-type characteristic; forming a window layer overlying the bulk copper indium disulfide material.