NOVELTY - Substrate(s) (200) has surface, on which oxide material (210) is provided, and metallic electrode material (220) or dielectric material, is formed by sputter depositing molybdenum material. Deposition is performed by forming precursor material (231) comprising copper-gallium species, precursor material (232) comprising copper-gallium species, and precursor material (233) comprising indium material. Precursor materials (231, 232 and/or 233) are processed in environment comprising selenium species to form absorber material comprising sodium species, copper, and indium-gallium species.    USE - Method of processing sodium doping for thin-film photovoltaic material used for making solar cell.    ADVANTAGE - The method provides high-efficiency thin-film photovoltaic material.    DETAILED DESCRIPTION - Substrate(s) (preferably, soda lime glass substrate), has surface, on which oxide material (preferably, silicon oxide or titanium oxide) as diffusion barrier, or a dielectric material is provided, and metallic electrode material is formed over oxide material or dielectric material, preferably by sputter depositing bi-layer molybdenum material. Sputter deposition process is performed using target device (A) comprising sodium species, copper species and gallium species to form precursor material (231) comprising copper-gallium species having copper-gallium composition ratio (A1), precursor material (232) comprising copper species and gallium species is deposited by target device (B) having copper-gallium composition ratio (B1) similar to copper-gallium composition ratio (A1), and formed over precursor material (231), and precursor material (233) comprising indium material is formed over precursor material (232). Precursor materials (231, 232 and/or 233) are subjected to thermal treatment(s) (300) in environment comprising selenium species (preferably, gaseous selenium species) to form absorber material comprising sodium species and copper, and indium-gallium species. The atomic ratio of copper and indium-gallium species is 0.9 or less. An INDEPENDENT CLAIM is included for structure for forming photovoltaic material.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view explaining the method of processing sodium doping for thin-film photovoltaic material.    Substrate (200)    Oxide material (210)    Metallic electrode material (220)    Precursor materials (231,232,233)    Thermal treatment (300)