TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Composition: The substrate comprises glass, metal sheet or polyimide.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred composition: The barrier layer comprises compounds chosen from silicon nitride, silicon dioxide and silicon carbide. The back contact layer comprises refractory element chosen from molybdenum, tungsten, niobium, tantalum and rhenium. The sodium-doping source comprises sodium fluoride. The elemental layer comprises copper, indium, gallium and selenium. The sodium doping is achieved using elemental sodium derived from elemental sodium source. During sputtering process of copper-gallium from copper-gallium target, the ratio of copper and gallium is more than 1, and during sputtering of copper-indium from copper-indium target, the ratio of copper and indium is less than 1, during sputtering of copper-indium from copper-indium target, the ratio of copper and indium is less than 1, and during sputtering of copper-gallium from copper-gallium target , the ratio of copper and gallium is less than 1, and the ratio of copper with respect to total content of indium and gallium is 0.7-0.9, and the ratio of gallium with respect to total content of gallium and indium is 0-1. The source material comprises indium, gallium, selenium, sodium fluoride, sodium-doping source and/or elemental sodium, and further comprises portion of copper-indium-gallium powder. The carrier gas comprises nitrogen, argon, helium, neon and/or xenon. The heating tube of source material comprises molybdenum disilicide, silicon carbide, tantalum, graphitre, molybdenum, mullite and/or alumina. The conductive layer of solar cell apparatus comprises transparent conductive graphene. The solar cell layer (S1) comprises copper-indium-gallium-selenide, and crystalline silicon. The solar cell layer (S2) comprises copper-selenium-selenide (CuSeSe2), and amorphous silicon. The buffer layer (B1) and buffer layer (B2) cadmium sulfide and/or zinc sulfide. The solar cells are attached by mechanical connection using thin layer of transparent and conductive graphehe glue or transparent and conductive graphene oxide. The conductive layer comprises transparent conducting oxide. Preferred Properties: The thickness of the elements on the substrate formed by sputtering is 0.8-5 mu m. The solar cell layer (S1) has band gap less than 1 eV. The solar cell layer (S2) has band gap more than 1.5 eV.