NOVELTY - A system (40) comprises Group IB material electroplating station(s) to form Group IB material layer of metallic stack on surface of flexible foil that is advanced through Group IB material deposition station; Group IIIA material electroplating station(s) to form Group IIIA material layer of the metallic stack, while the Group IB material layer is continued to be electroplated onto surface portions of flexible foil in the Group IB material deposition station; and alloying furnace to transform the stack into alloy layer by intermixing the layers.    USE - For forming a precursor layer containing Group IB and Group IIIA materials for forming Group IB/IIIA/VIA compound absorber layer Group IB/IIIA/VIA compound absorber layer (claimed); useful for preparing thin films of semiconductors for photovoltaic/solar cell fabrication, and for radiation detector.    ADVANTAGE - The system forms high-quality, dense, well-adhering Group IB/IIIA/VIA compound thin films with macro-scale as well as micro-scale compositional uniformities at low-cost.    DETAILED DESCRIPTION - A system comprises: a Group IB material deposition station to electroplate a Group IB material layer of a metallic stack on surface portions of front surface of flexible foil that is advanced through Group IB material deposition station; Group IIIA material deposition station to electroplate a Group IIIA material to form a Group IIIA material layer of the metallic stack on the Group IB material layer as the flexible foil that is advanced through the Group IB material deposition station and the Group IIIA material deposition station and while the Group IB material layer is continued to be electroplated onto the surface portions of the flexible foil in the Group IB material deposition station; an alloying furnace to transform the metallic stack into an alloy layer by intermixing the layers of Group IB and Group IIIA materials; and another deposition station to electroplate Group IB material and/or Group IIIA material film onto the alloy layer. The metallic stack is continuously transformed into the alloy layer. The Group IIIA material is continued to be electroplated in the Group IIIA material deposition station on the Group IB material layer and while the Group IB material is continued to be electroplated onto the surface portions of the flexible foil in the Group IB material deposition station, thus obtaining precursor layer containing Group IB and Group IIIA materials. The system also comprises Group VIA material deposition station to electroplate Group VIA material on the Group IB, the Group IIIA material layer and/or the alloy layer, as the flexible foil is advanced, such that the Group VIA material deposition station is located after one of the Group IB material deposition station, the Group IIIA material deposition station, the alloying furnace, and the another deposition station, where the precursor layer contains Group IB, Group IIIA and Group VIA materials; and a reaction station to transform the precursor layer containing Group IB, Group IIIA and Group VIA materials into a Group IB/IIIA/VIA compound absorber layer by melting and intermixing.    DESCRIPTION OF DRAWING(S) - The figure shows schematic view of an apparatus for electroplating, cleaning and annealing thin layers.    Apparatus (40)    Substrate (40a)    Conductor (41)    Copper-gallium electroplating station (42a)    Electroplating cell (45)    Anode (47)    Inlet. (50)