NOVELTY - Fabricating a thin film photovoltaic solar energy collector film involves: providing substrates (208); transferring substrates into a furnace; introducing selenide species and carrier gas into furnace and transferring thermal energy into furnace to increase first temperature to second temperature; maintaining second temperature for a period of time; removing residual selenide species from furnace; introducing a sulfide species into furnace; and increasing third temperature of 500-525 degrees C while substrates are maintained to extract out selenium species from copper indium di-selenide film.    USE - For fabricating thin film photovoltaic solar energy collector film (claimed); and for making copper indium diselenide (CIS)-based and/or copper indium gallium diselenide species (CIGS)-based solar cells on a large glass substrate for a solar panel.    ADVANTAGE - The process are compatible with conventional systems, which allow cost effective implementation. The temperature control method maintains structure integrity of substrates while allows various reactions to occur. The method is a cost-effective method for making thin film solar cell panel; and maintains structure integrity of substrate materials, ensures uniformity and granularity of the thin film material.    DETAILED DESCRIPTION - Fabricating a thin film photovoltaic solar energy collector film involves: providing several substrates (208), where each of the substrate have a copper and indium composite structure; transferring the several substrates into a furnace, each of the several substrates provided in a vertical orientation with respect to a direction of gravity, the several substrates are defined by a number N (where N is greater than 5); introducing a gaseous species including a selenide species and a carrier gas into the furnace and transferring thermal energy into the furnace to increase a temperature from a first temperature to a second temperature, the second temperature is 350-450 degrees C to at least initiate formation of a copper indium di-selenide film from the copper and indium composite structure (200) on each of the substrates; maintaining the temperature at about the second temperature for a period of time; removing at least residual selenide species from the furnace; introducing a sulfide species into the furnace; and increasing a temperature to a third temperature, where the third temperature is 500-525 degrees C while the several substrates are maintained in an environment including a sulfur species to extract out at least one selenium species from the copper indium di-selenide film; where the removing of residual selenide species from the furnace occurs until the furnace is in a vacuum configuration, the vacuum is less than 1%.    DESCRIPTION OF DRAWING(S) - The figure shows a simplified diagram of a composite structure including a copper and indium film.    Structure (200)    Indium layer (202)    Copper layer (204)    Metal layer (206)    Substrate (208)