NOVELTY - Forming semiconductor material on a substrate, comprises: forming a metal precursor film, where the step of forming the precursor film in a sequential order comprises forming (1302) a first layer above a surface of substrate, forming (1304) a second layer above the first layer, where the first and second layers comprise indium and copper or copper and indium, respectively, and forming a third layer (1306) above second layer, where the third layer comprises copper, and gallium and the third layer is formed using a sputtering process; and heating metal precursor film in presence of chalcogen.    USE - The method is useful for forming a semiconductor material on a substrate (claimed) which is useful for fabricating copper indium gallium selenide solar cells, where the substrates include float glass, low-iron glass, borosilicate glass, flexible glass, specialty glass for high temperature processing, stainless steel, carbon steel, aluminum, copper, titanium, molybdenum, polyimide, plastics and cladded metal foils.    ADVANTAGE - The method: provides copper indium gallium selenide absorber layers having a graded band-gap, in a simple and economic manner; and improves the performance of the device.    DETAILED DESCRIPTION - Forming a semiconductor material on a substrate, comprises: forming a metal precursor film, where the step of forming metal precursor film in a sequential order comprises forming (1302) a first layer above a surface of the substrate, forming (1304) a second layer above the first layer, where the first and second layers comprise indium and copper or copper and indium, respectively, and forming (1306) a third layer above the second layer, where the third layer comprises copper, and gallium, the third layer is formed using a sputtering process, and the sputtering process uses a sputtering target comprising 25-66 atomic% gallium; and heating the metal precursor film in the presence of a chalcogen at 100-700 degrees C.    DESCRIPTION OF DRAWING(S) - The figure illustrates a flow chart for a method used to form an absorber material.    Forming first layer (1302)    Forming second layer (1304)    Forming third layer (1306)    Fully converting the film into a chalcogenide film (1308)    Anneal the chalcogenide film (1310)