Abstract: Thin films of copper indium gallium selenide Cu(In,Ga)Se2 (CIGS) were prepared by sequential elemental layer deposition in vacuum at room temperature. The as-deposited films were heated in vacuum for compound formation, and were studied at temperature as high as 1250℃ for the first time. These films were concurrently studied for their structural properties by X-ray diffraction (XRD) technique. The XRD analyses include phase transition studies, grain size variation and microstrain measurements with the reaction temperature and time. It has been observed that there are three distinct regions of variation in all these parameters. These regions belong to three temperature regimes: <450℃, 450–950℃, and >950℃. It is also seen that the compound formation starts at 250℃, with ternary phases appearing at 350℃ or above. Whereas, there is another phase shift at 950℃ without any preference to the quaternary compound.

Key words: Cu(In, Ga)Se2 (CIGS), X-ray Diffraction, Thin Films, Structural Analysis