Growth and Optical Properties of Cu(In, Ga)Se2 Thin Films on Flexible Metallic Foils

Polycrystalline Cu(In, Ga)Se2(CIGS) thin films on flexible metallic foils were prepared by two-stage selenization of sequentially deposited Cu, Ga and In precursors. The selenization procedure was carried at various recrystallization temperatures (T s) ranging from 230 to 520 °C. The phases, surface morphologies, microstructures and elemental depth profiles of the CIGS films prepared on different metallic flexible foils (titanium, molybdenum, stainless steel) were analyzed. Experiments show that the structural and optical properties of CIGS absorber layers strongly depend on the growth condition, type of substrate and chemical composition. The band gap energy (E g) of CIGS chalcopyrite compounds, grown on nontransparent flexible metallic substrates was estimated from the optical absorption data.