Synthesis and Characterization of the CLS/CIGS Absorber Layer of Solar Cell using Metal Chloride Precursor Solution

Cu(In,Ga)Se-2 (CIS/CIGS) absorber films were economically synthesized using metal chloride (CuCl2, InCl3, GaCl3, and SeCl4) precursors in acetone solution with no addition of organic binders for doctor bladed deposition. Heat treatment was applied to CIS/CIGS precursors from 100 to 500 degrees C and the crystallinity and surface morphologies were investigated by FESEM, XRD, etc. It was observed that CIS crystals began to form at 300 degrees C and as the metal chloride concentration in the precursor solution became higher and the heat treatment temperature increased, then the CIS crystal size grew larger and the crystallinity was better. In addition, with the substitution of Ga for In, the (112) main peak in the CIS absorber layer shifted to a higher angle due to a decrease in the lattice parameter and its energy band gap increased. The best quality CIS film was obtained from a CIS concentration of 0.4 M / 0.4 M / 0.8 M with heat treatment of 500 degrees C for 30 minutes.