CuInGaSe2 (CIGS) thin film on flexible Mo substrates from non-aqueous one-step electrodeposition process

CuInGaSe2 (CIGS) thin films have been potentiostatically electrodeposited from the non-aqueous electrolyte bath at 130 °C onto flexible molybdenum foil. The deposition potential for the quaternary CIGS layer was optimized using cyclic voltammetry measurements. The samples were electrodeposited at − 0.8 and − 1.1 V with respect to the Ag/AgCl reference electrode and subsequently annealed with rapid thermal processing. The samples were characterized for the structural, optical morphological, and compositional properties using a range of characterization techniques. RTP annealed samples show a significant improvement in crystallinity and particle size. XRD results revealed the three prominent reflections of chalcopyrite CIGS corresponds to (112), (204)/(220), and (116)/(312) reflection of a tetragonal crystal structure. The prominent peak exhibit in Raman spectra at 174 cm−1 corresponds to the A1 mode symmetry of the CIGS chalcopyrite phase. The optical energy band gap is estimated to be ~ 1.12 and 1.35 eV for annealed samples deposited at − 0.8 V and − 1.1 V, respectively. SEM images confirmed the growth of uniform void-free and densely packed thin layer suitable for the CIGS thin-film solar cell. Electrical studies show the improvement in the ideality factor and carrier concentration in the RTP annealed samples. It was further found that the deposition potential plays an important role to control the stoichiometry and uniformity of the samples.