Electrodeposited Two-Layer Cu–In–Ga–Se/In–Se Thin Films

Cyclic voltammogram studies were performed on , , , and of and to understand the electrodeposition mechanism. The reduction potential from the cyclic voltammogram studies indicates that the first deposited layer is Cu from the Cu–In–Se and Cu–In–Ga–Se (CIGS) solution mixture. The subsequent deposition of the In and Ga layers is more favorable on the first deposited Cu layer. CIGS absorber layers were fabricated using a two-step electrodeposition process. The first layer of Cu-rich CIGS thin film was electrodeposited from , , , , and LiCl dissolved in a pH 3 buffer solution, and the subsequent second layer of the In–Se thin film was electrodeposited from a solution mixture of indium sulfate, sulfamic acid, and LiCl. The bilayer electrodeposited films were annealed in a vacuum chamber in Se atmosphere. The as-deposited and annealed films were analyzed by inductively coupled plasma spectrometry, scanning electron micrographs, and X-ray diffraction analysis.