Deposition potential-driven growth and characterization of electrodeposited CIGS thin films for photovoltaic applications
摘要
Copper indium gallium selenide (CIGS) thin films, renowned for their high efficiency in photovoltaic applications, were synthesized via an environmentally benign and cost-effective electrodeposition technique. Cyclic voltammetry (CV) was utilized to identify the optimal deposition potential, while chronoamperometry provided insights into the nucleation mechanism of the CIGS layers. The as-deposited films underwent selenization through Rapid Thermal Processing (RTP), resulting in highly crystalline CIGS layers with preferred orientation along the (112) plane. Films deposited at a cathodic potential of –0.9 V exhibited a single-phase chalcopyrite structure, with no detectable secondary phases. At more negative deposition potentials, Cu-rich CIGS layers with p-type conductivity were formed, along with the presence of secondary binary Cu–Se phases. Conversely, films deposited at higher cathodic potentials demonstrated enhanced incorporation of (In + Ga) species. Field emission scanning electron microscopy (FESEM) confirmed that all deposited CIGS layers were compact and uniformly distributed across the substrate. The optical bandgap and conductivity type were further validated through optical absorption and photoelectrochemical measurements. These results underscore the influence of deposition potential on phase purity, crystallinity, and stoichiometry, providing a pathway toward scalable fabrication of high-quality CIGS thin films for solar energy applications.