Effects of Growth Temperature on the Morphological, Structural, and Electrical Properties of CIGS Thin Film for Use in Solar Cell Applications

Cu-In-Ga-Se nanoparticles (NPs) were synthesized using a colloidal route process. The effects of growth temperature (GT) on the properties of CuInGaSe2 (CIGS) thin films made from these nanoparticles were investigated using TEM, PL, XRD, and SEM techniques. The Cu-In-Ga-Se NPs were synthesized at growth temperatures ranging from 90 degrees C to 105 degrees C and then annealed at 550 degrees C for 7 min under a Se ambient. The resulting CIGS thin film, formed from Cu-In-Ga-Se NPs synthesized at a GT of 90 degrees C (referred to as GT90-CIGS), showed a tetragonal structure, large grain size, and high sunlight absorption. It had a band gap energy (Eg) of approximately 0.94 eV. Non-vacuum GT90-CIGS-based solar cells were investigated and fabricated using varying thicknesses of a CdS buffer layer. The maximum power conversion efficiency achieved was approximately 8.3% with an optimized device structure of Al/ITO/ZnO/CdS/CIGS/Mo.