Temperature, a key environmental factor affecting photovoltaic devices, strongly influences the electrical performance of CIGS solar cells. This study examines cells with 30 and 60 nm CdS buffer layers using temperature-dependent current–voltage and capacitance–voltage (C–V) measurements. While both structures show similar efficiency temperature coefficients, the underlying recombination mechanisms differ: thin-buffer cells are dominated by interface-related processes, whereas standard-buffer cells exhibit more bulk-controlled behavior. C–V profiling indicates that thermally activated changes in carrier concentration shift with buffer thickness, occurring near the heterojunction in thin-buffer cells and deeper in the absorber for thicker layers. These spatial differences are consistent with thermally activated (VSe−VCu) defect transformations. Overall, temperature-dependent electrical characterization provides insight into dominant recombination pathways and reveals how buffer thickness influences the location and impact of thermally activated defect states in CIGS heterostructures.
Komilov et al. (Mon,) studied this question.