Dependence of performance parameters of CdTe solar cells on semiconductor properties studied by using SCAPS-1D

• A device model of CdTe solar cells with an efficiency of 19.6% was developed.
• The improvement of Jsc resulted from the improved properties of CdS layers.
• The improvement of Voc and FF resulted from the decrease of defect density in CdTe films.
• Efficiency of 21% was achieved for CdTe films with low defect and high carrier densities.

A baseline model and an advanced model of CdTe solar cells with selected semiconductor properties fit to the performance parameters of the champion CdTe solar cells were developed. The responsible factors for the efficiency improvement of high-performance CdTe solar cell were analyzed. The thin CdS films, and the low defect densities and high carrier mobilities of the CdS films were the crucial factors for the enhancement of the short-circuit current density. With the suppression of carrier recombination, the open-circuit voltage and fill factor of the CdTe solar cells with the low defect densities in either CdTe films or interdiffusion layer were enhanced. In addition, the carrier collection was impeded for the interdiffusion layer with a high defect density, leading to the decrease of the short-circuit current density. Moreover, the simulation results revealed that the efficiency of 20–21% was achieved for the CdTe solar cells with the low defect densities and high carrier concentrations of CdTe films.