Simulation Modeling and Performance Optimization of CdS/CdTe Thin-Film Solar Cells

Cadmium telluride (CdTe) is a direct-bandgap semiconductor with strong optical absorption and is therefore well suited to thin-film photovoltaic conversion. This study brings together the AFORS-HET modeling work on CdS/CdTe devices, the figures and material-parameter table, and supporting literature supplied with the project. The analysis focuses on three closely connected limitations: the formation of a non-ohmic Schottky barrier at the metal back contact, the use of a highly doped electron-reflector (ER) region to modify carrier transport near that contact, and surface recombination velocity as an effective model for pinhole- or defect-related losses. The simulations indicate that back-contact and interface conditions influence open-circuit voltage much more strongly than short-circuit current density. An optimized modeled structure using an ER, a doping concentration of 7 × 1018 cm−3, an ER thickness of 100 nm, and an effective barrier height of approximately 0.1 eV reaches a simulated efficiency of 19.83%, with Voc = 917.6 mV and Jsc = 28.45 mA/cm2. The surface-recombination study further shows that severe pinhole conditions can lower Voc to approximately 0.73 V. These results are interpreted together with literature on CdTe doping, interface engineering, minority-carrier lifetime, grain-boundary recombination, and Cu-related back-contact effects.The combined picture emphasizes that high optical absorption alone is not sufficient: contact selectivity, interface quality, carrier lifetime, and defect control must be optimized simultaneously.