In this work, a heterogeneous thin flm solar cell with a FTO/TiO2/n-ZnSe/p-CdTe/Ag: ZnSe/Ni structure was designed and analyzed by using a SCAPS 1-D simulator program under AM 1.5 G illumination. In this confguration, FTO, TiO2, ZnSe, CdTe, and Ni act as the front electrode, the window layer, the bufer layer, the light-absorbing layer, and the back electrode, respectively. The Ag:ZnSe back surface feld (BSF) layer is used to decrease the barrier height in the valence band, limit recombination losses, and generate the necessary ohmic connection at the back contact of the ZnSe/CdTe cell. The efects of various bufer layers, variations in bandgap energy vs thickness, total defect density of the BSF layer, temperature, and metal work function were studied. The presence of the Ag: ZnSe BSF layer with a bandgap energy of 1.7 eV, thickness of 0.5 µm, and total defect density of 1014 cm−3 at 300 K increased the power conversion efciency from 17.01 to 22.31% when compared to the case where this layer was not present in the cell architecture
