Numerical modeling and simulation help to optimize semiconductor devices such as solar cells in understanding key physi-cal phenomena and behaviors, thereby reducing time and cost. The development of solar energy engineering is progressed tremendously with the construction of integrated multi-junction solar cells based on III–V semiconductor compounds. In this study, an InGaP/GaAs double-junction solar cell is presented based on the back-surface field (BSF) layer. A unique and enhanced structure is created by introducing a 1.5-m-thick InAlGaP intrinsic material to the tunnel junction along with the introduction of the BSF top layer. In a single/multi-junction device, effective BSF is a crucial structural component for an efficient solar cell. Important parameters of open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), and efficiency (η) in the proposed solar cell model are calculated VOC = 2.7473 V, JSC = 1894.61 mA/cm2, FF = 87.544%, and η = 43.61%, respectively. The simulations are obtained at solar intensities (1000 suns) under the AM1.5G standard spectrum.
