In order to improve the solar cell efficiency, quantum multi-wells have been implanted into the intrinsic region of the structure. We can absorb the photons that have a lower energy than the bandgap energy. In this work, physical and optical phenomena that influence the efficiency of the solar cell have been modeled, simulated and optimized. In addition, the effects of indium (x) and nitrogen (N) concentrations, the quantum wells number (nQWs) and the quantum well width (Lw) on structural stability, bandgap energy, external quantum efficiency and the solar cell output parameters were studied. For indium and nitrogen concentrations x = 35%, y = 3.5% respectively, a quantum well width LW = 8 nm and quantum wells number nQWs of 50, we have obtained a strain (ε) of about 1.77%. The obtained external quantum efficiency (EQE) in this case is about 86.23%, while the efficiency (η) is 33.60%. We can improve this work by using other materials.