## 4 Conclusions  
The study presented in this paper explores the modeling and optimization of a \(InGaP/GaAs\) tandem solar cell incorporating an \(AlGaAs/AlGaInP\) tunnel junction using  
Figure 15: I–V curve of the optimized \(InGaP/GaAs\) DjSCs.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Solar Cell** & **Sun** & \(\mathbf{J_{SC}}\) **(mA/cm2)** & \(\mathbf{V_{OC}}\) **(V)** & **FF (\%)** & \(\mathbf{\eta}\) **(\%)** \\ \hline \hline
**Ourstudy** & **1** & **21.65** & **2.319** & **84.001** & **41.585** \\ \hline Experimental [4] & 1 & 16.1 & 2.39 & 87.52 & 32.19 \\ InGaP/GaAs [5] & 1 & 17.41 & 2.45 & 88.70 & 36.24 \\ InGaP/GaAs [6] & 1000 & 18.2 & 2.66 & 88.29 & 40.87 \\ InGaP/GaAs DjSCs [44] & 1 & 16.13 & 2.45 & 88.8 & 35.15 \\ Perovskite/perovskite [45] & 1 & 16.72 & 2.20 & 81.8 & 30.1 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Parameters of the different optimized \(InGaP/GaAs\) DjSCs structures compared to the developed design.  
Silvaco-Atlas software in the main aim to enhance its performance. The optimization process carried out in this paper has focused on two critical design parameters, such as the doping concentration of the lower buffer layer and the thickness of the upper BSF double layer. Indeed, based on precise adjustments of these two parameters, significant improvements have been achieved in the performance of the \(InGaP/GaAs\) (DJSCs) solar cells. The accurate investigation that has been performed allows identifying the buffer layer and the multilayer BSF top layer as key factors influencing the efficiency of the \(InGaP/GaAs\) tandem solar cells. Indeed, the achieved optimization has led to the determination of the optimal doping concentration for the bottom cell buffer layer, which is 1 \(\times\) 10\({}^{19}\) cm\({}^{-3}\), and the ideal thickness of the BSF double layer, which is 0.12 \(\upmu\)m. Under these optimized values, the device achieved a short-circuit current density (\(Jsc\)) of 21.65 mA/cm\({}^{2}\), an open-circuit voltage (\(Voc\)) of 2.319 V, a fill factor (\(FF\)) of 84.001%, and a conversion efficiency (\(\eta\)) of 41.585%. These outstanding results highlight the high accuracy and efficiency of the developed and simulated model, surpassing previously reported performance values in various previously published papers. It is expected from the present study to be expanded to other enhanced structures based on multi-junction structures and various anti-reflective coatings. Furthermore, the presented study is intended to be validated through experimental investigation in a specialized laboratory.  
Conceptualization, I.Z. and Z.B.; methodology, I.Z., Z.B., N.H., A.K. and A.H.; software, I.Z. and Z.B.; validation, I.Z., Z.B., N.H., A.K. and A.H.; formal analysis, I.Z., Z.B. and N.H.; investigation, I.Z., Z.B. and Z.B.; resources, I.Z. and Z.B.; data curation, I.Z., Z.B., N.H., A.K. and A.H.; writing--original draft preparation, I.Z., Z.B., N.H., A.K. and A.H.; writing--review and editing, A.K., A.H. and M.A.; visualization, I.Z., Z.B., A.K., M.A. and J.R.; supervision, Z.B., N.H., A.K., A.H. and M.A.; project administration, A.K., M.A. and J.R.; funding acquisition, M.A. and J.R. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. Not applicable. Not applicable. Data Availability Statement: All data used in this study are provided within the paper and its referenced sources. [PERSON] acknowledges the support provided by ANID through projects FB0008, 1210208, and 1221293. The authors declare no conflicts of interest.