Performance Optimization of the InGaP/GaAs Dual-Junction Solar Cell Using SILVACO TCAD

Abstract

In this work, an optimization of the InGaP/GaAs dual-junction (DJ) solar cell performance is presented. Firstly, a design for the DJ solar cell based on the GaAs tunnel diode is provided. Secondly, the used device simulator is calibrated with recent experimental results of an InGaP/GaAs DJ solar cell. After that, the optimization of the DJ solar cell performance is carried out for two different materials of the top window layer, AlGaAs and AlGaInP. For AlGaAs, the optimization is carried out for the following: aluminum (Al) mole fraction, top window thickness, top base thickness, and bottom BSF doping and thickness. The electrical performance parameters of the optimized cell are extracted: $J_{\text{SC}}=18.23\text{mA}/\text{c}{\text{m}}^2$ , $V_{\text{OC}}=2.33\text{V}$ , $\text{FF}=86.42\%$ , and the conversion efficiency ( ${\eta }_{\text{c}}$ ) equals 36.71%. By using AlGaInP as a top cell window, the electrical performance parameters for the optimized cell are $J_{\text{SC}}=19.84\text{mA}/\text{c}{\text{m}}^2$ , $V_{\text{OC}}=2.32\text{V}$ , $\text{FF}=83.9\%$ , and ${\eta }_{\text{c}}=38.53\%$ . So, AlGaInP is found to be the optimum material for the InGaP/GaAs DJ cell top window layer as it gives 4% higher conversion efficiency under 1 sun of the standard AM1.5G solar spectrum at 300 K in comparison with recent literature results. All optimization steps and simulation results are carried out using the SLVACO TCAD tool.