Comparative analysis of GaAs solar cells performance using different FSF and BSF material sets

This study aims to analyze the impact of varying the front surface field (FSF) and back surface field (BSF) materials using Al0.8Ga0.2As, (Al0.7Ga0.3)0.5In0.5P, and In0.49Ga0.51P in pairs on single-junction GaAs solar cells performance with the aid of the SILVACO simulator. The solar cells with different FSF and BSF material sets are compared based on the photogeneration, recombination, and energy band structure. The results show that the initial cell without FSF and BSF gives an efficiency of 11.42%. When AlGaAs is used as the FSF layer the efficiency is significantly enhanced to 25.65%, 25.72%, and 30.16% as AlGaAs, InGaP, and AlGaInP are used for the BSF layer, respectively. When InGaP is utilized as the FSF layer, the efficiency also increases to 24.05%, 24.12%, and 27.94% as AlGaAs, InGaP, and AlGaInP are served as the BSF layer, respectively. The efficiency enhancement when AlGaAs and InGaP are used as the FSF is correlated to their high energy bandgap that enhances the photogeneration rate and smoothens the flow of photogenerated electrons toward the back contact. The extreme performance of the cells with AlGaInP BSF is attributed to the high potential barrier for the valance band between the base and BSF layer, which enhances the ability to confine the photogenerated holes in the solar cell and smoothen their flow toward the front contact. While using AlGaInP as the FSF layer, the cells' efficiency is degraded to about 6% regardless of the BSF material, which is due to the high potential barrier height for the conduction band between FSF and emitter and the low potential step between the emitter and base leading to a higher recombination rate for photogenerated electrons within the emitter. Based on this study, the best FSF and BSF materials set to obtain an optimum GaAs solar cell performance are AlGaAs and AlGaInP, respectively.