Enhancing the Efficiency of In0.62Ga0.38N Solar Cells Using an InN Back Surface Field Layer: A Numerical Simulation Approach

Indium gallium nitride (InGaN) solar cells have emerged as promising candidates in photovoltaic research due to their tunable direct bandgap, strong light absorption, and favorable electronic characteristics. This study presents a numerical analysis of a p-InGaN/n-InGaN solar cell configuration, both with and without an added back surface field (BSF) layer, using the SILVACO-ATLAS 2D device simulation tool. The basic solar cell structure without a BSF layer (Al//p-InGaN/n-InGaN/Ag) serves as a reference, while a highly doped indium nitride (InN) BSF layer at the rear contact interface contact in the enhanced version. The study explores how variations in the BSF layer, in addition to the thickness and doping levels of the buffer and absorber layers, influence on key performance metrics such as open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), power conversion efficiency (PCE), and quantum efficiency (QE). Findings reveal that the introduction of the InN BSF layer improves the PCE from 23.52 to 24.43%, with a corresponding rise in JSC from 36.91 to 38.05 mA/cm², and VOC from 0.817 to 0.821 V. Furthermore, the quantum efficiency exceeds 78.32% over the 300–900 nm wavelength range. This work provides a comprehensive optimization approach and demonstrates that using an InN BSF layer can significantly enhance the efficiency of InGaN solar cells by mitigating recombination and improving carrier collection. The findings offer a pathway toward higher-efficiency InGaN-based solar cells, making this approach a promising candidate for future photovoltaic technologies in both terrestrial and space applications.