Exploring photovoltaic potential of group IV ternary Si1-x-yGeySnx alloys in solar cells: An in-depth numerical Analysis

Group IV compound semiconductors consisting of silicon (Si), germanium (Ge), and tin (Sn) based Si_1-x-yGe_ySn_x alloys are promising materials for next-generation photovoltaic (PV) applications because of their tunable bandgap and compatibility with existing Si technology. These materials are the backbone for the emerging field of Si Photonics as well. This study systematically explores the PV performance of Si_1-x-yGe_ySn_x -based solar cells by varying the Ge composition (y = 0.25, 0.30, 0.35, 0.40). The structure incorporates WS₂ as an electron transport layer (ETL) and Cu₂O as a hole transport layer (HTL). The simulation for investigating the performance of Cu₂O/Si_1-x-yGe_ySn_x/WS₂/FTO solar cell structures provides insights into key performance by optimizing the absorber layer Si_1-x-yGe_ySn_x composition, absorber and transport layer thicknesses, absorber layer defect density, and interface defect density, etc. The optimized device resulted in a conversion efficiency of 24.45 % at 0.25 of Ge composition in Si_1-x-yGe_ySn_x, Open-circuit voltage (V_OC) of 0.97 V, Short-circuit current density (J_SC) of 28.93 mA/cm², Fill factor (FF) of 86.94 %. The findings provide insights into optimizing Group IV Si_1-x-yGe_ySn_x -based solar cells and to the best of the knowledge of the authors, this is the first attempt to work on advanced numerical simulation on group IV ternary alloy-based solar cell structures. The results reported in this study may pave the way for the development of advanced high-efficiency group IV alloy-based solar cells in the future.