Simulation and analysis of p-ZnSiP2/n-Si heterojunction solar cells

ZnSiP2, a wide band gap, ternary III-V analog with 0.59/0 lattice mismatch with Si, has the potential to implement a monolithic top cell on silicon for higher photoelectric conversion efficiency tandem photovoltaics due to reduced thermalization losses. In this paper, The influence of thickness, doping concentration and minority carrier lifetime of ZnSiP2 layers on the performance of p-ZnSiP2/n-Si heterojunction solar cells are investigated by two-dimensional simulation software Silvaco TCAD Atlas. The simulation results indicate that the short circuit current, open circuit voltage, fill factor and conversion efficiency with the increase of the ZnSiP2 thickness slightly increased first and then decreased. From a higher conversion efficiency point of view, the thickness of the ZnSiP2 layer should be optimized to 0.5-2 m. In addition, the doping concentration of ZnSiP2 layer over 1 x 10(19)cm(-3) is advantageous for obtaining a higher fill factor and conversion efficiency. Furthermore, the minority carrier lifetime should be as high as possible so that the diffusion length of the photo-generated carriers is longer than the thickness of ZnSiP2 layer. With the optimum unit design of p-ZnSiP2/n-Si heterojunction solar cells, an enhanced conversion efficiency 22.1765% is demonstrated by the simulation under the given simulation conditions.