Simulation Design And Optimization Of Amorphous Silicon/crystalline Silicon Heterojunction Solar Cells Based On Localized Pn Junctions

With the development of society and global climate change,the human demand for green and clean energy is increasing again.Photovoltaic,as one of the most promising new energy sources,is gaining more and more attention.Today the global PV market is dominated by crystalline silicon,and further improving the conversion efficiency of crystalline silicon solar cells and reducing the production cost have been the direction of researchers’efforts.In this background,a solar cell with a new structure（heterojunction of a-Si:H/c-Si with localized p-n structure（HACL）solar cell）is designed and simulated in this theses.The structural model of the HACL cell was established using ATLAS simulation software,and the effects of structural and material parameters on the performance of the HACL cell were systematically simulated.The simulation results show that the structure can significantly improve the parasitic absorption loss and can obtain high short-circuit current density while maintaining high open-circuit voltage,which enhances the performance of the solar cell.The main findings obtained are as follows:（1）The selection of lateral dimensions of HACL cells should take into account the generation and collection of photogenerated carriers.An increase in the width of the passivation inlet area of the cell can increase the light absorption area of the cell and generate more photogenerated carriers,but the increase in width will also lead to an increase in the lateral transport distance of more photogenerated carriers and an increase in the chance of carrier compounding.The increase in the width of the local junction facilitates the collection of carriers,but the photogenerated carrier production rate of the substrate is to be reduced.The width of the insulation layer is made as thin as possible while ensuring the insulation effect.The best conversion efficiency is achieved when the area ratio of passivation inlet area width,insulation layer width and local junction width is 12:1:2.（2）For the passivation inlet region,it is feasible to use both n-type doping and p-type doping.The concentration selection of the passivation inlet region needs to consider the field effect passivation and carrier compound.The doping concentration of the passivation inlet region can be increased to increase the field effect passivation,but the concentration increases,and the oscillator compounding rate of carriers also increases.The optimal doping concentration of the passivation inlet region obtained from the simulation is 3×10¹⁸ cm^-3.（3）The optimization of the substrate doping concentration needs to consider the short-circuit circuit density and the filling factor of the cell.As the substrate doping concentration increases,the carrier compounding rate of the substrate increases and the short-circuit current density decreases,but the filling factor of the cell improves,and the optimal doping concentration of the substrate obtained from the simulation is4×10¹⁶ cm^-3.（4）Combining all the data from this simulation.The passivation inlet width and insulating layer width and emitter width are taken as 1200μm,100μm and 200μm,respectively,and the doping concentration of the substrate is 4×10¹⁶ cm^-3,the doping concentration of the passivation inlet area is 3×10¹⁸ cm^-3,and the thickness of both emitter intrinsic hydrogenated amorphous silicon and doped hydrogenated amorphous silicon is 5 nm.The best conversion efficiency can be achieved.The optimized HACL cell parameters are J_sc=43.65 m A/cm2,V_oc=0.758 V,FF=85.19%,and E_ff=28.19%.Through the simulation calculation of HACL cells,the influence law of structural parameters,material parameters and other factors on the device performance is obtained,and the inner physical mechanism of its performance change is revealed,which provides theoretical guidance and reference basis for the practical application of HACL cells.