Design and Optimization of Wide Angle Passivation and Antireflection Coating for N-Type High Efficiency Silicon Solar Cells

A SiN_x film is commonly used as a passivation and antireflection coating for P-type silicon solar cells, but for N-type silicon cells, the Al₂O₃ layer was used to passivate boron-doped emitter. In this paper, two different passivation and antireflection films, SiN_x/Al₂O₃ system and SiO₂/SiN_x/Al₂O₃ system were designed for N-type silicon solar cells. In the optimization process, 30° was selected as the optimal angle for antireflection film design, and the oblique incidence properties for two antireflection films in the incidence range from 0° to 60° were also considered. The computation results show that under the same incident angle, the weighted average reflectivity of SiN_x/Al₂O₃ anti-reflection film is higher than that of SiO₂/SiN_x/Al₂O₃ coating. This means, for N-type silicon solar cell, the SiO₂/SiN_x/Al₂O₃ system can effectively reduce light reflection. And at this time the optimal film parameters are: n(SiO₂) = 1.46, d(SiO₂) =104nm, n(SiN_x) = 2.3, d(SiN_x) = 52nm, n(Al₂O₃) = 1.9, d(Al₂O₃) = 10nm.