SANDWICHED ULTRA THIN SILVER INSTEAD OF NANOPARTICLES AS AN ALTERNATIVE BROADBAND ANTI-REFLECTION COATING FOR C-SI SOLAR CELL APPLICATIONS

摘要

Dielectric-metal-dielectric sandwiched structure as an alternative device geometry for minimizing the reflection in context of c-Si solar cell application has been explored along with nanoparticle based reflection minimization concept. The study suggests that Ag nanoparticles are very good in minimizing reflection in infrared wavelength region but there is high reflection in UV-Vis region which is the main implication for its use for c-Si based solar cell application. The high reflection in UV-Vis region for nanoparticle based anti-reflection structure has been correlated with calculated backscattering from nanoparticles as per Mie solution of Maxwell equations for scattering from small particles. The alternate solution for minimizing the reflection from c-Si solar cell front surface is shown using dielectric-metal-dielectric sandwiched structure (SiN_x-Ag-SiN_x). For the sandwiched structure, the weighted total reflectance for wavelength range 300 nm- 1200 nm is 7.2 % which is 48 % lesser than standard 80 nm silicon nitride (SiN_x) based anti-reflection device structure for non-textured Si surface which gives 13.8 %. The results suggest that the dielectric-metal-dielectric sandwiched structure is more promising than the nanoparticle based device structure for reflection minimization in broadband wavelength range (300 nm- 1200 nm). And this can give much better anti reflection (AR) property than standard SiN_x based ARC on non textured Si surface which is more relevant for thin c-Si based solar cells application where tradition texturing may not be promising.