SiN_x Double Layer Antireflection Coating by Plasma-Enhanced Chemical Vapor Deposition for Single Crystalline Silicon Solar Cells

Abstract

Double layer antireflection (DLAR) coatings have significant advantages over single-layer antireflection (SLAR) coatings owing to their coverage of a broad solar spectral range. In this study, the properties of SiN x are examined. DLAR coatings using two thin films of SiN x with different refractive indices are presented. Using the same materials is more cost-effective than using different materials. The total thickness of SiN x /SiN x films is kept at 80 nm. The top SiN x film has a refractive index of 1.9, while the bottom layer has a refractive index of 2.3. Single crystalline solar cells are fabricated with different thicknesses for the top and bottom layers. The solar cell with 60 nm/20 nm SiN x DLAR coatings has 18.3% efficiency, while that with 80 nm SiN x SLAR coating has 17.6% efficiency. The improvement of efficiency is due to the effect of better passivation and better antireflection of DLAR.