Enhanced light trapping in thin-film silicon solar cells with concave quadratic bottom gratings.

Abstract

We present a theoretical crystalline silicon thin-film solar cell with concave quadratic bottom gratings using parametric design of the gratings and systematically perform optoelectronic simulations of the proposed grating structures. Numerical results reveal that the concave quadratic grating structure leads to a desirable enhancement of light absorption in the near-IR region (750-1100nm), and this enhancement is dominated by TE-polarized light. The mechanisms of light absorption enhancement under TE-polarized light are based on the hybrid effect of optical waveguide modes and Fabry-Perot modes. Moreover, research results indicate that the concave quadratic grating structure has excellent light-focusing effects, which is conducive to the excitation of optical waveguide modes. The study findings can be utilized to improve the efficiency of thin-film solar cells based on grating structures.