Optical Waveguide Modes’ Splitting by Bi-Layer Silver Gratings in Thin Film Solar Cells

Abstract

A crystalline silicon thin film solar cell consisting of one-dimensional bi-layer silver back gratings was proposed in this paper. Compared with monolayer silver grating thin film solar cells, more absorption peaks appear in the long wavelength range of the optical spectrum. According to absorption enhancement spectra, two absorption enhancement peaks split into four peaks in the long wavelength range. Electric and magnetic field density profiles show that these peaks come from coupled waveguide modes. Ideal short-circuit current density and electrical performance parameters were calculated. It is found that the splitting of coupled waveguide modes improves the optical absorption of crystalline silicon thin film solar cells.