Theoretical analysis of the performance of a diffraction grating back- reflector in infrared-sensitive solar cells

The increase of cell efficiency resulting from using a diffraction grating as a back reflector is investigated. An enhancement coefficient is introduced as a figure of merit that accounts for the ability of the rear grating to increase the generation of electric carriers. According to results in this paper, a diffraction-grating-like relief on the rear face of the photovoltaic cell may reduce the intensity of the specular reflection while favouring the intensity of high-angle rays. In this way, the path-length of reflected rays increases, and so does the efficiency of the cell.