A conceptual model of the diffuse transmittance of lamellar diffraction gratings on solar cells

Diffraction gratings are effective ways of increasing the light absorption of solar cells and the light extraction of light-emitting diodes. In this paper, we show that simplified modal analysis can be used as a conceptual model for understanding the behavior of the diffuse transmittance of lamellar diffraction gratings on infinite substrates. We use simplified modal analysis to predict the optimum values of period and height for the gratings, and achieve excellent agreement with rigorous coupled wave analysis. Furthermore, we show that for thin film solar cells with front surface gratings and flat rear reflectors, modal analysis can be used to predict the optimum parameters for maximum light trapping. (c) 2007 American Institute of Physics.