Gaussian grating for enhancing light absorption by amorphous silicon thin-film solar cells

In this study, a grating with a Gaussian distribution was used to increase the absorption of light by amorphous silicon thin film solar cells. A grating is an effective structure for trapping light inside the active layer of a cell, so a two-dimensional Gaussian grating with a rectangular structure was placed on the front surface of the cell. The results obtained by using the finite element method showed that the Gaussian grating significantly enhanced the absorption of light in the visible and near-infrared ranges by a cell with a thickness of 0.5 mu m compared with a cell without gratings and a cell with normal gratings. The maximum average light absorption by the cell with a Gaussian grating was 84.8%, which was 90% higher compared with the reference cell. In addition, the shortcircuit current density and efficiency were determined as 34.2 and 17.6 mA/cm2, respectively, which were 72% and 72.5% higher, respectively, compared with the reference cell. The proposed structure could be used in a cell to convert more light into electricity.