Fig. 3

Realistic photovoltaic systems. a Schematic drawing of a typical 3D optical model used in the simulations (not to scale); the Ag film (green) and a-Si film (orange) are strictly deposited on the hexagonal periodic nanospheres (gray). b The unit cells of the 300-nm periodic light trapping structure with 160-nm-thick a-Si. The PS spheres in b are not indicated because the Ag film is thick enough to prevent light from transmitting