Thin-film silicon solar cells with efficient periodic light trapping texture

For solar cells based on thin-film microcrystalline (mu c-Si:H) or amorphous silicon (a-Si:H) with absorber layers in the micrometer range, highly effective light trapping and an optimal incoupling of the entire sun spectrum are essential. To investigate and optimize both effects the wave propagation in thin-film silicon solar cells is modeled in three dimensions (3D) solving the Maxwell equations rigorously. A periodic nanostructured texture is investigated as an alternative to the common randomly rough texture. Inverted 3D pyramids with a periodicity of 850 nm and structure height of 400 nm show promising high quantum efficiencies close to the Tiedje limit. (c) 2007 American Institute of Physics.