Enhancement of absorption in thin-film amorphous silicon solar cell with guided mode resonance

The enhancement of absorption in a thin-film amorphous silicon solar cell based on guided mode resonance is theoretically investigated. This is achieved by patterning a single- or double-groove grating with a waveguide layer as the absorbing layer. The optimized grating parameters are obtained by use of rigorous coupled-wave analysis and the simulated annealing algorithm. The averaged integrated absorptions are weakly dependent on the angle of incidence in both grating structures. It is shown the optimized solar cell with double-groove grating has better optical performance than single-groove grating structures. The qualitative understanding of enhanced absorption based on guided-mode resonance and double-groove grating structure is presented. An antireflective grating structure is proposed and discussed for reducing reflection and enhancing absorption. The solar cell with antireflective grating has much better performance than those without an antireflective grating. The designed solar cells have high integrated absorption and are weakly dependent on the incident angle, which should be highly interesting for practical application.