International audienceBroadband light trapping is numerically demonstrated in ultra-thin solar cells composed of a flat amorphous silicon absorber layer deposited on a silver mirror. A one-dimensional silver array is used to enhance light absorption in the visible spectral range with low polarization and angle dependencies. In addition, the metallic nanowires play the role of transparent electrodes. We predict a short-circuit current density of 14:6mA=cm2 for a solar cell with a 90 nm-thick amorphous silicon absorber layer

Access to the published version may require subscription. N.B. When citing this work, cite the original published paper.

We propose a design to confine light absorption in flat and ultra-thin amorphous silicon solar cells with a one-dimensional silver grating embedded in the front window of the cell. We show numerically that multi-resonant light trapping is achieved in both TE and TM polarizations. Each resonance is analyzed in detail and modeled by Fabry-Perot resonances or guided modes via grating coupling. This approach is generalized to a complete amorphous silicon solar cell, with the additional degrees of freedom provided by the buffer layers. These results could guide the design of resonant structures for optimized ultra-thin solar cells.