Towards solar cells with black silicon texturing passivated by a-Si:H

We introduce surfaces of black silicon (bSi) fabricated by reactive ion etch (RIE) and passivated by hydrogenated amorphous silicon (a-Si:H). We demonstrate minority effective lifetime over 1.5 ms for the best bSi surfaces, corresponding to over 700 mV of implied open circuit voltage, values higher than on reference surfaces prepared by KOH etching. Fabrication of solar cells resulted in promising efficiency of 16.1 % for bSi as compared to 18.5 % for KOH references. Quantum efficiency measurements revealed that the bSi cells lose approximately 0.5 mA cm^-2 of current density in the visible and of 0.8-1 mA cm^-2 in the infrared (IR) region. Current work is ongoing to further reduce surface damage during RIE to maximize the open circuit voltage and to optimize the deposition of a-Si:H on our bSi in order to reduce the loss in current density.