Chemical etching of Si by Ag nanocatalysts in HF-H2O2: application to multicrystalline Si solar cell texturisation

Metal-assisted chemical etching (MAE) was used as an alter native route to texturise the front surface of multicrystallin Si solar cells. Ag nanoparticles deposited by an electroless method on the Si surface acted as catalysts for Si etching in a solution-containing HF and H2O2, an oxidizing species, MAE< formed a duplex structure at the surface of the Si wafter consisiting in a mesoporous Si layer that after dissolution in NaOH revealed the second structure, which is a macrotexturised surface. After texturisation, the effective reflectivity (AM15G, 1000nm) ranged between 12% and 15% depending on the duration of the dissoltuion treatment of the mesoporous MAE texturised solar cells were compared to NaOH, texturised solar cells made with similar wafers (similar to 25% in effective reflectivity). MAE texturisation leads to a gain in fill factor (FF) but not in shrot circuit current (J(SC)) (from average values). The best MAE cell exhibited higheer J(SC) (2%) and effeciency (16.1%) compared to the best NaOH cell (15.7%). (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim