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

Abstract

Abstract Metal‐assisted chemical etching (MAE) was used as an alternative route to texturise the front surface of multicrystalline 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 H 2 O 2 , an oxidizing species. MAE formed a duplex structure at the surface of the Si wafer consisting in a mesoporous Si layer that after dissolution in NaOH revealed the second structure, which is a macrotexturised surface. After texturisation, the effective reflectivity (AM1.5G, 400‐1000 nm) ranged between 12% and 15% depending on the duration of the dissolution treatment of the mesoporous layer. MAE texturised solar cells were compared to NaOH texturised solar cells made with similar wafers (∼25% in effective reflectivity). MAE texturisation leads to a gain in fill factor (FF) but not in short‐circuit current (J SC ) (from average values). The best MAE cell exhibited higher J SC (+2%) and efficiency (16.1%) compared to the best NaOH cell (15.7%). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)