Advances in silicon surface texturization by metal assisted chemical etching for photovoltaic applications

Abstract

New Si processes based on Metal Assisted Chemical Etching (MACE) are explored for solar cells texturization. Pt and Au are considered as catalysts for MACE of p and n-type Si substrates. 2D band bending modeling at the nanoscale shows that Pt nanoparticles (NPs) make ohmic contacts and induce delocalized etching. Accordingly, cone-shaped macropores, very efficient in reducing the reflectivity $(< 5\%)$ are obtained experimentally. On the contrary, Au with n-type Si leads to non-ohmic contacts and localized etching. On this basis, a novel strategy for 3D pattern transfer into Si with patterned nanoporous gold electrodes in a single step is developed.