Fig. 1

Schematic cross-sectional view of the fabrication of Si nanostructures using two-step MACE. a In the first step, AgNPs are electrolessly deposited on the Si surface in an aqueous solution containing AgNO₃ and HF. b In the second step, the AgNPs catalyze the etching of the Si substrate in a solution composed of HF, H₂O₂, and H₂O, leading to the formation of Si nanostructures