Pore evolution in metal assisted chemically etched (MACE) porous Si
Final Report Abstract
The project has significantly improved the understanding of the MACE process. There is a better appreciation for the role of aqueous metal ions in silver and copper MACE. The pattern of these metals as catalysts was shown to breakdown, and this suggests a divergence between them and the highly noble gold catalysts. Two different MACE mechanisms now emerge: One where the metal is a localising catalyst for oxidant reactions, and the other where the metal itself acts in its aqueous form as an oxidant in its own right. Gold lies completely in the first case, copper more in the second case, and silver is somewhere in between the two (depending on the parameters used). The role of other aqueous species is also better known as the result of our work, and this allowed us to draw more fundamental connections between the various silicon etching techniques.
