In an aspect of this disclosure, a method is provided comprising the steps of: (a) providing a silicon-containing substrate, (b) depositing a first metal on the substrate, (c) etching the substrate produced by step (b) using a first etch, and (d) etching the substrate produced by step (c) using a second etch, wherein the second etch is more aggressive towards the deposited metal than the first etch, wherein the result of step (d) comprises silicon nanowires. The method may further comprise, for example, steps (b1) subjecting the first metal to a treatment which causes it to agglomerate and (b2) depositing a second metal.