Disclosed herein are various embodiments related to metal-assisted chemical etching of substrates on the micron, sub-micron and nano scales. In one embodiment, among others, a method for metal-assisted chemical etching includes providing a substrate; depositing a non-spherical metal catalyst on a surface of the substrate; etching the substrate by exposing the non-spherical metal catalyst and the substrate to an etchant solution including a composition of a fluoride etchant and an oxidizing agent; and removing the etched substrate from the etchant solution.