Anisotropic nanoparticles as shape-directing catalysts for the chemical etching of silicon

Anisotropic Au nanoparticles have been used to create a library of complex features on silicon surfaces. The technique provides control over feature size, shape, and depth. Moreover, a detailed study of the etching rate as a function of the nanoparticle surface facet interfaced with the silicon substrate suggested that the etching is highly dependent upon the facet surface energy. Specifically, the etching rate for Au nanocubes with {100}-terminated facets was ~1.5 times higher than that for triangular nanoprisms with {111} facets. Furthermore, this work gives fundamental insight into the mechanism of metal-catalyzed chemical etching.