Hierarchical Multi-Diameter Single-Crystal Silicon Nanowires by Successive Wet Chemical Etching

A simple and low cost top-down wet chemical etching method was developed to fabricate hierarchical multi-diameter well-ordered single-crystal silicon nanowires. The procedure starts with forming single diameter silicon nanowire arrays by using nanosphere lithography and metal-assisted chemical etching of single crystal silicon wafer, which is followed by anisotropic radial etching of the wires. Successive repetitions of these etching steps result in arrays of multi-diameter single crystal nanowires. This technique can allow engineering nanowires in a hierarchical three-dimensional geometry for the development of advanced nano devices.