Fabrication of ultra-thin silicon nanowire arrays using ion beam assisted chemical etching.

Uniform dispersion of Au-Ag alloy nanoparticles underneath the surface of a Si wafer is realized via Au film pre-deposition and Ag ion implantation. The Au-Ag nanoparticles are used as catalysts in metal assisted chemical etching for fabricating Si nanowire arrays with average diameters of less than 10 nm. We find that the alloy catalysts introduced by ion implantation are the key to obtaining thin nanowire arrays and we also demonstrate that SiNWAs with various diameters could be simply produced by changing the thickness of the pre-deposited Au layer. Compared with the traditional process, ion beam assisted chemical etching is proven to be a convenient and efficient approach to fabricate ultra-thin SiNWAs on a large scale.