Fabrication of Si nanowire arrays selectively formed on pre-patterned (001)Si substrates

We report here the successful fabrication of large-area size-and site-controlled periodic arrays of Si nanowires by employing the colloidal nanosphere lithography technique and Au-assisted selective chemical etching process. The vertically-aligned Si nanowires with diameters down to 190 nm and 90 nm were selectively formed at particular positions on the pre-patterned (001)Si substrates. All the Si nanowires produced were single crystalline in nature and their axial orientations were identified to be parallel to the [001] direction. The experimental results demonstrated that with suitable etching conditions, these synthesis schemes provide the capability to fabricate a variety of periodic arrays of Si-based nanodevices.