Selective self-assembly at room temperature of individual freestanding Ag2Ga alloy nanoneedles

Abstract

Liquid gallium drops placed on thick Ag films at room temperature spontaneously form faceted nanoneedles of Ag2Ga alloy oriented nearly normal to the surface. This observation suggests that single nanoneedles can be selectively grown by drawing silver-coated microcantilevers from gallium. Needles from 25 nm to microns in diameter and up to 33μm long were grown by this method. These metal-tipped cantilevers have been used to perform atomic force microscopy (AFM) and AFM voltage lithography.