Single-Walled Carbon Nanotubes as Templates for Nanowire Conducting Probes

Abstract

We describe a method for the formation of metal nanowires at the apex of scanning probe microscopy (SPM) tips using single-walled carbon nanotubes (SWNT) as templates. The SWNT-SPM tips are sputter coated with metal, here AuPd or Au, resulting in the formation of continuous nanowires as small as 30 nm in diameter and up to a few micrometers in length. In principle, nanowires of any metal, or indeed any material, compatible with the sputter-coating process could be formed. AuPd nanowire tips are shown to be robust enough to allow conducting-mode imaging, over prolonged periods of time, with measured electrical resistance through the AuPd nanowires of less than 10 kΩ and currents of up to 200 μA. The simplicity of this method and its general applicability to the formation of nanowires of a variety of materials make it a promising technique for the formation of a range of nanoelectrodes as well as scanning probes.