Fabrication of nanoscale device using individual colloidal gold nanoparticles

A simple technique is presented for the fabrication of nanoscale devices. Commercially available bare gold colloidal nanoparticles are first trapped between two prefabricated large gap electrodes to form a metallic bridge by the application of an AC electric field. The nanoparticle bridge is then broken by slowly ramping a DC voltage across the junction until the current drops to zero. This simple, highly reliable and reproducible technique consistently produces metallic electrodes with less than 10 nm gap and can be applied to prefabricated electrodes up to 1 μm separation. The nanogaps created are ideally suited to contacting individual nanostructures. The paper describes an electrical transport study of a thiol coated 3 nm gold nanoparticle that shows a clear Coulomb staircase.