Self-assembly of single thin Au nanoparticle chains on Si along V-groove-etched linesbetween micrometre-distant electrodes by dielectrophoresis

Abstract

In this study we investigated the self-assembly of 40 nm size Au colloidal nanoparticles withcitrate stabilization on oxidized flat or V-groove-etched Si substrates betweenmicrometre-distant electrodes using an ac electric field and the technique ofdielectrophoresis. We demonstrated that pre-patterning of the Si surface by formingmicrometre-wide V-groove lines perpendicular to the gold electrodes facilitatessingle nanoparticle chain formation along the V-groove-etched lines. Single thin(∼100–200 nm thick) Aunanoparticle chains 1–10 µm in length were thus formed on oxidized Si between integrated electrodes. The effect of theapplied voltage and frequency of the electric field on nanoparticle chaining was investigatedin detail. The selective growth along the V-grooves was interpreted by considering theelectric field distribution between the electrodes. The samples were characterized byscanning electron microscopy and current–voltage measurements. The Au nanoparticlechains obtained were conductive and are interesting for applications in biomolecule sensing.