Nanoscale fabrication of a single multiwalled carbon nanotube attached atomic force microscope tip using an electric field

Abstract

We report a simple, repeatable, reliable method and influential conditions for assembling a single multiwalled nanotube (MWNT) to the end of a metal coated atomic force microscope (AFM) tip. The influential conditions consist of the frequency and magnitude of the induced voltage, the concentration of carbon nanotube (CNT) solution and the shape of the tip’s apex. The optimal experimental factors needed for a single MWNT deposition using the dielectrophoretic force were obtained through repeated experiments. Applying an electric field of 0.6 to 0.7Vpp∕μm at 5 MHz, dropping a droplet of the transparent MWNT solution dispersed in the ethanol in a range of 0.5 to 1μℓ, we obtained a CNT AFM tip with just a single MWNT attached. Furthermore, we found that the curvature of the tip’s apex is a great influential factor in a single MWNT-attached tip. We expect that the appropriate size of curvature can improve the yield of single MWNT attachment. The effectiveness of the MWNT-attached AFM tip is demonstrated by direct comparison with AFM images of a bare AFM tip for a standard sample.