Use of dielectrophoresis in a high-yield fabrication of a carbon nanotube tip

This paper reports on the development of an atomic force microscope (AFM) tip with single multiwalled carbon nanotube (MWNT). We used an ac electric field, which causes dielectrophoresis (DEP), to align and deposit single MWNT on a metal-coated AFM tip. By dropping an MWNT solution and applying an electric field between the AFM tip and the electrode, we were able to directly assemble one of MWNTs that were dispersed in the diluted solution on the apex of the AFM tip. We investigated the experimental conditions under which the aligning angle of the CNT to the tip's axis varied according to changes in the angle of alignment between the tip and the electrode. We found the experimental condition of 75% success rate to fabricate CNT tips, and we show how the CNT tip compares with a conventional silicon tip with respect to the imaging of 15 nm gold particles.