Mounting multi-walled carbon nanotubes on probes by dielectrophoresis

We developed a dielectrophoresis method by employing an AC voltage to align, assemble and bridge multi-walled carbon nanotubes (MWNTs) between two oppositely aligned probes. The opposite probes with a gap less than 20 µm were submerged into MWNT suspension solution and an alternative electric field applied between the two probes made MWNTs bridge them. By breaking the bridge, we got MWNT tips, which can find applications in scanning probe microscopes and point electron sources. Field emission properties of the as-prepared MWNT tips were further studied and the maximal emission current was about 25 µA.