Welding method for fabricating carbon nanotube probe

A simple and reliable welding method was developed to fabricate carbon nanotube probe used in atomic force microscopy here. First, apply less than 20 V voltage between silicon probe and carbon nanotube when they were in close proximity under direct view of optical microscope. Then, let carbon nanotube contact with silicon probe and increase the external voltage to 30–60 V until carbon nanotube was divided and attached to the end of silicon probe. The fabricated carbon nanotube probe could be shortened to appropriate length by electron bombard. The weld strength of carbon nanotube probe was calculated by drawing the ordinary AFM probe and measuring the probeʹs deflections. For one carbon nanotube probe with 75 nm diameter, the weld strength was calculated more than 268 nN. Carbon nanotube probe showed higher aspect ratio and could more accurately reflect the true topography of sample than silicon probe.