Atomic force microscopy of single-walled carbon nanotubes using carbon nanotube tip

We succeeded in observing individual single-walled carbon nanotubes (SWNTs) using an atomic force microscope (AFM) in the tapping mode by paying atten tion to the preparation of both samples and AFM tips. To disentangle the bu ndles of SWNTs, we added a small amount of amine into N,N-dimethylformamide . To achieve a high resolution in tapping-mode AFM imaging, we used carbon nanotube (CNT) tips whose radii could be reduced. We were able to image ind ividual SWNTs using CNT tips with widths that were half of those imaged usi ng conventional silicon tips. With this improved resolution, we could clear ly resolve the two SWNTs lying parallel on a mica substrate.