Atomic Force Microscopy of Single-Walled Carbon Nanotubes Using Carbon Nanotube Tip

Abstract
We succeeded in observing individual single-walled carbon nanotubes (SWNTs) using an atomic force microscope (AFM) in the tapping mode by paying attention to the preparation of both samples and AFM tips. To disentangle the bundles 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 individual SWNTs using CNT tips with widths that were half of those imaged using conventional silicon tips. With this improved resolution, we could clearly resolve the two SWNTs lying parallel on a mica substrate.