A new AFM-HRTEM combined technique for probing isolated carbon nanotubes

A new technique has been developed for characterizing individual carbon nanotubes (CNTs). This technique combines atomic force microscopy (AFM) measurements with an independent determination of the CNT structure obtained by using thin carbon grid membranes for high-resolution transmission electron microscopy (HRTEM) measurements. The membrane grids are easily transferred onto silicon oxide substrates, where they are observed by AFM and an optical charged-coupled device. Electrostatic force microscopy measurements are also performed on single- and double-walled CNTs whose structures had previously been determined by HRTEM. The results reveal that the diameter and outer tube length have a greater effect on determining the capacitance of the nanotubes than the presence of the inner tube of double-walled CNTs.