Scanning force microscopy characterization of individual carbon nanotubes on electrode arrays

We report the controlled adsorption of individual multi- and single-walled carbon nanotubes from purified aqueous dispersions onto chemically modified silicon oxide surfaces as well as on predefined electrode patterns (100 nm electrode separation). Detailed structural investigations were performed using scanning force microscopy (SFM) without interference from other carbon materials. These studies revealed the striking flexibility of single-walled nanotubes. In contrast to comparably stiff multi-walled nanotubes (MWNTs) which bridged the electrode lines, single-walled nanotubes (SWNTs) were found to follow the profile of the underlying electrodes almost exactly. Based upon the SFM cross sectional analysis of an individual MWNT (8 nm diameter) a Young modulus of about 1 TPa was estimated. Furthermore, nanotube adsorption from the surfactant-stabilized dispersions led to flow-induced orientation processes. (C) 1998 American Vacuum Society. [S0734-211X(98)00605-2].