Electrical resistivity of polypyrrole nanotube measured by conductive scanning probe microscope: The role of contact force

Polypyrrole (PPy) nanotubes were synthesized using the pores of track-etched polycarbonate membrane as a template. Its size depends on the pore diameter of template, range from 50 to 200 nm. Direct I-V measurements of PPy nanotube (diameter of 120 nm) deposited on Au were done using a metal-coated tapping-mode atomic-force-microscope tip. Linear I-V characteristics are observed, and the resistance is decreased as the contact force is increased. Using the Hertz model, the elastic modulus E and electrical resistivity rho are estimated to be Esimilar to1 GPa and rhosimilar to1 Omegacm. These values are consistent with those obtained in bulk PPy film. (C) 2002 American Institute of Physics.