Electrical behavior of isolated multiwall carbon nanotubes characterized by scanning surface potential microscopy

We measured the surface electric potential distribution on individual, electrically contacted and biased, multiwall carbon nanotubes using scanning surface potential microscopy. The voltage varies linearly along the nanotube and the voltage drop is directly proportional to the bias applied between electrodes. Its resistance decreases four times when a 4.5 V bias is applied between the nanotube and the substrate. Under these conditions, we were able to resolve the voltage drop along the nanotube and at the contacts, providing a unique way of measuring contact resistance, which is observed in this case to be on the order of 50 kOmega. (C) 2002 American Institute of Physics.