Electrical Transport Studies of (n,n) Armchair Carbon Nanotubes

By using Rayleigh scattering spectroscopy, a simple mechanical transfer process, and standard E-beam lithography fabrication of metallic leads, we can probe the electrical properties of individual single-walled carbon nanotubes of known chiral indices (n,m) on the substrate of our choosing. Using these techniques, we have discovered that (n,n) `armchair' nanotubes consistently deviate from the predicted metallic behavior, specifically showing a gap in current -- gate voltage curves. We present detailed studies of the transport behavior of these devices, including conductivity as a function of bias, length, and temperature.