Quasi-ballistic electron transport in double-wall carbon nanotubes

Room-temperature quasi-ballistic electron transport in double-wall carbon nanotubes (DWNT) is demonstrated. Conductance dependence on the length was measured by submerging DWNTs into liquid mercury. The conductance plots show plateaus, indicating weak dependence of the electrode–tube–electrode electrical resistance on the length of the connecting nanotube. We infer a mean free path between 0.6 and 10 μm for ∼80% of the DWNTs, which is in good agreement with calculations based on the electron scattering by acoustic phonons and by disorder.