Observation of Coulomb blockade in a Ti/multi-wall carbon nanotube/Ti structure

Coulomb blockade effect in a multi-wall carbon nanotube contacted by Ti electrodes in metal-on-tube configuration has been observed. The junction capacitance estimated from the I-V curves is proportional to the length of the nanotube segments overlapped by Ti electrodes, showing that the tunnel barrier does not locate inside the nanotube but between the nanotube and a Ti electrode, that is, the nanotube, as a whole, behaves as an island. The high resistance of the sample, which is crucial for the observation of the Coulomb blockade, can be attributed to mismatch between Ti and nanotube.