Quantum dots in carbon nanotubes

A technology to fabricate electrical contacts on individual single-wall carbon nanotubes has been developed, and electrical measurements are carried out below 4.2 Kelvin. The electrical transport property at low temperatures has basically been characterized as a quantum dot with a pronounced Coulomb blockade effect and zero dimensional confined levels. A microwave response to the nanotube quantum dot is also studied to further characterize the quantum dot. It is discussed how and where the tunnel barrier is formed to realize the quantum dot in a sample. The microwave irradiation effect on the quantum dot turns out to be a classical modulation of the source drain voltage, and is discussed considering the various energy and time scales associated with the transport.