Quantum dots in carbon nanotubes

Carbon nanotube has an extremely small diameter of the order of a few nanometers, and can be semiconducting or metallic, depending on its chirality. These facts make the nanotube a possible building block for the quantum dot and wire based device with dimensions which are not easily realized by using conventional microfabrication techniques. Although there need a lot of studies on the manipulation of the nanotube to construct the practical device, recently it has become possible to make electrical contacts to individual nanotubes to measure the electronic transport. In this talk, we report on our experimental attempt to form quantum dots in nanotubes, and demonstrate that they show the single electron transport which is popular in semiconductor quantum dots, with the larger charging energy and zero dimensional confined level spacing.