ABSTRACT

Nanotubes in electronic devices are in contact with crystals: the nanotubes are typically located on a crystalline substrate and interact with it, whereas the nanotube ends interact strongly with electrodes for good electric contacts. The hybrid electronic devices have been invented, in which nanotubes are embedded into bulk semiconductors. The metallization of the embedded nanotubes is consistent with the measured transport properties of the tube-semiconductor devices with nanotubes encapsulated in a semiconductor crystal using molecular beam epitaxy. The carbon double-walled nanotubes can be considered as a special case of multiwalled carbon nanotubes. They consist of two concentric graphene cylinders with extremely strong covalent bonding of atoms within the individual graphitic sheets, but very weak van der Waals type interaction between them. While different from the embedded tubes, the theoretical studies of the nanotube electronic structure change due to interwall interaction in double-walled systems have received much attention since 1993.