ABSTRACT
Carbon nanotubes are either semiconducting or metallic depending on their structures [1-5] as discussed in Chapter 1. Usually, semiconductors are used for metal-semiconductor (Schottky) diodes, pn junction diodes, and field-effect transistors (FETs), whereas metals are used for single-electron tunneling transistors. This situation is more or less the same in nanotube (NT) electronics. In this chapter, semiconducting NT devices will be emphasized. Semiconducting NT characterization is discussed in Section 7.1, followed by doping in Section 7.2, NT FETs in Section 7.3, intermolecular NT Schottky junctions in Section 7.4, and NT pn junctions as Esaki diodes in Section 7.5. Coulomb blockade phenomena are observed in both semiconducting and metallic NTs. Coulomb oscillations and Coulomb diamonds are covered in Section 7.6. In Section 7.7, other semiconducting NT devices are examined, and some topics in metallic NT transport are briefly covered in Section 7.8. Finally, in Section 7.9, general remarks on nanoFETs, including NT FETs, are given.
