ABSTRACT
All the perfect carbon single-walled nanotubes can be constructed by rolling up a single graphene sheet, and the structures of tubule can be visualized as a conformal mapping of a two-dimensional graphene lattice onto the surface of a cylinder. The use of chemically modified nanotubes instead of pure carbon tubules increases their utility in molecular electronics. The incorporation of the nitrogen atom, which has one more electron than carbon, elevates the Fermi level and shifts it to the conduction band of the pure carbon nanotube. Carbon nanotubes are synthesized by the Chemical Vapor Deposition and laser ablation methods. Carbon nanotubes can be utilized as sheaths to stabilize monoatomic chains, which are unstable alone, and can be applied in many fields. Advances in carbon nanomaterials science stimulated interest in noncarbon analogues of nanotubes. As early as in 1994, quantum mechanical tight-binding calculations predicted the existence, stability, and basic electronic properties of tubules based on hexagonal Boron Nitride.
