Atomic structure, electronic properties, and thermal stability of diamond-like nanowires and nanotubes

Density functional tight-binding calculations are used to investigate the structure, electronic properties, energy stability, and thermal behavior (0–1500 K) of extended monolithic (nanowires) and hollow (nanotubes) diamond-like carbon nanostructures. The results indicate that diamond-like nanowires and nanotubes may be both metallic and semiconducting, depending on their morphology and size. A new type of hybrid (sp 3 + sp 2) nanostructure is identified, which has the form of a monolithic diamond-like (sp 3) wire inside a graphite-like (sp 2) shell. Diamond-like nanowires are shown to be more stable than nanotubes of comparable size.