Nanotechnology of nanotubes and nanowires: From aligned carbon nanotubes to silicon oxide nanowires

Laser etching of Co, Ni and Fe films, in conjunction with the pyrolysis of solid organic precursors (e.g. aminodichlorotriazine, melamine, etc.) generates aligned carbon nanotube bundles and films of uniform length (<200 μm) and diameter (30 A–80 A). However, nanotube alignment strongly depends upon laser etching conditions (e.g. laser power, pulse duration and focus distance). Additionally, condensed-phase techniques, using mixtures of molten LiCl and soft metals (e.g. Bi, Pb, etc.) as electrolytes, generate high yields of metallic nanowires (<45% overall material and <2 μm in length, <100 nm OD). Finally, it is shown that novel 3-D flower-like silica nanostructures are produced by a simple and surprising solid-phase approach. It is observed that single catalytic nanoparticles act as nucleation sites, leading to unusual morphologies of silicon oxide nanofibres (20–120 nm OD and <200 μm). The latter structures may be useful in the context of catalysis, 3-D composite materials, and optoelectronic devices, ...