ELABORATION AND CHARACTERIZATION OF VARIOUS CARBON NANOSTRUCTURES

Evaporation of carbon in the presence of helium produces a large varie ty of carbon cage molecules with quasi-spherical (fullerenes), tubular (carbon nanotubes) and polyhedral (graphitic nanoparticles) morpholog ies. Go-evaporation of carbon with another element (or mixture of elem ents) of the periodic table in the presence of helium yields interesti ng modifications of those structures. The nanotubes can be single- or multi-walled depending on the nature of the additional element and on the experimental conditions. In some cases, the nanotubes as well as t he polyhedral particles can be filled with cylindrical single crystals of the element, while in some other cases an encapsulated carbide is formed. Another way of modifying carbon nanostructures is the substitu tion of B and N into the carbon network. These variations lead to chan ges in the physical properties of the nanostructures.