TEM study of the influence of the catalyst composition on the formation and growth of SWNT
ABSTRACT Different TEM techniques have been combined to study the microscopic mechanisms of SWNTs nucleation and growth. Inspection of samples obtained from the different synthesis routes supports a general phenomenological model which is first described. In this model, formation of the nanotubes proceeds via solvation of carbon into liquid metal droplets, followed by precipitation, at the surface of the particles, of excess carbon in the form of nanotubes. The influence of the composition of the catalyst on the nucleation process was then studied in detail in the case of the Ni -RE (RE = Y, La, Ce...) systems, leading to the identification of the respective roles played by Ni and RE.