The growth of Carbon Nanotubes (CNTs) by Silicon Carbide (SiC) surface decomposition appears to be a promising method to scale up CNT production in an accurately controlled way by using simple apparata working in Ultra High Vacuum conditions. The growth of CNT is realized by making use of a single cristal SiC (Carbon terminated) heated at high temperature (~ 1400/1600°C) 1, through current passage, for few hours. In order to follow the electronic structure modifications, we acquire EEL (Electron Energy Loss) during the heating procedure. In this way we observe the carbon nanotubes growth from the beginning in a step by step evolution. In this work, we report on the electronic structure of synthesized carbon products investigated by electron spectroscopy2 and compared with reference to SWCNT/MWCNT, HOPG3 and nanostructured-C samples; we comment their morphology by using the results of SEM analysis and AFM/STM measurements. The vertically alligned nanotubes layer have a very packed surface morphology. In fact, only a mechanical cut of the layer allows us to perform the morphological characterization of the of its inner side. We illustrate a clear relationship between the growth condition (e.g. temperature and growth time) and the structure of the vertically alligned carbon nanotubes bundles. We observed infact different growth lenght of the bundles in dependence of the local temperature on the sample surface. The longest CNT have a 500/600 nm lenght. The next step is the interaction of our nanostractured sample with gold vapours (Au). We will investigate the composite system Au/CNT obtained by evaporation of gold. The electronic, chemical and structural results will show how the gold atoms evaporated on the CNT layer interact with the carbon nanotubes and its eventual re-aggregation.
References:
1 M. Kusunoki, T. Suzuki, T. Hirayama, N. Shibata - Physica B 323 (2002) 296–298
2 G.Chiarello,E. Maccallini,R.G. Agostino,V. Formoso,A. Cupolillo,D. Pacile,E. Colavita,L. Papagno,
L. Petaccia , R. Larciprete ,S. Lizzit ,A. Goldoni - Carbon 41 (2003) 985–992
3 R. G. Agostino et al. - Phys. Rev. B 68, 035413 (2003)
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