Abstract Submitted to the    NANOTUBE'04 Conference:

Carbon nanotubes (CNTs) have been synthesized by using a properly designed CVD (chemical vapor deposition) equipment. A few nanometer thick patterned layer of iron was evaporated on Si, porous silicon, Si oxide and porous silicon oxide. With such substrates we investigated different CVD synthesis processes and their influence on the control of the patterned growth. In fact, the CNTs have been grown on the Fe-patterned substrates by thermal decomposition of methane at 900 ˚C and 750 torr conditions, by mixing the hydrocarbon with Ar and these results have been compared with those obtained by using acetylene in the same pressure conditions, at a lower substrate temperature of 700 ˚C. All the reported findings show that the CVD patterned growth is more controllable in the latter case, although the acetylene induced growth is a rapid process. Structural and spectroscopic investigations demonstrate the control over the position, the crystalline degree and nature (multi or single-walled) of the so-grown CNTs. Moreover, according to the wetting of the Fe-patterned substrates and the temperature conditions, the nucleation of the CNTs can even be hampered, giving new hints on the control of the CNTs growth.