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Vertically oriented single wall nanotubes (SWNTs) and few walled nanotubes (FWNTs) have been grown by electronic cyclotron resonance plasma enhanced chemical vapor deposition (PECVD) on silica flat substrates. The impact of the plasma parameters on SWNT and FWNT growth has been investigated using two different etching gas mixtures, namely, C2H2/NH3 and C2H2/H2 with various ratios and applied bias voltages. Kinetic studies are also proposed in order to describe the FWNT growth mechanism by plasma techniques. A key role played by the reactive gas (NH3 and H2) is observed in the PECVD process, contrary to multiwalled nanotube growth. It is demonstrated that the balance between FWNT growth versus FWNT etching can be widely modulated by varying the gas mixture and bias voltage. It is shown that the use of hydrogen for hydrocarbon gas dilution restricts the destruction of SWNT and FWNT by the plasma species (ions and radicals). [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on carbon nanotubes (CNT) arrays grown on patterned catalysts by plasma-enhanced chemical vapor deposition (PECVD). CNT growth has been performed by low pressure high-density plasma process at 700°C in acetylene/ammonia mixture. Prior to CNT growth, a standard lift-off process has been used for catalyst patterning. The chemical impact of the lift-off sequence on the catalyst activity is discussed with respect to the amount of Ni pre-deposited. In particular, it discusses the impact of this wet treatment on CNT growth when the catalyst amount is lower than a threshold value. [Copyright &y& Elsevier]

This letter reports low-pressure, room-temperature growth of carbon nanofibers containing nitrogen by plasma chemical vapor deposition arrangement. By alternating pure acetylene plasma and afterglow pure nitrogen high dense plasma, a fine control of the fibers growth kinetic is obtained. This layer-by-layer deposition technique takes advantage of nitrogen chemical etching effects during the growth of nitrogen-doped carbon nanofibers. [ABSTRACT FROM AUTHOR]