Design and fabrication of a DCPECVD system in order to growth of vertically aligned carbon nanotubes and effect of C2H2 concentration and plasma current on the growth behavior of CNTs

Full text: In order to obtain the vertically well-aligned carbon nanotubes (CNTs) at a relatively low temperature with high purity and high yield ,a direct current plasma enhanced chemical vapor deposition (DCPECVD) apparatus has been designed and fabricated. Moreover the effect of C2H2 concentration and plasma current on growth of CNTs has been investigated .The synthesis of DCPECVD CNTs has been carried out in the presence of plasma in two steps: i) reduction step with H2 and NH3 gases for formation of catalyst nano particles, ii)subsequent CNTs growth step with H2 and C2H2 gases. High-resolution transmission electron microscopy images clearly demonstrated the nanotubes to be multiwalled, and the graphitized structures were confirmed from the Raman spectra. Besides the results of scanning electron microscopy (SEM) clearly highlights the link between the plasma, C2H2 amount and CNTs structure. With increase or decrease amount of acetylene from a certain flow rate, cause to destruction results. A comparison between the micrographs of CNTs grown with and without plasma, illustrates that plasma play an important role on the formation of vertical and aligned CNTs. (authors)