Growth of vertically aligned carbon nanotubes by DCPECVD system and the effects of C2H2 concentration and plasma current on the growth behavior of CNTs

Abstract EN

In order to synthesize highly pure vertically well-aligned carbon nanotubes (CNTs) at relatively low temperatures, direct current plasma enhanced chemical vapor deposition (DCPECVD) apparatus was designed and fabricated.

Afterward, the effects of C2H2 concentration and plasma current on the growth of CNTs were investigated.

The synthesis of DCPECVD CNTs was carried out in the presence of plasma consisting of two steps: i) reduction with H2 and NH3 gases to form the catalyst nanoparticles, and ii) subsequent CNTs growth step with H2 and C2H2 gases.

High-resolution transmission electron microscopy images clearly illustrate the multi-wall carbon nanotubes (MWCNT) and their graphitized structures were confirmed by the Raman spectra.

Moreover, the results of scanning electron microscopy (SEM) confirmed the close relation between the plasma, C2H2 amount, and CNT growth.

A deviation of acetylene flow rates from the optimum point leads to a deterioration of CNT growth.

A comparison between CNT micrographs, grown with and without plasma, illustrate that plasma plays an important role in the formation of the vertical aligned CNTs.