• Carbon nanotubes;
  • MWCNT forest;
  • Plasma activation;
  • Porous silicon

CVD enhanced by remote plasma is applied to produce carbon film material on silicon substrates. The layers of aligned multiwall carbon nanotubes (MWCNT) are obtained without a metal catalyst by deposition from a methane/hydrogen gas mixture activated by a direct current (DC) discharge. The individual MWCNTs in the films consist of 4–7 concentric carbon shells with a spacing of 0.34 nm. An absence of metallic impurities in the MWCNT film material is confirmed using energy dispersive X-ray (EDX) and electron energy loss spectroscopy (EELS) analyses. A proposed model explains the formation of the cylindrical seeds of the MWCNTs via condensation of carbon atoms from the activated gaseous environment on the inner surfaces of pores, created in the substrate material as a result of silicon etching by ionized hydrogen, generated in the DC discharge plasma. Further growth of these seeds during the CVD process leads to the formation of MWCNT forests.