Critical role of the acetylene content and Fe/C ratio on the thickness and density of vertically aligned carbon nanotubes grown at low temperature by a one-step catalytic chemical vapor deposition process

Antoine Combrisson (1) , Emeline Charon (1) , Mathieu Pinault (1) , Cécile Reynaud (1) , Martine Mayne-L’hermite (1)

1 LEDNA - Laboratoire Edifices Nanométriques

The present work explores the role of the carbon source content and the Fe/C ratio on the synthesis of vertically aligned carbon nanotubes (VACNTs) by one-step aerosol-assisted CCVD operated at a medium temperature (615 °C) on aluminum substrates. The main objective was to overcome the limitations of VACNT growth, constituting a drawback for applications requiring thick VACNTs. By using acetylene as carbon feedstock and ferrocene as a catalyst precursor, we demonstrate that when acetylene content is reduced to 1.5 vol%, it is possible to grow VACNT carpets up to 700 µm thick while maintaining constant VACNT growth for a long duration (up to 160 min). The carbon conversion yield is significantly improved when the acetylene content reaches 1.5 vol%. The Al surface roughness also influences VACNT growth. An optimum Fe/C ratio of 0.8 wt.% coupled with a low acetylene content gives the highest growth rate (5.4 µm/min) ever reported for a thermal aerosol-assisted CCVD process operated at such a low temperature. The CNT number density can be controlled by varying the Fe/C ratio, enabling high density growth (e.g., 1.3 × 10$^{11}$ CNT/cm$^2$).

Mots clés: carbon nanotubes; synthesis; aerosol-assisted CVD; aluminum substrate; growth rate; VACNT thickness; carbon and iron conversion yield

Domaines: Matériaux

Antoine Combrisson, Emeline Charon, Mathieu Pinault, Cécile Reynaud, Martine Mayne-L’hermite. Critical role of the acetylene content and Fe/C ratio on the thickness and density of vertically aligned carbon nanotubes grown at low temperature by a one-step catalytic chemical vapor deposition process. Nanomaterials, 2022, 12 (14), pp.2338. ⟨10.3390/nano12142338⟩. ⟨cea-03818565⟩