Synthesis of carbon nanotubes grown by hot filament plasma-enhanced chemical vapor deposition method

• Published in: Diamond and related materials 2004-02, Vol.13 (2), p.299-304
• Main Authors: Jung, Kyung Ho, Boo, Jin-Hyo, Hong, Byungyou
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Chemical synthesis methods; Chemical vapor deposition; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Hot filament plasma; Materials science; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Physics
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2003.11.056

We prepared two kinds of catalytic layers onto n-typed silicon substrate—nickel by r.f.-magnetron sputtering and iron (III) nitrate metal oxide by spin coating. For iron (III) nitrate metal oxide 0.5 mol of ferric nitrate nonahydrate [Fe 2(NO 3) 3·9H 2O] ethanol solution was coated onto silicon by spin coater at different rotation speeds (rev./min). Carbon nanotubes were synthesized on both Ni and iron (III) nitrate metal oxide layers by the HFPECVD (hot filament plasma-enhanced chemical vapor deposition) method. We used ammonia (NH 3) and acetylene (C 2H 2) for the dilution gas and a carbon precursor for the growth of the carbon nanotubes, respectively. We could observe the relationship between the catalytic cluster density and the nanotube density with scanning electron microscopy (SEM) images. The density of carbon nanotubes on iron (III) nitrate metal oxide was controlled by the rev./min of the spin coater. Transmission electron microscopy (TEM) image shows multi-walled carbon nanotube where the catalyst was found in the tip of the carbon nanotube. Electron dispersive X-ray spectrometry (EDS) peaks for CNT's tip show that it was constituted with nickel and iron, respectively. Raman spectroscopy of nanotubes shows D-band and G-band peaks approximately 1370 and 1590 cm −1.