On the use of new oxidized Co-Cr-Pt-O catalysts for vertically-aligned few-walled carbon nanotube forest synthesis in electron cyclotron resonance chemical vapor deposition

摘要: A new class of the multi-element catalysis system, Co–Cr–Pt–O, is used for vertically-aligned few-walled carbon nanotube (CNT) forest synthesis by a sandwich-growth technology in electron cyclotron resonance chemical vapor deposition. The effect catalyst compositions on resulting particle sizes after pretreatment, and influence process parameters CNT heights diameters are investigated. Results show that plasma pretreatment step reduces metal oxides present as-deposited Co–Cr–Pt–O to their metallic states or mixed metallic/oxidic states, co-catalytic synergistic during reduction thus leads production uniformly small particles with size 3.3–3.9 nm over substrate. Moreover, CH4 as source, forests ∼12 μm height achieved, further characterizations indicate consist dominant triple-walled nanotubes an average inner tube diameter 3.2–3.7 mostly. Additionally, field emission measurements turn-on CNT-forest emitters below 2.6 V/μm, current density can reach 110 mA/cm2 at 4.5 V/μm. High reproducibility characteristics Raman signals suggests regularity structure size.