Formation of Nano-pillar Iron Catalyst Nucleating the Multi-walled Carbon Nanotube Growth

摘要

The nano-form of iron catalyst for the carbon nanotubes(CNTs)growth was prepared in a separate process.First,a thin iron layer was thermally deposited under a high vacuum onto the surface of the SiCVSi substrate at about 300 K.That catalyst surface was treated with hydrogen at 700°C,followed by a subsequent heating at 750°C in the pure ethylene atmosphere.After the hydrogen treatment a continuous,smooth Fe layer was turned into a set of well separated Fe nano-pillars.Deposited multi-walled CNTs(MWCNTs)were examined with atomic force(AFM),scanning electron(SEM)and high resolution transmission electron(HR-TEM)microscopic techniques.Applied pretreatment of the catalyst with hydrogen and chemical vapour deposition of MWCNTs from pure ethylene allowed to propose the growth mechanism for long,straight and catalyst free MWCNTs.It seems that this kind of CNTs structure is the most serious candidate in a future nano-electronic.The results suggest a certain control of the diameter of CNTs.