Abstract Submitted to the ; NANOTUBE'05 Conference:

We have studied large-scale synthesis and characterization of high-quality double-walled carbon nanotubes (DWCNTs) using a catalytic chemical vapor deposition method and a hydrogen arc discharge method. For the synthesis of DWCNTs using a catalytic CVD method, we used various carbon containing molecules such as methane, THF and propanol over Fe-Mo embedded MgO support material. The produced carbon filaments indicated high-purity DWCNTs free of amorphous carbon on the surface. The diameters of DWCNTs were dependent on process conditions, carbon sources and support materials. In this work, DWCNTs by methane indicated smaller diameters compared with DWCNTs by THF or propanol. By adopting a hydrogen arc discharge method, we could obtained high-purity DWCNTs in large-scale. In this work, we used FeS promoter and Fe catalyst to synthesize DWCNTs effectively. The purity and yield of produced DWCNTs by arc discharge were mainly dependent on catalyst concentration and reaction pressure. Transmission electron microscopy, Raman analysis and TGA showed that produced carbon materials had low defect level in the atomic carbon structure, indicating the synthesis of high-quality DWCNTs. We have evaluated field emission from DWCNTs. According to our experimental results, DWCNTs showed low turn-on voltage similar to SWCNTs and higher emission stability than that of SWCNTs. Interestingly, field emissison performance from DWCNTs largely was dependent on the diameter of nanotube.

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