Field emission properties of Ex-situ and In-situ iron catalyst-grown carbon nanotubes

Carbon Nanotubes (CNTs) are grown using ex-situ and in-situ iron catalyst sources, and their respective Field Emission (FE) properties are investigated. At similar CNT heights (~16 μm), it is found that in-situ catalyst-grown CNT film shows better FE properties than ex-situ catalyst-grown CNT film. At the same time, it is found that in-situ CNTs show enlarged tips, forming “thumbtack”-shaped CNT tips. From the simulation study, enlarged CNT tip emits higher FE current, possibly due to the larger emission area. The obtained results demonstrated that in-situ catalyst-grown CNTs show better FE properties than ex-situ catalyst-grown CNTs.