The field emission properties of single-wall carbon nanotubes with purity higher than 70%,which were produced by dc arc discharge evaporation of a carbon electrode including 1% Fe catalyst in H2-Ar mixture gas was studied.The single-wall carbon nanotubes that were produced by this method possess high a ‘clean’ surface since the coexisting Fe catalyst nanoparticles can be completely eliminated by a two-step purification process.The field emission properties was verified by measuring the emission current density(J) versus the applied electric field(E), the corresponding Fowler-Nordheim(F-N) plot for the sample.Through looking at the emission photos, the uniformity of field emission is found to be excellent.

This paper presented a novel post-treatment method of He plasma,which could effectively improve the field emission characteristics of screen-printed CNTs cathodes. Notable changes in the surface morphologies of screen-printed CNTs cathodes were investigated by scanning electron micro scope (SEM) as the f unction of treatment by He plasma.The results showed the post-treated CNTs cathodes hold lower turn-on electric field,higher field emission current density,more emission sites,and better uniformity than those of untreated ones.