Heat-treatment process for effectively enhancing field emission characteristics of CNTs/CNFs cathode

A novel post-treatment method is reported to improve the field emission characteristics of screen-printed carbon nanotubes/nanofibers (CNTs/CNFs) cathodes. After treated at the temperature of 500°C in H₂ and C₂H₂ gas for 20 min, the CNTs/CNFs cathodes exhibit much better field emission properties than those untreated. After the treatment, the emission current increases from 0.02 mA/cm² to 0.50 mA/cm² at 3.9 V/μm with a decrease in the turn-on field from 2.4 V to 1.8 V, and the emission site density is increased by almost four order of number. The enhanced field emission of treated CNTs/ CNFs cathodes is attributed to the appearance of a large number of exposed CNTs/CNFs caused by heat treatment. This surface morphology is very favorable for the electron field emission.