Post-treatment method for improving field emission from carbon nanotubes/nanofibers

Abstract:

A novel post-treatment method is reported for improving the field emission characteristics of screen-printed carbon nanotubes/nanofibers (CNTs/CNFs) cathodes. After the treatment at the temperature of 500°C in H₂ and C₂H₂ gas for 20 minutes, the CNTs/CNFs cathodes exhibit much better field emission properties than those untreated. The emission current increases from 0.02 mA/cm² to 0.5 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 orders in magnitude. 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. Supported by Funds of Trans-Century Talents Project of State Education Ministry and Shanghai Nanotechnology Promotion Center (0452nm048)