Tip cooling effect and failure mechanism of field-emitting carbon nanotubes.

The cooling effect accompanying field electron emission has been considered for a single carbon nanotube (CNT) used as a field emission (FE) electron source. An improved model for the failure mechanism of field emitting CNTs has been proposed and validated. Our model predicts a maximum temperature (T-max) located at an interior point rather than the tip of the CNTs, and the failure of the CNT emitters tends to take place at the T-max point, inducing a segment by segment breakdown process. A combination of Joule heating and electrostatic force effect is proposed responsible for initiating the failure of the field emitting CNT and validated by in situ FE observation.