Ab initio study of field emission from graphitic ribbons -: art. no. 127601

We have performed first-principles calculations on field emission (FE) from graphitic ribbons within the time-dependent density-functional theory. An important finding is that dangling bond states localized at clean edges are major contributors to FE current. H termination makes the FE current small due to the disappearance of the dangling-bond states. FE is found not to occur from the edge state of a H-terminated zigzag ribbon even when the state is at the Fermi level. The results of the FE current from graphitic ribbons give similar to1 muA for maximum of FE current from a circular edge of graphitic sheets with similar to1 nm diameter of an open-ended multiwalled carbon nanotube under a high electric field of similar to1 V/Angstrom.