A study of field electron emission from carbon nanoclusters

The present work is devoted to the investigation of the characteristics of field emission from carbon nanoclusters (nanotubes, nanodiamonds and their composites) produced by cold destruction from natural graphite. Field emission microscopy and scanning electron microscopy were used to study the structure of the emitting surface. It was shown from the field emission image that this structure has high density of emission centers of approximately equal efficiency. Also, the field emission current varies with electric field, observed from current-voltage characteristics, in accordance with the Fowler-Nordheim law. Investigations of the emission properties of carbon nanoclusters confirmed that field emission from these materials takes place in electric fields more than two orders of magnitude lower than in metals and semiconductors. The current-voltage characteristics investigated in a wide range of currents (4 orders of magnitude) give a positive evidence that the mechanism of electron emission from these materials is linked to tunneling emission. No clear interpretation exists at the moment of the extremely low threshold field for the electron emission from carbon nanoclusters.