high currents

The article presents the latest published in the literature data on the development and research of promising field emitters made from carbon nanotubes, graphene and semiconductors. The possibilities of obtaining high densities and currents of field emission, as well as opportunities to ensure long-term operation of emitters in high-voltage electron devices are analyzed.

Achievements and problems in creation of field emitters for vacuum microwave devices are described. The main attention is devoted to the emitters made of containing carbon materials for  high-voltage devices operating at technical vacuum conditions 10¡6–10¡8 Torr. The brief review of existing works is presented. Results of investigations performed in SPbSPU are described.