Field emission electron source for terahertz source application

Field emission from carbon nanotube (CNT) has been simulated by a particle-in-cell (PIC) software at pico-second level. The emission current, current density and focus character of a CNT cathode have been discussed. In a diode configuration, the emission current from cathode reaches 1.85 A/cm2 when the anode voltage is 2 kV. While in a triode configuration, the current reaches 2.3 A/cm2 for a gate voltage of 700 V, and the focus performance of electron beam can be optimized by modifying triode parameters and voltage applied to the electrodes. A diode structure with CNT cathode has been fabricated to verify large-current field emission, a total emission current of 52.1 mA and a current density of 6.6 A/cm2 have been obtained from this diode. It proved that field emission cathode can be applied in terahertz source devices.