Role of Gate in Triode-Structure for Carbon Nanotube Cold Cathode

?Field emission properties of carbon nanotube cold cathode (CNT-CC) of triode- and diode-structure have been investigated by using the finite element method of numerical simulation. Specially, the effects of gate voltage and hole radius R on the emission properties have been analyzed based on the finite element method. Results indicate that the gate can make the excitation electric field E increase, turn-on voltage decrease, and the emission current density J rise. The result shows that the E reaches its maximum value at the top of carbon nanotube (CNT), and the optimum field emission performance can be obtained when R is equal to 10 times the diameter of the carbon nanotube.