Design and Characteristics of a Vertical Carbon Nanotube Sheet Field Emitter

Vacuum electronics devices require high current and high current density cathode. Carbon nanotube (CNT) cold cathode is a good electron source because of its excellent characteristics. To improve its emission area efficiency and weaken the screen effect, a novel type of vertical CNT sheet was introduced which can be fabricated using laser etching method. In field emission test, a single CNT sheet in micrometer scale can emit 13 mA current and 32.5 A/cm² current density in pulse mode. The results demonstrated that the vertical CNT sheet has a great potential to be a high current field emitter which may benefit the application of vacuum electronics devices.