Field emission properties of a carbon nanotube cathode in different electric field modes

A large area carbon nanotube cathode was fabricated by spray deposition. The emission properties of the cathode were investigated in both direct current and pulse mode experiments. In the direct current mode, the cathode has high field enhancement factor and high emission current density. In the pulse mode, steady intense-current electron beams were obtained from the cathode. The average current density is 108 A/cm2 at an electric field of 16.7 V/μm. The uniformity and quality of electron beams were investigated, and they were very good. The carbon nanotube cathode is suitable for not only field emission display applications but also high-power microwave device applications.