Abstract: Cylinder and cuboid were fixed in circular copper by conductive silver glue to form 3D type cold cathode, surface electric field distribution of cylinder and cuboid was analyzed by finite element analysis software ANSYS.The cylinder diameter is 12.7 mm, the cuboid cathode surface is square and length is 12.7 mm.Two kinds of cathode have the same height.The carbon nanotube film (CNTs) were synthesized on the surface of cylinder and cuboid by chemical vapor deposition (CVD) and iron phthalocyanine (FePc) as catalyst.The morphology of carbon nanotubes were characterized by field emission scanning electron microscopy (FESEM).By using the diode structure and ITO conductive glass coated with phosphorpowder as anode, the field emission characteristics of two 3D type cold cathodes were measured in a vacuum chamber when the vacuum degree was 2×10-4 Pa.The results show that the field emission performance of the cuboid cathode is better than the cylinder cathode with the increase of the maximum ratio of the two cathode electric field intensity.

Key words: Cylinder and cuboid were fixed in circular copper by conductive silver glue to form 3D type cold cathode, surface electric field distribution of cylinder and cuboid was analyzed by finite element analysis software ANSYS.The cylinder diameter is 12.7 mm, the cuboid cathode surface is square and length is 12.7 mm.Two kinds of cathode have the same height.The carbon nanotube film (CNTs) were synthesized on the surface of cylinder and cuboid by chemical vapor deposition (CVD) and iron phthalocyanine (FePc) as catalyst.The morphology of carbon nanotubes were characterized by field emission scanning electron microscopy (FESEM).By using the diode structure and ITO conductive glass coated with phosphorpowder as anode, the field emission characteristics of two 3D type cold cathodes were measured in a vacuum chamber when the vacuum degree was 2×10-4 Pa.The results show that the field emission performance of the cuboid cathode is better than the cylinder cathode with the increase of the maximum ratio of the two cathode electric field intensity.