Fundamental special projects of key scientific research projects in Higher School of Henan, China（22ZX012）；Key R & D and Promotion Special (science and technology tackling key problems) project of Henan,China（212102210271）；Key scientific research projects in Higher School of Henan, China（21B140010）；Henan University Science and Technology Innovation Team（22IRTSTHN004）；Aeronautical Science Foundation of China（ASFC-2019ZF055002）
In this study, three-dimensional vertical graphene was prepared on copper foil using radio frequency plasma enhanced chemical vapor deposition technology with methane as carbon source. By adjusting the growth parameters, seven groups of comparative experiments were carried out. The morphology, mass and layer number of vertical graphene were characterized by scanning electron microscope and Raman spectroscopy. The field emission characteristics of vertical graphene were measured by a secondary structure field emission instrument. The relationship between the field emission characteristics of vertical graphene and its morphology, mass and density were studied. The open electric field intensity of the field emission characteristic as low as 0.29 V/μm were obtained. The results show that vertical graphene is a material very suitable for field emission application and has broad application prospects in vacuum electron sources in the future.