▎ 摘　　要

NOVELTY - Graphene field emission cathode comprises conductive substrate (10), growing graphene nanosheets (20) on the conductive substrates in a vertical shape, and metal nanoparticles (30) that are combined on the surface of the graphene nanospheres. USE - Graphene field emission cathode for use in a vacuum electronic device in communication, space technology, safety and medical imaging fields. Can also be used for a metal hot cathode. ADVANTAGE - The graphene field emission cathode can greatly increase the density of the electron emission tip and the number of the effective emission tip, which can improve the field emission current. The graphene nano-sheet surface of the metal nano-particles with graphene electron charge interaction, changing the electronic structure of the graphene, increasing the graphene Fermi level near the state density, and reducing the work function of graphene, so as to reduce the starting electric field of graphene cathode. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing graphene field emission cathode, which involves providing the conductive substrate and processing to clean, preparing mixed solution containing graphene oxide and target metal ion, taking the mixed solution as the electrolyte solution, taking the conductive substrate as the working electrode, using the electro-deposition process of three-electrode system to prepare the graphene field emission cathode, where in the electro-deposition process, the graphene oxide in the mixed solution is deposited on the conductive substrate and is reduced to graphene, formed as a graphene nano-sheet growing vertically, the target metal ion is reduced to metal nano-particles and combined on the surface of the graphene nano-sheet. DESCRIPTION OF DRAWING(S) - The drawing shows a graphene field emission cathode structure schematic diagram. Conductive substrate (10) Graphene nano sheet (20) Metal nano particles (30)