▎ 摘　　要

NOVELTY - A fractal graphene material with negative electron affinity, comprises single layer and multiplayer fractal graphene structures growing alternately, which is deposited on substrate. USE - Fractal graphene material used in field emission display, cold cathode electric light source, X-ray source, electronic beam welding and cold cathode electronic source apparatus (claimed). ADVANTAGE - The material has strong field electron emission ability and high structural stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparing fractal graphene material comprising: (A) selecting and cleaning substrate suitable for growing graphene; (B) loading the cleaned substrate to magnetron sputtering reaction chamber, filling inert gas, starting electrode, forming plasma, bombarding the target with plasma, and depositing metal layers on base material as substrate; (C) transferring the substrate to super high temperature chemical vapor deposition reaction chamber, starting heating device, warming to 600-800 degrees C, filling mixed gas of reaction gas and carrier gas, and inert gas, forming plasma, accelerating speed by the electrode, making reaction ion to bombard the substrate physically and react chemically, and growing uniform carbon nanoparticle layers on surface of the substrate; (D) warming the reaction furnace to 1000-1400 degrees C, improving carrier gas proportion, reducing concentration of carbon based gas, reducing deposition speed of carbon atom, and depositing fractal graphene material on substrate surface; and (E) maintaining temperature at 1000-1400 degrees C, filling carrier gas to reaction furnace, and rearranging and purifying the graphene material. The reaction gas is carbon based gas. The carrier gas is hydrogen, ammonia and/or nitrogen.