▎ 摘　　要

NOVELTY - Preparing diamond-multilayer graphene composite cathode material comprises (i) grinding the silicon substrate in the diamond powder uniformly and compactly, (ii) placing the ground silicon substrate into the suspension liquid made of diamond powder for 30-30 hours to finish the seed crystal, (iii) sealing the organic small molecule liquid source in a stainless steel tank with a constant temperature water bath groove, and (iv) the pressure difference between the saturated vapor pressure of the liquid source is in the stainless steel cell and the deposition chamber, conveying the organosilicone liquid source to the deposition room to crack into the required group, and depositing to obtain the diamond- multilayer graphite-polysilyl-graphene composite cathode material. USE - Preparation of diamond-multilayer graphene composite cathode material used in field emission display, vacuum microwave device, X-ray source (tube) and vacuum microelectronic system field. ADVANTAGE - The diamond-multilayer graphene composite cathode material has low opening electric field and high emission current density, and has excellent field emission performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a diamond-multilayer graphene composite cathode material.