▎ 摘　　要

NOVELTY - Field emission cathode based on graphene/metamaterial composite nanostructures comprises a base material on which a patterned vertical carbon nanotube array or a patterned microtip array and a graphene material compounded with it are arranged. USE - The cathode is useful in the field of high brightness and coherent electron sources. ADVANTAGE - The cathode has small size, fast response, large current density, environmental tolerance and compatibility with micromachining technology. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing a field emission cathode based on a graphene/metamaterial composite nanostructure comprising (a) spin-coating and pattern the photoresist on the base material, (b) sputtering the catalytic layer and removing excess photoresist to obtain a patterned catalytic layer structure, (c) performing wet transfer of graphene to the patterned catalytic layer and (d) growing vertical carbon nanotubes on the patterned catalytic layer structure, when the patterned vertical carbon nanotube array is arranged on the base material.