A surface-conducted field emission device with suspended graphene cathodes

► A surface-conducted field emission device based on graphene cathode is fabricated. ► The Graphene cathode is suspended on tetrapod-like zinc oxide (T-ZnO) nanostructure. ► High electric field can be achieved at the graphene edges. ► High emission efficiency can be achieved by coating MgO film on T-ZnO nanostructure.