A surface-conducted field emission device with suspended graphene cathodes

A surface-conducted field emission device using suspended graphene film as field emitter is fabricated, where the tetrapod-like zinc oxide (T-ZnO) nanostructure is used as surface conducting emitter and supporting structure for the suspended graphene film. The suspended graphene film locates parallely to the gate electric field, leading to high local electric field at the graphene edges. High emission efficiency (30%) is obtained at low operation bias (<150 V) by depositing magnesium oxide film on the surface of T-ZnOs nanostructure. Highlights ► 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.