Effect of the topology of a graphene/SiC nanotip emitter on the formation of rings in high electric fields

The distributions of the electric field strength, current density, and trajectories of emitted electrons have been simulated taking into account the topology of a graphene/SiC nanotip emitter. The analysis of the resulting models has shown an increase in the electric field strength and current density on concentric nanobulges at the periphery of the emitter. It has been shown that nanobulges are sources of the intense emission of electrons. The superposition of trajectories of these electrons results in the appearance of several rings on an emission image.