Stable field emission from nanoporous silicon carbide

We report on a new type of cold cathode field emission electron source capable of extremely high emission, producing current densities at levels comparable to thermal sources. Record stable emission in excess of 6 A/cm2 at 7.5 V/μm and a maximum current density of 11 A/cm2 at 9.0 V/μm are demonstrated. The emitter is a unique structure, comprised of a monolithic and rigid nanostructured foam with homogenously distributed emission sites. The fabrication process is simple and scalable, as it consists of wet chemistry and ion etching and does not require high temperature gas phase synthesis. Electric field enhancement is tunable and is set by a two-level hierarchy consisting of local nanostructure morphology and the macroscopic shape.