Field emitter array

FEAs need to be distinguished from "film" or "mat" type large-area sources, where a thin film-like layer of material is deposited onto a substrate, using a uniform deposition process, in the hope or expectation that (as a result of statistical irregularities in the process) this film will contain a sufficiently large number of individual emission sites.

The device is named after Charles A. Spindt, who developed this technology at SRI International, publishing the first article describing a single emitter tip microfabricated on a wafer in 1968.

Because Spindt tips have sharp apices, they can generate a high local electric field using a relatively low gate voltage (less than 100 V).

Using lithographic manufacturing techniques, individual emitters can be packed extremely close together, resulting in a high average (or "macroscopic") current density of up to 2×107 A/m2 [citation needed].

FEAs offer a number of potential advantages over conventional thermionic cathodes, including low power consumption, instantaneous switching, and independence of current and voltage.

Silicon Carbide (SiC) Field Emitter made by NIST in 2013. It produces a flow of electrons comparable to thermionic emission but without a need for destructive heat. It was made by etching some material away to make a porous structure with a large surface area. As an electron emission point on an individual spike wears out, another is available to replace it, making the array more durable. [ 1 ] [ 2 ]