High density field emitting semiconductor cathode

This paper describes a new high density field emitting cathode which has possible applications in electron guns for cathode-ray tubes, display tubes and other electronic devices. On the surface of the cathode is a large array of micron size electron emitting projections which have been generated initially by an electronic forming method and maintained during operation by a regenerative process. The number density of the emitting centers is many orders of magnitude larger than that attainable in conventional field emission cathodes. Densities as high as 50,000 centers per sq. cm have been achieved with relative ease and higher densities appear feasible. To date up to 100 hours of life have been obtained with a germanium cathode at a current density of 0.5 amps/cm². Densities as high as 1.0 amp/cm²have been achieved-from an emitting area 0.1 cm × 0.1 cm square of germanium and silicon.