ELECTRON EMISSION FROM A COLD CATHODE

摘要

An electron emitter comprising a body of a wide band gap material using double injection space-charge limited current. By using double injection of carriers to establish space-charge limited currents in high resistivity p-type semiconductors, the number of minority carriers can be increased considerably without raising the Fermi level above mid band gap. By using such double injection space-charge limited current a sufficient amount of large energy minority carriers are placed in the conduction band in a p-type semiconductor. A monoatomic layer of cesium and oxygen is positioned on the positively biased contact. This places a negative electron affinity surface layer on the device. The electrons in the conduction band then have enough energy to impel electrons into a vacuum.