GaP negative-electron-affinity cold cathodes: A demonstration and appraisal

Negative-electron-affinity GaP p-n junction cold cathodes have been demonstrated. The emitted currents from these devices are of the expected order of magnitude based on the limiting material and geometric factors. Emission currents suitable for vidicon-type tubes should be readily achievable. Theoretical analyses of the energy distributions of the emitted electrons show significant heating due to electron-phonon scattering. To obtain lower beam temperatures would require a significant advance in material technology.