GaP negative-electron-affinity cold cathodes

A new GaP junction structure for negative-electron-affinity (NEA) cold cathodes is proposed in order to obtain a higher emission efficiency and a narrower energy distribution of the emitted electrons. Highly efficient GaP NEA cold cathodes with the proposed junction structure were fabricated by improving material technology. A typical efficiency of electron emission for a (100) -oriented GaP surface was about 0.7%. The energy distribution of the emitted electrons from the cold cathode had a full width at half-maximum of about 0.3 eV. At present, the cold cathodes have been operating continuously in excess of 3000 h at an emission current density of about 10−3 A/cm2.