A NEW SURFACE ELECTRON-EMISSION MECHANISM IN DIAMOND CATHODES

An electron-emission mechanism for cold cathodes is described based on the enhancement of electric fields at metal-diamond-vacuum triple jun ctions. Unlike conventional mechanisms, in which electrons tunnel from a metal or semiconductor directly into vacuum, the electrons here tun nel from a metal into diamond surface states, where they are accelerat ed to energies sufficient to be ejected into vacuum. Diamond cathodes designed to optimize this mechanism exhibit some of the lowest operati onal voltages achieved so far.