Field emission at 10 V cm-1 with surface emission cathodes on negative-electron-affinity insulators -: art. no. 192115

Surface emission cathodes reported here consist of two electrodes separated by similar to 10 mu m on a negative-electron-affinity glass, Cs2Si4O9. The electrodes consist of a W film suspended over the insulator by a gap of 0-70 nm. When electron emission is initiated with a bias of 0-300 V, between the electrodes, the cathodes continue to emit after the bias is removed and for anode voltages as low as 20 V, electric fields < 10 Vcm(-1). The emission is modeled by the electrons tunneling from the electrode onto the glass surface and from there they are emitted into vacuum. Emission without bias is the result of positive charge in the insulator, which replaces the need for a bias voltage. (C) 2005 American Institute of Physics.