Emission characteristics of a gallium arsenide wedge emitter monolithically fabricated with an air bridge and a cantilever anode

GaAs wedge emitters with an air bridge and a cantilever anode were monolithically fabricated using a micromachining technique. The threshold voltage of electron emission is about 8 V for the air bridge emitter, while only 1.5 V for the cantilever emitter. The current-voltage characteristic of the air bridge emitter is due to a field emission, while that of the cantilever emitter is recognized as direct tunneling of electrons through the reduction of the air gap between the emitter and cantilever by electrostatic force.