Resonant tunneling electron beam source using GaAs/AlAs/GaAs field emitter

In order to realize a new type of monochromatic electron beam source which incorporates the resonant tunneling effect, methods to form GaAs/AlAs/GaAs field emitters and extract electron beams from them were examined. An undoped GaAs/AlAs/GaAs field emitter showed narrow (0.2 eV) energy distributions almost irrespective with extraction voltages. A δ-doped GaAs/AlAs/GaAs field emitter showed a shoulder. The energy difference between the shoulder and the main peak coincides with that among calculated quantum well subbands. These results suggest the existence of resonant tunneling electron emission in the GaAs/AlAs/GaAs field emitter systems.