Dynamic work function shift in cold cathode emitters using current carrying thin films

We analyze a new cold cathode emitter which consists of a thin wide band gap semiconductor material sandwiched between a metallic material, and a low work function semimetallic thin film. We show that under forward bias operation the electrons captured in the low work function material are responsible for an effective reduction of the semimetallic film work function, together with a substantial increase of the cathode emitted current. The dynamic work function shift is shown to increase with the amount of injected current. Potential material candidates are suggested to achieve low-voltage (<20 V), room-temperature cold cathode operation with emission currents approaching several hundred A/cm(2) and large efficiencies. (C) 1996 American Institute of Physics.