| 摘要 |
A cold electron emitter (200, 200-1, 200-2, 200-3, 200-12, 200-13) may include a heavily n+ doped wide band gap (WBG) (220), a p-doped WBG region (230), and a low work function metallic layer (n<+>-p-M structure) (240). A modification of this structure includes heavily p+ doped (235) region between p region (230) and M metallic layer (n<+>-p-p+-M structure) (240). These structures make it possible to combine high current emission with stable (durable) operation. The high current density is possible because the p-doped (230) or p+ heavily doped (235) WBG region acts as a negative electron affinity material when in contact with low work function metals. The injection emitters with the n<+>-p-M and n<+>-p-p+-M structures are stable since the emitters make use of relatively low extracting electric field and arc not affected by contamination and/or absorption from accelerated ions. In addition, the structures may be fabricated with current state-of-the-art technology. <IMAGE>
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