Field emitters and devices

摘要

A broad area field electron emitter comprises a plurality of emitter cells of layered structure. Each cell comprises a hole having a layer of field electron emission material 501 at its base. A gate electrode 503 is spaced from the emitter layer 501 by a dielectric material 502 having a first region in contact with the emitter layer 501 and a second region in contact with the gate electrode 503 . The cell diameter is greater at the level of the gate 503 than at the level of the emitter layer 501 , thus enabling electrons in electron beam 505 and emitted from sites adjacent to the side walls of the cell to avoid interception by the gate 503 at point 506 . This reduces cell-wall charge between the first and second regions of dielectric material 502 , and other means for achieving this are disclosed.