Patent ID: 6046542
Filing Date: 2000-04-04
Classification: H01J

Abstract:
An electron device including a thin-film electron emitter comprising a semiconductor film, the emitter having an emission area comprising a plane area of a front major surface of the semiconductor film from which hot electrons are emitted in operation of the emitter, an injector electrode at a back major surface of the semiconductor film from which electrons are injected into the semiconductor film, electron-accumulation means for providing an accumulation layer of electrons at the emission area of the semiconductor film, and a front electrode located beside the emission area and electrically connected laterally to the electron accumulation layer to determine the surface potential at the emission area for controlling the magnitude of electron accumulation at the emission area and for extracting excess electrons not emitted from the emission area, the emission area being free of the front electrode, and the semiconductor film having such a thickness as to support a depletion layer from the injector electrode to the electron accumulation layer when the emission area is biased by the front electrode sufficiently positively with respect to the injector electrode for injecting the electrons from the injector electrode into the semiconductor film in operation of the emitter, the depletion layer establishing from the injector electrode to the emission area an electric field in which the electrons are heated and directed towards the emission area.