PHOTOEMISSIVE ELECTRON TUBE COMPRISING A THIN FILM TRANSMISSIVE SEMICONDUCTOR PHOTOCATHODE STRUCTURE

摘要

A transmissive semiconductor photocathode structure comprising a first monocrystalline epitaxial layer of silicon or germanium about 200 to 300 nanometers thick on a major surface of a transparent monocrystalline dielectric substrate. On the silicon or germanium layer is a second monocrystalline epitaxial layer of a III-V or II-VI semiconductor compound having a thickness of at least about three microns. On the second layer is a third monocrystalline epitaxial layer of a III-V semiconductor compound having an energy bandgap smaller than the second layer compound and having a thickness on the order of from about one micron to about five microns.