Inelastic tunnel diodes
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorLynn M. Anderson
Life of this patent
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Abstract
Power is extracted from plasmons, photons, or other guided electromagnetic waves at infrared to mid-ultraviolet frequencies by inelastic tunneling in metal-insulator-semiconductor-metal diodes. Inelastic tunneling produces power by absorbing plasmons to pump electrons to higher potential. Specifically, an electron from a semiconductor layer absorbs a plasmon and simultaneously tunnels across an insulator into a metal layer which is at higher potential. The diode voltage determines the fraction of energy extracted from the plasmons; any excess is lost to heat.
Claims18
Apparatus for using plasmons to convert electromagnetic energy to electrical power comprising
- a first conductive film having one surface adapted for receiving incident electromagnetic energy and an opposite surface adapted to face away from said electromagnetic energy, said first conductive film having a configuration of a diffraction grating,
- an insulating film having said diffraction grating configuration covering said opposite surface of said first electrically conducting film,
- a semiconductor film having said diffraction grating configuration covering said insulating film, said diffraction grating configuration having a predetermined period which causes a mode conversion into junction plasmons with fields localized in said semiconductor film and said insulating film by phase-matching between external electromagnetic waves and said junction plasmons,
- a second conductive film having said diffraction grating configuration covering said semiconductor film thereby forming a diode, and
- an electrical load connected between said first and second conductive films.
A current generator in electrical communication with a load for extracting energy from photons, plasmons, and other guided electromagnetic waves at infrared to mid-ultraviolet frequencies by inelastic tunneling wherein power is produced by absorbing junction plasmons to pump electrons to high potential, comprising:
- a pair of spaced conductive films in electrical contact with said load, a first one of said films having a surface facing away from the other film for receiving incident electromagnetic energy, said surface having a diffraction grating configuration for phase matching incident electromagnetic waves with the junction plasmons,
- an insulating film between said conductive films, said insulating film contacting said first one of said conductive films on the surface thereof facing away from said incident energy receiving surface, and
- a semiconductor film between said conductive films, said semiconductor film contacting said insulating film and the second one of said conductive films to prevent backflow of electrons.
In apparatus for converting sunlight to electricity of the type wherein energy is extracted from photons, plasmons, and other guided electromagnetic waves by dispersing said sunlight over a surface of a conductive member to polarize the surface charge thereon thereby inducing oscillations in the valence electron density at said surface to provide surface plasmons and phase matching photons and surface plasmons of the same energy so that energy is transferred from said photons to said plasmons, the improvement comprising
- tunnel diodes for extracting energy from said electromagnetic waves, each of said tunnel diodes having a diffraction grating configuration for phase matching external electromagnetic waves with junction plasmons.
Dependencies are inferred from the claim text.