Electron emission device

• US 20050018467A1
• Filed: 07/22/2004
• Published: 01/27/2005
• Est. Priority Date: 07/22/2003
• Status: Active Grant

• Current Assignee: Yeda Research and Development Co. Ltd. (Weizmann Institute of Science)
• Original Assignee: Yeda Research and Development Co. Ltd. (Weizmann Institute of Science)
• Inventors: Halahmi, Erez, Naaman, Ron
• Granted Patent: US 7,646,149 B2
• Time in Patent Office: Days
• US Class Current: 365/145
• CPC Class Codes: H01J 21/10 with one or more immovable internal control electrodes, e.g. triode, pentode, octode
• CPC Class Codes: H01J 3/021 Electron guns using a field emission, photo emission, or secondary emission electron source

Abstract

An electrons'"'"' emission device is presented. The device comprises an electrodes'"'"' arrangement including at least one Cathode electrode and at least one Anode electrode, the Cathode and Anode electrodes being arranged in a spaced-apart relationship; the device being configured to expose said at least one Cathode electrode to exciting illumination to thereby cause electrons'"'"' emission from said Cathode electrode, the device being operable as a photoemission switching device.

Claims

1. An electron emission device comprising an electrodes'"'"' arrangement including at least one Cathode electrode and at least one Anode electrode, the Cathode and Anode electrodes being arranged in a spaced-apart relationship;

the device being configured to expose said at least one Cathode electrode to exciting illumination to thereby cause electrons'"'"' emission from said Cathode electrode, the device being operable as a photoemission switching device.

2. The device of claim 1, wherein the Cathode and Anode electrodes are spaced by a gas-medium gap.

3. The device of claim 1, wherein the Cathode and Anode electrodes are spaced by a vacuum gap.

4. The device of claim 2, wherein the gas pressure is selected to be sufficiently low to ensure that a mean free path of electrons accelerating from the Cathode to the Anode is larger than a length of the gap between the Cathode and the Anode electrodes.

5. The device of claim 1, wherein the electrodes'"'"' arrangement comprises an array of the Anode electrodes arranged in a spaced-apart relationship.

6. The device of claim 1, wherein the electrodes'"'"' arrangement comprises an array of the Cathode electrodes arranged in a spaced-apart relationship.

7. The device of claim 6, wherein the electrodes'"'"' arrangement comprises an array of the Anode electrodes arranged in a spaced-apart relationship.

8. The device of claim 1, operable to control an electric current between the Cathode and Anode electrodes by varying a potential difference between them, while maintaining a certain illumination of the Cathode electrode, thereby affecting the Anode current.

9. The device of claim 1, operable to control an electric current between the Cathode and Anode electrodes maintained at a certain potential difference between them, by modifying the illumination of the Cathode, thereby affecting the Anode current.

10. The device of claim 1, operable to control an electric current between the Cathode and Anode electrodes by varying a potential difference between them and modifying the illumination of the Cathode, thereby affecting the Anode current.

11. The device of claim 1, wherein the electrodes'"'"' arrangement includes at least one additional electrode electrically insulated from the Cathode and Anode electrodes.

12. The device of claim 11, wherein the additional electrode is configured as a grid located between the Cathode and Anode electrodes.

13. The device of claim 11, wherein the additional electrode is accommodated in a plane spaced-apart from a plane where the Cathode and Anode electrodes are located.

14. The device of claim 11, wherein the electrodes are located in different planes.

15. The device of claim 11, wherein said at least one additional electrode is operable to control an electric current between the Cathode and Anode electrodes.

16. The device of claim 11, operable to control an electric current between the Cathode and Anode electrodes by varying a voltage supply to said at least one additional electrode, while maintaining illumination of the Cathode and maintaining a certain potential difference between the Cathode and Anode electrodes, thereby affecting the Anode current.

17. The device of claim 11, operable to control an electric current between the Cathode and Anode electrodes by varying a voltage supply to said at least one additional electrode and modifying the illumination of the Cathode thereby affecting the Anode current.

18. The device of claim 1, wherein the electrodes are made from metal materials.

19. The device of claim 1, wherein the electrodes are made from semiconductor materials.

20. The device of claim 1, wherein:

one of the Cathode and Anode electrodes is made from metal, and the other from semiconductor material.

21. The device of claim 1, wherein one of the Cathode and Anode electrodes is made from metal, and the other from a mixture of metal and semiconductor.

22. The device of claim 1, wherein the Cathode electrode is coated or doped with an organic or inorganic material.

23. The device of claim 1, wherein the Cathode electrode is formed with a portion thereof having a sharp edge.

24. The device of claim 1, comprising an illuminating assembly operable with a wavelength range including the exciting illumination to cause electrons emission from the Cathode.

25. The device of claim 24, wherein the illuminating assembly includes at least one of the following:

a low pressure discharge lamp, a high pressure discharge lamp, a continuous wave laser device, a pulsed laser device, at least one non-linear crystal, and at least one light emitting diode.

26. The device of claim 25, wherein said illuminating assembly includes a Hg lamp.

27. The device of claim 25, wherein said illuminating assembly includes a Xe lamp.

28. The device of claim 1, wherein, the Cathode and Anode electrodes are made from ferromagnetic materials different in that their magnetic moment directions are opposite, the device being thereby operable as a spin valve, shifting one of the Cathode and Anode electrodes between its SPIN UP and SPIN DOWN states resulting in shifting the device between its inoperative and operative positions.

29. The device of claim 28, comprising a magnetic field source operable to apply an external magnetic field to the electrodes'"'"' arrangement, the application of the external magnetic field shifting said one of the Cathode and Anode electrodes between its SPIN UP and SPIN DOWN states.

30. The device of claim 1, wherein the Cathode electrode is made from non-ferromagnetic metal or semiconductor and the Anode electrode is made from a ferromagnetic material, the device being shiftable between its operative and inoperative positions by varying polarization of the illumination.

31. The device of claim 30, comprising an illuminating assembly operable with a wavelength range including said exciting illumination, the illuminating assembly being configured to produce light of various polarizations.

32. The device of claim 1, wherein the Cathode electrode is made from non-ferromagnetic metal or semiconductor and the Anode electrode is made from a ferromagnetic material, the device being shiftable between its different modes of operation by shifting the Anode electrode between SPIN UP and SPIN DOWN high transmission states.

33. The device of claim 1, wherein the Cathode electrode is located on a substrate transparent for a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing illumination of the Cathode electrode through said transparent substrate.

34. The device of claim 1, wherein the Cathode and Anode electrodes are carried by first and second spaced-apart substrates, respectively.

35. The device of claim 34, wherein the second substrate is transparent for a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing illumination of the Cathode electrode through regions of said second substrate outside the Anode electrode.

36. The device of claim 34, wherein the second substrate and the Anode electrode are transparent for a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing illumination of the Cathode electrode through the Anode electrode.

37. The device of claim 1, wherein the electrodes'"'"' arrangement is an integrated structure comprising first and second substrate layers for carrying the Cathode and Anode electrodes, respectively;

and a spacer layer structure between the first and second substrate layers, the spacer layer structure being patterned to define a gap between the Cathode and Anode electrodes.

38. The device of claim 37, wherein the spacer layer structure comprises at least one dielectric material layer.

39. The device of claim 37, wherein the spacer layer structure comprises first and second dielectric layers and an electrically conductive layer between said first and second dielectric layers, the patterned electrically conductive layer defining an additional electrode.

40. The device of claim 37, wherein the first substrate is made of a material transparent with respect to a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing the illumination of the Cathode through the first substrate.

41. The device of claim 37, wherein the second substrate is transparent for a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing illumination of the Cathode electrode through regions of said second substrate outside the Anode electrode.

42. The device of claim 37, wherein the second substrate and the Anode electrode are transparent for a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing illumination of the Cathode electrode through the Anode electrode.

43. The device of claim 1, wherein the electrodes'"'"' arrangement is an integrated structure comprising a first substrate layer for carrying an array of the spaced-apart Cathode electrodes;

a second substrate layer for carrying an array of the spaced-apart Anode electrodes; and

a spacer layer structure between the first and second substrate layers, the spacer layer structure being patterned to define an array of spaced-apart gaps between the first and second arrays of electrodes.

44. The device of claim 43, wherein the spacer layer structure comprises at least one dielectric material layer.

45. The device of claim 43, wherein the spacer layer structure comprises first and second dielectric layers and an electrically conductive layer between said first and second dielectric layers, the patterned electrically conductive layer defining an array of additional electrodes.

46. The device of claim 43, wherein the first substrate is made of a material transparent with respect to a wavelength range of the exciting illumination causing the electrons emission from the Cathode, thereby allowing the illumination of the Cathode electrodes through the first substrate.

47. The device of claim 43, wherein the second substrate is transparent for a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing illumination of the Cathode electrodes through regions of said second substrate outside the Anode electrodes.

48. The device of claim 43, wherein the second substrate and the Anode electrode are transparent for a wavelength range including the exciting illumination causing the electrons emission from the Cathode, thereby allowing illumination of the Cathode electrodes through the Anode electrodes.

49. An electron emission device comprising an electrodes'"'"' arrangement including at least one Cathode electrode and at least one Anode electrode arranged in a spaced-apart relationship;

the device being configured to expose said at least one Cathode electrode to exciting illumination to cause electron emission therefrom, the device being operable as a photoemission switching device by affecting an electric current between the Cathode and Anode electrodes, the switching being effectible by at least one of the following;

varying the illumination of the ;

the Cathode electrode, and varying an electric field between the Cathode and Anode electrodes.

50. An electron emission device comprising an electrodes'"'"' arrangement including at least one Cathode electrode, at least one Anode electrode, and at least one additional electrode arranged in a spaced-apart relationship;

the device being configured to expose said at least one Cathode electrode to exciting illumination to thereby cause electrons'"'"' emission from said at least one illuminated Cathode electrode towards said at least one Anode electrode;

the device being operable as a photoemission switching device by affecting an electric current between the Cathode and Anode electrodes, the switching being effectible by at least one of the following;

varying the illumination of the Cathode electrode, and varying an electric field between the Cathode and Anode electrodes.

51. An electron emission device comprising an electrodes'"'"' arrangement including at least one Cathode electrode and at least one Anode electrode, the Cathode and Anode electrodes being arranged in a spaced-apart relationship with a gas-medium gap between them;

the device being configured to expose said at least one Cathode electrode to exciting illumination to thereby cause electrons'"'"' emission from said at least one illuminated Cathode electrode, the device being operable as a photoemission switching device.

52. An electron emission device comprising an electrodes'"'"' arrangement including at least one Cathode electrode, at least one Anode electrode, and at least one additional electrode arranged in a spaced-apart relationship;

the device being configured to expose said at least one Cathode electrode to exciting illumination to thereby cause electrons'"'"' emission from said at least one illuminated Cathode electrode towards said at least one Anode electrode;

the device being operable as a photoemission switching device.

53. An integrated device comprising at least one structure operable as an electrons'"'"' emission unit, said at least one structure comprising at least one Cathode electrode and at least one Anode electrode that are carried by first and second substrate layers, respectively, which are spaced from each other by a spacer layer structure including at least one dielectric layer, the spacer layer structure being patterned to define a gap between the Cathode and Anode-electrodes, at least one of the first and second substrates being made of a material transparent with respect to certain exciting radiation to thereby enable illumination of the at least one Cathode electrode to cause electrons emission therefrom, the device being operable as a photoemission switching device.

54. An integrated device comprising at least one structure operable as an electrons'"'"' emission unit said at least one structure comprising at least one Cathode electrode and at least one Anode electrode that are carried by first and second substrate layers, respectively, which are spaced from each other by a spacer layer structure including first and second dielectric layers and an electrically conductive layer between the dielectric layers, the spacer layer structure being patterned to define a gap between the Cathode and Anode electrodes, at least one of the first and second substrates being made of a material transparent with respect to certain exciting radiation to thereby enable illumination of the Cathode electrode to cause electrons emission therefrom, the device being operable as a photoemission switching device.

55. An integrated device comprising an array of structures operable as electrons'"'"' emission units, the device comprising a first substrate layer carrying the array of the spaced-apart Cathode electrodes, a second substrate layer carrying the array of the spaced-apart Anode electrode;

and a spacer layer structure between said first and second substrates, the spacer layer structure including at least one dielectric layer and being patterned to define an array of gaps, each between the respective Cathode and Anode electrodes, at least one of the first and second substrates being made of a material transparent with respect to certain exciting radiation to thereby enable illumination of the Cathode electrode to cause electrons emission therefrom, the device being operable as a photoemission switching device.

56. A method of operating an electron emission device as a photoemission switching device, the method comprising illuminating a Cathode electrode by certain exciting radiation to cause electrons'"'"' emission from the Cathode electrode towards an Anode electrode, and affecting the switching by at least one of the following:

controllably varying the illumination of the Cathode, and controllably varying an electric field between the Cathode and Anode electrodes.

57. An electron emission device, comprising an electrodes'"'"' arrangement including at least one unit having at least one Cathode electrode and at least one Anode electrode, the Cathode and Anode electrodes being arranged in a spaced-apart relationship with a gas-medium gap between them of a length substantially not exceeding a mean free path of electrons in said gas medium.

58. The device of claim 57, wherein the length of the gap between the Cathode and Anode electrodes substantially does not exceed 800 nm.

59. The device of claim 57, wherein the length of the gap between the Cathode and Anode electrodes is of about a few tens of nanometers.

60. The device of claim 57, wherein the length of the gap between the Cathode and Anode electrodes is from a few tens of nanometers to a few hundreds of nanometers.

61. An electron emission switching device, comprising an electrodes'"'"' arrangement including at least one unit having at least one Cathode electrode and at least one Anode electrode, the Cathode and Anode electrodes being arranged in a spaced-apart relationship with a gas-medium gap between them of a length substantially not exceeding a mean free path of electrons in said gas medium.