Photo-electron source assembly with scaled nanostructures and nanoscale metallic photonic resonant cavity, and method of making same

• US 9,966,216 B2
• Filed: 11/05/2012
• Issued: 05/08/2018
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Princeton University
• Original Assignee: Princeton University
• Inventors: Chou, Stephen Y.
• Primary Examiner(s): Gupta, Raj R
• Application Number:
  US14/356,361
• Publication Number:
  US 20160133424A1
• Time in Patent Office: 2,010 Days
• CPC Class Codes: H01J 1/3042 microengineered, e.g. Spindt-type
• CPC Class Codes: H01J 9/025 of field emission cathodes
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H10K 30/30 comprising bulk heterojunctions, e.g. interpenetrating networks of donor and acceptor material domains
• CPC Class Codes: H10K 30/35 comprising inorganic nanostructures, e.g. CdSe nanoparticles
• CPC Class Codes: H10K 30/82 Transparent electrodes, e.g. indium tin oxide [ITO] electrodes
• CPC Class Codes: H10K 39/30 Devices controlled by radiation
• CPC Class Codes: H10K 50/813 characterised by their shape
• CPC Class Codes: H10K 85/113 Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A new ultra-thin high-efficiency photoelectron source utilizing a metallic photonic resonant cavity having a photonic resonant cavity with a top metallic layer with a plurality of openings, each having an average dimension less than the wavelength of the excitation photons in vacuum, a bottom metallic layer and a photoelectron emission layer of semiconductor positioned between the top metallic layer and the bottom metallic.

Claims

1. A photoelectron source comprising a photonic resonant cavity that comprises:

i. a top metallic layer with a plurality of openings;

ii. a bottom metallic layer; and

iii. a photoelectron emission layer of semiconductor positioned between the top metallic layer and the bottom metallic layer,

wherein;

(a) the photoelectron emission layer generates photoelectrons after absorbing excitation photons coming from outside the photonic resonant cavity;

(b) the incoming photons enter the photonic resonant cavity from the top metallic layer;

(c) at least part of the photoelectrons are emitted from the photoelectron emission layer to outside the photonic resonant cavity through the opening in the top metallic layer;

(d) the length of the cavity is configured to enhance the absorption of incoming excitation photons by the cavity; and

(e) a majority of the openings have a dimension less than the vacuum wavelength of the incoming excitation photons.

2. The photoelectron source of claim 1, wherein each of the openings has a shape selected from the group consisting of round, polygon, and triangle or a superposition of one or more thereof.

3. The photoelectron source of claim 1, wherein the openings are the openings between a plurality of metallic disks.

4. The photoelectron source of claim 3 wherein the shape of the disks is selected from the group consisting of round, polygon, and triangle, or a superposition of one or more thereof.

5. The photoelectron source of claim 1 wherein the top metallic layer has a thickness at least a factor of 2 smaller than the wavelength of the excitation photons in vacuum.

6. The photoelectron source of claim 1 wherein the top metallic layer has a thickness about 15 to about 40 nm.

7. The photoelectron source of claim 1 wherein the top metallic layer or the bottom metallic layer is composed of metals selected from the group consisting of a single metal, a mixture of a plurality of metals, and a plurality of layers of two or more metals.

8. The photoelectron source of claim 1 wherein the photoelectron emission layer comprises a semiconductor (organic and inorganic, elements or compounds), which generates electrons upon irradiation of incoming photons.

9. The photoelectron source of claim 1 wherein the photoelectron emission layer is composed of a material selected from the group consisting of Gallium Arsenide (GaAs), Gallium Nitride (GaN), Silicon (Si).

10. The photoelectron source of claim 1 wherein the photoelectron emission layer is composed of one or more materials selected from the group consisting of a single material, a mixture of a plurality of semiconductors, and multiple layers of a plurality of semiconductors.

11. The photoelectron source of claim 1 wherein the photoelectron emission layer includes a coating material on a surface of the photoelectron emission layer facilitating the photoelectron escaping to outside of the photoelectron emission layer.

12. The photoelectron source of claim 11 wherein the coating material is cesium.

13. The photoelectron source of claim 1 wherein the photoelectron emission layer has a short carrier lifetime for the photoelectrons generated by the excitation photons.

14. The photoelectron source of claim 1 wherein the photoelectron emission layer has a thin thickness that is configured to reduce the pulse width of the photoelectrons generated by the incoming photons.

15. The photoelectron source of claim 1 wherein the photoelectron emission layer has a thickness from about 2 nm to about 300 nm.

16. The photoelectron source of claim 1 wherein the photoelectron emission layer has a charge carrier lifetime of about 0.01 ps to about 1 ns.

17. The photoelectron source of claim 1 wherein the photonic resonant cavity further comprises an interface layer positioned either between the photoelectron emission layer and the top metallic layer, or the photoelectron emission layer and the bottom metallic layer.

18. The photoelectron source of claim 1 wherein the excitation photons are generated by the sources selected from the group consisting of a laser, an LED, and a lamp, and are either pulsed or continuums.

19. The photoelectron source of claim 1 wherein the excitation photons are pulsed with a pulse width of about 0.01 ps to about 1 ns.

20. The photoelectron source of claim 1 wherein the photoelectron emission layer is fabricated by thin film deposition.

21. The photoelectron source of claim 1, wherein the openings have an average distance between two nearest neighbor openings smaller than the wavelength of the excitation photons.

22. The photoelectron source of claim 1, wherein the openings has an average distance between two nearest neighbor openings is about 200 nm for the excitation photons of 800 nm wavelength.

23. The photoelectron source of claim 1, wherein the openings are arranged periodically.

24. The photoelectron source of claim 1, wherein the top metallic layer has a thickness of about 1 nm to about 100 nm.

25. The photoelectron source of claim 1, wherein the photoelectron emission layer has a thickness less than a wavelength of the excitation photons.

26. The photoelectron source of claim 1, wherein the top metallic layer and the bottom metallic layer are composed of one or more materials, mixtures of material, alloys and/or layers of materials selected from the group consisting of gold, copper, silver, and aluminum.

27. The photoelectron source of claim 1, wherein the photoelectron emission layer comprise a semiconductor material grown by a low temperature molecule beam epitaxy.

28. The photoelectron source of claim 1, wherein the photoelectron emission layer has a thickness from about 40 nm to about 100 nm.

29. The photoelectron source of claim 1, wherein an electric potential is applied to the bottom or top metallic layer or both.

30. The photoelectron source of claim 1, wherein the excitation photons have a wavelength from about 1 nm to about 30 um.

31. The photoelectron source of claim 1, wherein the photoelectron source further comprises an electron extractor spaced apart from the top metallic layer and exerting an electric field that enhances the escape of the photoelectrons from the photonic resonant cavity.

32. The photoelectron source of claim 31, wherein the electron extractor is powered by DC power supply.

33. The photoelectron source of claim 1, wherein the photoelectron source further comprises a chamber that has a vacuum and wherein the photonic resonant cavity is positioned within the chamber.

34. A method of use the photoelectron source of claim 1, wherein the photoelectron source provides the photoelectrons to a system selected from the group consisting of an electron microscopy, an electron metrology, an electron beam lithography, and an x-ray.

35. The photoelectron source of claim 1, wherein the distance between two neighboring openings is less than the vacuum wavelength of the excitation photons.

36. The photoelectron source of claim 1, wherein the excitation photons have a wavelength in a range from 400 nm to 900 nm.

37. The photoelectron source of claim 1, wherein a majority of the openings have a diameter of about 180 nm.

38. The photoelectron source of claim 1, wherein a majority of the openings have a diameter in a range from about 20 nm to about 75 nm.

39. The photoelectron source of claim 1, wherein the openings are arranged periodically and the periodicity is about 50 nm to about 500 nm.

40. The photoelectron source of claim 1, wherein the openings have an average distance between two nearest neighbor openings that is smaller than the wavelength of the excitation photons.

41. A method of manufacturing the photoelectron source comprising:

having a photoelectron emission layer;

having a top metallic layer that has a plurality of openings and is light transmissive; and

having a bottom metallic layer;

wherein the top metallic layer, the bottom metallic layer, and the photoelectron emission layer in between form a photonic resonant cavity that can resonantly absorb the excitation photons;

wherein;

(a) the photoelectron emission layer generates photoelectrons after absorbing excitation photons coming from outside the photonic resonant cavity;

(b) the incoming photons enter the photonic resonant cavity from the top metallic layer;

(c) at least part of the photoelectrons are emitted from the photoelectron emission layer to outside the photonic resonant cavity through the opening in the top metallic layer;

(d) the length of the cavity is configured to enhance the absorption of incoming excitation photons by the cavity; and

(e) a majority of the openings have a dimension less than the vacuum wavelength of the incoming excitation photons.

42. The method of manufacturing a photoelectron source of claim 41, wherein the top metallic layer is fabricated by at least one method selected from the group of nanoimprinting, electron beam lithography, ion beam lithography, optical lithography, and self-photoelectron source.

43. The method of manufacturing a photoelectron source of claim 41, wherein the photoelectron emission layer is fabricated by lift-off of a thin-film from a substrate.

44. The method of manufacturing a photoelectron source of claim 41, comprising growing the photoelectron emission layer using a low temperature molecule beam epitaxy.