Metal-oxide electron tunneling device for solar energy conversion

• US 20020171078A1
• Filed: 05/21/2001
• Published: 11/21/2002
• Est. Priority Date: 05/21/2001
• Status: Active Grant

• Current Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: Moddel, Garret, Eliasson, Blake J.
• Granted Patent: US 6,534,784 B2
• Time in Patent Office: Days
• US Class Current: 257/25
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 31/035236 Superlattices; Multiple quantum well structures
• CPC Class Codes: H01L 31/06 characterised by potential barriers
• CPC Class Codes: H01L 31/101 Devices sensitive to infrared, visible or ultraviolet radiation
• CPC Class Codes: H10N 70/00 Solid-state devices having no potential barriers, and specially adapted for rectifying, amplifying, oscillating or switching integrated devices or assemblies of multiple devices H10N79/00
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

The electron tunneling device includes first and second non-insulating layers spaced apart such that a given voltage can be provided therebetween. The device also includes an arrangement disposed between the non-insulating layers and configured to serve as a transport of electrons between the non-insulating layers. This arrangement includes a first layer of an amorphous material such that using only the first layer of amorphous material in the arrangement would result in a given value of a parameter in the transport of electrons, with respect to the given voltage. The arrangement further includes a second layer of material, which is configured to cooperate with the first layer of amorphous material such that the transport of electrons includes, at least in part, transport by tunneling, and such that the parameter, with respect to the given voltage, is increased above the given value of the parameter.

Claims

1. An electron tunneling device comprising:

a) first and second non-insulating layers spaced apart from one another such that a given voltage can be provided across the first and second non-insulating layers; and

b) an arrangement disposed between the first and second non-insulating layers and configured to serve as a transport of electrons between said first and second non-insulating layers, said arrangement including

i) a first layer of an amorphous material configured such that using only said first layer of the amorphous material in the arrangement would result in a given value of a first parameter in said transport of electrons, with respect to said given voltage, and

ii) a second layer of material configured to cooperate with said first layer of the amorphous material such that the transport of electrons includes, at least in part, transport by means of tunneling, and such that said first parameter, with respect to said given voltage, is increased over and above said given value of said first parameter.

2. The electron tunneling device of claim 1 wherein said first parameter in said transport of electrons is nonlinearity.

3. The electron tunneling device of claim 1 wherein said first parameter in said transport of electrons is asymmetry.

4. The electron tunneling device of claim 1 wherein said first layer of amorphous material is further configured such that using only said first layer of the amorphous material in the arrangement would result in a given value of a second parameter in said transport of electrons, with respect to said given voltage, and wherein said second layer of material is further configured to cooperate with said first layer of the amorphous material such that said second parameter, with respect to said given voltage, is decreased below said given value of said second parameter.

5. The electron tunneling device of claim 4 wherein said second parameter in said transport of electrons is differential resistance.

6. The electron tunneling device of claim 1 wherein said first layer of amorphous material exhibits a first conduction band height, and wherein said second layer of material exhibits a second conduction band height, which second conduction band height is substantially different from said first conduction band height.

7. The electron tunneling device of claim 1 wherein said second layer of material is positioned directly adjacent to the first layer of the amorphous material.

8. The electron tunneling device of claim 1 wherein the first layer of the amorphous material is formed of an amorphous insulator.

9. The electron tunneling device of claim 8 wherein said second layer of material is formed of an amorphous insulator.

10. The electron tunneling device of claim 9 wherein said first layer of amorphous material and said second layer of material are formed of different, amorphous insulators.

11. The electron tunneling device of claim 1 wherein the first non-insulating layer is formed a first metal, and wherein the second non-insulating layer is formed of a different, second metal.

12. The electron tunneling device of claim 1 wherein the first and second non-insulating layers are both formed of a given metal.

13. The electron tunneling device of claim 1 wherein the transport of electrons includes, at least in part, transport by means of resonant tunneling.

14. The electron tunneling device of claim 1 wherein the first and second non-insulating layers, the first layer of the amorphous material and the second layer of material cooperate to form a diode structure.

15. The electron tunneling device of claim 1 wherein the first and second non-insulating layers are configured to form an antenna structure for receiving electromagnetic energy and converting the electromagnetic energy so received into said given voltage provided across the first and second non-insulating layers.

16. The electron tunneling device of claim 15 wherein the antenna structure is configured to receive electromagnetic energy over a broad range of frequencies.

17. The electron tunneling device of claim 16 wherein said broad range of frequencies includes frequencies from near-ultraviolet to near-infrared.

18. The electron tunneling device of claim 1 wherein the arrangement is further configured to result in a negative differential resistance in said transport of electrons for a predetermined range of voltage values for said given voltage.

19. An electron tunneling device comprising:

a) first and second non-insulating layers spaced apart from one another such that a given voltage can be provided across the first and second non-insulating layers; and

b) an arrangement disposed between the first and second non-insulating layers and configured to provide a transport path for electrons between said first and second non-insulating layers, said arrangement including a plurality of thin, non-insulating layers separated by a plurality of thin, insulating layers, said plurality of thin, non-insulating layers being configured to cooperate with said plurality of thin, insulating layers such that the transport of electrons includes, at least in part, transport by means of tunneling.

20. In an electron tunneling device including (i) first and second non-insulating layers spaced apart from one another such that a given voltage can be provided across the first and second non-insulating layers, and (ii) an arrangement disposed between the first and second non-insulating layers and configured to serve as a transport of electrons between said first and second non-insulating layers, said arrangement including a first layer of an amorphous material, such that using only said first layer of the amorphous material in the arrangement would result in a given degree of nonlinearity in said transport of electrons between the non-insulating layers, with respect to said given voltage, a method for increasing said nonlinearity in said transport of electrons, with respect to said given voltage, over and above said given degree of nonlinearity, said method comprising the step of:

positioning a second layer of material between said first and second non-insulating layers, said second layer of material being configured to cooperate with said first layer of amorphous material such that the transport of electrons includes, at least in part, transport by means of tunneling.

21. The method of claim 20 wherein said step of positioning the second layer of material includes the step of disposing the second layer of material directly adjacent to the first layer of the amorphous material.

22. The method of claim 20 further comprising the step of forming the first layer of an amorphous insulator material.

23. The method of claim 22 wherein said step of positioning the second layer of material includes the step of forming the second layer of an amorphous insulator material.

24. The method of claim 23 wherein said step of forming the second layer of the amorphous insulator material includes the step of depositing the amorphous insulator by sputtering.

25. The method of claim 20 further comprising the step of configuring said arrangement such that the transport of electrons includes, at least in part, transport by means of resonant tunneling between said first and second non-insulating layers.

26. The method of claim 20 further comprising the step of configuring said arrangement such that the arrangement cooperates with said first and second non-insulating layers to form a diode structure.

27. The method of claim 20 further comprising the steps of configuring the first and second non-insulating layers to form an antenna structure for receiving electromagnetic energy and converting the electromagnetic energy so received into said given voltage provided across the first and second non-insulating layers.

28. The method of claim 27 wherein said step of configuring the first and second non-insulating layers to form the antenna structure includes the step of configuring the antenna structure to receive electromagnetic energy over a broad range of frequencies.

29. The method of claim 28 wherein said step of configuring the antenna structure includes the step of designing the antenna structure to be receptive to frequencies from near-ultraviolet to near-infrared.

30. A method for fabricating an electron tunneling device on a substrate, said method comprising the steps of:

a) forming a first non-insulating layer having a predetermined shape on the substrate;

b) oxidizing the first non-insulating layer such that an oxide layer is integrally formed in the first non-insulating layer, said oxide layer serving as a first amorphous layer;

c) depositing a second layer of material directly adjacent to the oxide layer; and

d) forming a second non-insulating layer, wherein said second layer of material being configured to cooperate with the first amorphous layer such that the first amorphous layer and the second layer of material together serve as a transport of electrons between the first and second non-insulating layers and said transport of electrons includes, at least in part, transport by means of tunneling.

31. The method of claim 30 wherein said step of forming said first non-insulating layer includes the step of defining said predetermined shape by lithography.

32. The method of claim 31 wherein said step of forming said first non-insulating layer further includes the steps of:

i) depositing a bond layer of a first non-insulating material;

ii) depositing a contact layer of a different, second non-insulating material; and

iii) lifting off of excess first and second non-insulating materials, wherein said first non-insulating material is selected such that the second non-insulating material more readily adheres to the bond layer than directly to the substrate.

33. A device for converting solar energy incident thereon into electrical energy, said device having an output and providing the electrical energy at the output, said device comprising:

a) first and second non-insulating layers spaced apart from one another and configured to receive said solar energy incident thereon; and

b) an arrangement disposed between the first and second non-insulating layers and configured to serve as a transport of electrons between said first and second non-insulating layers, said arrangement including

i) a first layer of an amorphous material, and

ii) a second layer of material configured to cooperate with said first layer of the amorphous material such that the transport of electrons includes, at least in part, transport by means of tunneling, and such that the solar energy incident on the first and second non-insulating layers, at least in part, is extractable as electrical energy at the output.

34. The device of claim 33 wherein said second layer of material is positioned directly adjacent to the first layer of the amorphous material.

35. The device of claim 33 wherein said amorphous material is an amorphous insulator.

36. The device of claim 33 wherein said second layer of material is formed of an amorphous insulator.

37. The device of claim 33 wherein the first non-insulating layer is formed a first metal, and the second non-insulating layer is formed of a different, second metal.

38. The device of claim 33 wherein the first and second non-insulating layers are both formed of a given metal.

39. The device of claim 33 wherein the first and second non-insulating layers, the first layer of the amorphous material and the second layer of material are configured to form a diode structure.

40. The device of claim 39 wherein the diode structure functions as a rectifier.

41. The device of claim 39 wherein the first and second non-insulating layers and the first layer are configured such that the device exhibits a negative differential resistance when the given voltage is in a predetermined range of values.

42. The device of claim 33 wherein the first and second non-insulating layers are further configured to form a broadband antenna structure for receiving the solar energy and converting the solar energy so received into said given voltage provided across the first and second non-insulating layers.

43. An electron tunneling device for converting input energy into output energy with a particular value of energy conversion efficiency, said electron tunneling device having an output and providing said output energy at said output, said electron tunneling device comprising:

a) first and second non-insulating layers spaced apart from one another and configured to receive said input energy; and

b) an arrangement disposed between the first and second non-insulating layers and configured to serve as a transport of electrons between said first and second non-insulating layers, said arrangement including

i) a first layer of an amorphous material such that using only said first layer of the amorphous material in the arrangement would result in a given value of energy conversion efficiency, with respect to a given amount of input energy, and

ii) a second layer of material configured to cooperate with said first layer of the amorphous material such that the transport of electrons includes, at least in part, transport by means of tunneling, and such that said energy conversion efficiency, with respect to said given amount of input energy, is increased over and above said given value of energy conversion efficiency.

44. The electron tunneling device of claim 43 wherein said second layer of material is positioned directly adjacent to the first layer of the amorphous material.

45. The electron tunneling device of claim 43 wherein the transport of electrons includes, at least in part, transport by means of resonant tunneling.

46. The electron tunneling device of claim 43 wherein the first and second non-insulating layers are configured to form an antenna structure for receiving electromagnetic energy as said input energy.

47. The electron tunneling device of claim 43 wherein the antenna structure is configured to receive electromagnetic energy over a broad range of frequencies.

48. The electron tunneling device of claim 47 wherein said broad range of frequencies includes frequencies from near-ultraviolet to near-infrared.

50. The device of claim 49 wherein the first electrically conductive layer is formed of a first metal, and wherein the second electrically conductive layer is formed of a different, second metal.

51. The device of claim 49 wherein the first and second non-insulating layers are both formed of a given metal.

52. The device of claim 49 wherein said first amorphous layer and said second layer are formed of different, amorphous insulators.

49. A device for converting solar energy incident thereon into electrical energy, said device having an output and providing the electrical energy at the output, said device comprising:

a) first and second electrically conductive layers spaced apart from one another and configured to receive said solar energy incident thereon; and

b) an arrangement disposed between the first and second electrically conductive layers and configured to serve as a transport of electrons between said first and second electrically conductive layers, said arrangement including

i) a first amorphous layer, and

ii) a second layer disposed directly adjacent to said first amorphous layer and configured to cooperate with said first amorphous layer such that the transport of electrons includes, at least in part, transport by means of tunneling, and such that the solar energy incident on the electrically conductive layers, at least in part, is extractable as electrical energy at the output.

53. A device for converting solar energy incident thereon into electrical energy, said device having an output and providing the electrical energy at the output, said device comprising:

a) first and second non-insulating layers spaced apart from one another and configured to receive said solar energy incident thereon; and

b) an arrangement disposed between the first and second electrically conductive layers and configured to serve as a transport of electrons between said first and second electrically conductive layers, said arrangement including

i) a first layer of an amorphous material such that using only said first layer of the amorphous material in the arrangement would result in a given value of solar energy conversion efficiency, with respect to a given amount of said solar energy incident thereon, and

ii) a second layer of material configured to cooperate with said first layer of amorphous material such that the transport of electrons includes, at least in part, transport by means of tunneling, and such that the solar energy incident on the first and second non-insulating layers, at least in part, is extractable as electrical energy at said output while said solar energy conversion efficiency, with respect to said given amount of said solar energy incident thereon, is increased over and above said given value of solar energy conversion efficiency.

54. The device of claim 53 wherein the first non-insulating layer is formed of a first metal, and wherein said second non-insulating layer is formed of a different, second metal.

55. A method for converting solar energy incident thereon into electrical energy and providing said electrical energy at an output, said method comprising the steps of:

a) providing first and second non-insulating layers, which are spaced apart from one another and a given voltage can be provided therebetween;

b) positioning an arrangement between the non-insulating layers, said arrangement including a first layer of an amorphous material and a second layer of material; and

c) configuring said arrangement to serve as a transport of electrons between said first and second non-insulating layers such that the transport of electrons includes, at least in part, transport by means of tunneling, and such that the solar energy incident on the first and second non-insulating layers, at least in part, is extractable as electrical energy at said output.

56. The method of claim 55 wherein said step of configuring the arrangement includes the step of positioning the second layer of material directly adjacent to the first layer of the amorphous material.

57. The method of claim 55 wherein the step of configuring the arrangement includes the step of forming the first layer of an amorphous insulator.

58. The method of claim 57 wherein said step of configuring the arrangement includes the step of forming the second layer of an amorphous insulator.

59. The method of claim 55 wherein said step of configuring the arrangement includes the step of configuring the first and second non-insulating layers, the first layer of the amorphous material and the second layer to form a diode structure.

60. The method of claim 55 further comprising the step of further configuring the first and second non-insulating layers to form a broadband antenna structure for receiving the solar energy and converting the solar energy so received into said given voltage provided across the first and second non-insulating layers.

61. An electron tunneling device comprising:

a) first and second non-insulating layers spaced apart from one another such that a given voltage can be provided across the first and second non-insulating layers; and

b) an arrangement disposed between the first and second non-insulating layers and configured to serve as a transport of electrons between said first and second non-insulating layers, said arrangement including a first layer of an amorphous material, said arrangement being configured such that the transport of electrons includes, at least in part, transport by means of resonant tunneling.