Metal-oxide electron tunneling device for solar energy conversion

• US 6,534,784 B2
• Filed: 05/21/2001
• Issued: 03/18/2003
• Est. Priority Date: 05/21/2001
• Status: Expired due to Term

• 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.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Ho, Tu-Tu
• Application Number:
  US09/860,988
• Publication Number:
  US 20020171078A1
• Time in Patent Office: 666 Days
• Field of Search: 257/25, 257/17, 257/21, 136/206, 136/255
• 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 amorphous insulating layer configured such that using only said first amorphous insulating layer in the arrangement would result in a given value of nonlinearity in said transport of electrons, with respect to said given voltage, and

ii) a different, second insulating layer disposed directly adjacent to and configured to cooperate with said first amorphous insulating layer such that the transport of electrons includes, at least in part, transport by means of tunneling through said first amorphous insulating layer and said second insulating layer, and such that said nonlinearity, with respect to said given voltage, is increased over and above said given value of nonlinearity by the inclusion of said second insulating layer without the necessity for any additional layers.

2. The electron tunneling device of claim 1 wherein said first amorphous insulating layer is further configured such that using only said first amorphous insulating layer in the arrangement would result in a given value of differential resistance in said transport of electrons, with respect to said given voltage, and wherein said second insulating layer is further configured to cooperate with said first amorphous insulating layer such that said differential resistance, with respect to said given voltage, is decreased below said given value of differential resistance by the inclusion of said second insulating layer without the necessity for any additional layers.

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

4. The electron tunneling device of claim 1 wherein said second insulating layer is formed of an amorphous insulator.

5. The electron tunneling device of claim 4 wherein said first amorphous insulating layer and said second insulating layer are formed of different, amorphous insulators.

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

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

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

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

10. 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, for directing said electromagnetic energy to a specific location within said electron tunneling device and for converting the electromagnetic energy so received into said given voltage provided across the first and second non-insulating layers at least at said specific location.

11. The electron tunneling device of claim 10 wherein the antenna structure is configured to receive electromagnetic energy over a broad range of frequencies.

12. The electron tunneling device of claim 11 wherein said broad range of frequencies includes frequencies from near-ultraviolet to near-infrared.

13. 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.

14. The electron tunneling device of claim 1 wherein said arrangement consists essentially of said first amorphous insulating layer and said second insulating layer.

15. 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 consisting essentially of a plurality of thin, insulating layers, said plurality of thin, insulating layers including at least two different insulator materials and being configured such that the transport of electrons includes, at least in part, transport by means of tunneling through said plurality of thin, insulating layers.

16. 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 amorphous insulating layer, such that using only said first amorphous insulating layer in the arrangement would result in a given degree of nonlinearity in said transport of electrons between the first and second 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 steps of:

positioning a different second insulating layer between said first and second non-insulating layers and directly adjacent to said first amorphous insulating layer and configuring said second insulating layer to cooperate with said first amorphous insulating layer such that the transport of electrons includes, at least in part, transport by means of tunneling through said first amorphous insulating layer and said second insulating layer such that said nonlinearity is increased without the necessity for any additional layers.

17. The method of claim 16 wherein said step of positioning the second insulating layer includes the step of forming the second insulating layer of an amorphous insulator material.

18. The method of claim 17 herein said step of forming the second insulating layer includes the step of depositing the amorphous insulator material by sputtering.

19. The method of claim 16 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.

20. The method of claim 16 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.

21. The method of claim 16 further comprising the steps of configuring the first and second non-insulating layers to form an antenna structure for receiving electromagnetic energy, for directing said solar energy to a specific location and for converting the electromagnetic energy so received into said given voltage provided across the first and second non-insulating layers at least at said specific location.

22. The method of claim 21 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.

23. The method of claim 22 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.

24. 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) a first arrangement including first and second non-insulating layers spaced apart from one another and configured to form an antenna for receiving said solar energy incident thereon and for directing said solar energy to a specific location within said electron tunneling device; and

b) at said specific location, a second 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 second arrangement including

i) a first amorphous insulating layer, and

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

25. The device of claim 24 wherein said second insulating layer is formed of an amorphous insulator.

26. The device of claim 24 wherein the first non-insulating layer is formed a first metal, and the second non-insulating layer is formed of a different, second metal.

27. The device of claim 24 wherein the first and second non-insulating layers are both formed of a given metal.

28. The device of claim 24 wherein the first and second arrangements are configured to form a diode structure.

29. The device of claim 28 wherein said first and second arrangements are further configured such that said the diode structure functions as a rectifier.

30. The device of claim 28 wherein the first and second arrangements are further configured such that the device exhibits a negative differential resistance when the given voltage is in a predetermined range of values.

31. The device of claim 24 wherein said antenna is a broadband antenna structure for receiving the solar energy, for directing said solar energy to said specific location and for converting the solar energy so received into said given voltage provided across the first and second non-insulating layers at least at said specific location.

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

b) a second 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 second arrangement including

i) a first amorphous insulating layer such that using only said first amorphous insulating layer 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 different, second insulating layer disposed directly adjacent to and configured to cooperate with said first amorphous insulating layer such that the transport of electrons includes, at least in part, transport by means of tunneling through said first amorphous insulating layer and said second insulating layer, 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 by the inclusion of said second insulating layer without the necessity for any additional layers.

33. The electron tunneling device of claim 32 wherein the transport of electrons includes, at least in part, transport by means of resonant tunneling.

34. The electron tunneling device of claim 32 wherein the first and second non-insulating layers are configured to form an antenna structure for receiving electromagnetic energy as said input energy and for directing said solar energy to a specific location within said electron tunneling device.

35. The electron tunneling device of claim 34 wherein the antenna structure is configured to receive electromagnetic energy over a broad range of frequencies.

36. The electron tunneling device of claim 35 wherein said broad range of frequencies includes frequencies from near-ultraviolet to near-infrared.

37. 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 form an antenna for receiving said solar energy incident thereon and for directing said solar energy to a specific location within said device; and

b) at said specific location, 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 insulating layer, and

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

38. The device of claim 37 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.

39. The device of claim 37 wherein the first and second non-insulating layers are both formed of a given metal.

40. The device of claim 37 wherein said first amorphous insulating layer and said second insulating layer are formed of different, amorphous insulators.

41. 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 insulating layer such that using only said first amorphous insulating layer 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 different, second insulating layer disposed adjacent to and configured to cooperate with said first amorphous insulating layer such that the transport of electrons includes, at least in part, transport by means of tunneling through said first amorphous insulating layer and said second insulating layer, and such that the solar energy incident on the first and second electrically conductive 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 by the inclusion of said second insulating layer without the necessity for any additional layers.

42. The device of claim 41 wherein the first electrically conductive layer is formed of a first metal, and wherein said second electrically conductive layer is formed of a different, second metal.

43. A method for converting solar energy 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 such that a given voltage can be provided therebetween, and configuring said first and second non-insulating layers to form an antenna structure for receiving said solar energy incident thereon and for directing said solar energy to a specific location;

b) at said specific location, positioning an arrangement between the non-insulating layers, said arrangement including a first amorphous insulating layer and a different, second insulating layer disposed directly adjacent to said first amorphous insulating layer; 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.

44. The method of claim 43 wherein said step of configuring the arrangement includes the step of forming the second insulating layer of an amorphous insulator.

45. The method of claim 43 wherein said step of configuring the arrangement includes the step of configuring the first and second non-insulating layers, the first amorphous insulating layer and the second insulating layer to form a diode structure.

46. The method of claim 43 wherein said step of configuring the first and second non-insulating layers includes the step of configuring said antenna as 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.

47. An electron tunneling device comprising:

a) first and second pon-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 insulator and a second layer of a different amorphous insulator disposed directly adjacent to said first layer of amorphous insulator, said arrangement being configured such that the transport of electrons includes, at least in part, transport by means of resonant tunneling.

48. 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 and to said first and second non-insulating layers, said arrangement including

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

ii) a different, second insulating layer disposed directly adjacent to and configured to cooperate with said first amorphous insulating layer such that the transport of electrons includes, at least in part, transport by means of tunneling through said first amorphous insulating layer and said second insulating layer, and such that said asymmetry, with respect to said given voltage, is increased over and above said given value of asymmetry by the inclusion of said second insulating layer without the necessity for any additional layers.

49. 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 and to said first and second non-insulating layers, said arrangement including

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

ii) a different, second insulating layer disposed directly adjacent to and configured to cooperate with said first amorphous insulating layer such that the transport of electrons includes, at least in part, transport by means of tunneling, and such that said differential resistance, with respect to said given voltage, is decreased below said given value of differential resistance by the inclusion of said second insulating layer without the necessity for any additional layers.

50. 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 amorphous insulating layer configured such that using only said first amorphous insulating layer in the arrangement would result in a given value of nonlinearity in said transport of electrons, with respect to said given voltage, and

ii) a different, second insulating layer disposed directly adjacent to and configured to cooperate with said first amorphous insulating layer so as to provide a quantum well through which resonant tunneling occurs upon application of said given voltage across the first and second non-insulating layers such that the transport of electrons between and to said first and second non-insulating layers through said first amorphous insulating layer and said second insulating layer includes, at least in part, transport by means of resonant tunneling, and such that said nonlinearity, with respect to said given voltage, is increased over and above said given value of nonlinearity by the inclusion of said second insulating layer without the necessity for any additional layers.

51. The electron tunneling device of claim 50 wherein said arrangement is further configured to include at least one, and no more than two, quantum well when said given voltage is provided across the first and second non-insulating layers such that said transport of electrons includes at most four segments of tunneling from said first non-insulating layer to reach said second non-insulating layer.