PIEZOELECTRIC AND SEMICONDUCTING COUPLED NANOGENERATORS

• US 20100117488A1
• Filed: 12/11/2006
• Published: 05/13/2010
• Est. Priority Date: 12/20/2005
• Status: Active Grant

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Wang, Xudong, Wang, Zhong L., Song, Jinhui
• Granted Patent: US 8,330,154 B2
• Time in Patent Office: Days
• US Class Current: 310/339
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H02N 2/18 producing electrical output from mechanical input, e.g. generators for measurement devices G01
• CPC Class Codes: H10N 30/01 Manufacture or treatment
• CPC Class Codes: H10N 30/306 Cantilevers
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

An electrical generator includes a substrate, a semiconductor piezoelectric structure having a first end and an opposite second end disposed adjacent to the substrate, a first conductive contact and a second conductive contact. The structure bends when a force is applied adjacent to the first end, thereby causing an electrical potential difference to exist between a first side and a second side of the structure. The first conductive contact is in electrical communication with the first end and includes a material that creates a Schottky barrier between a portion of the first end of the structure and the first conductive contact. The first conductive contact is also disposed relative to the structure in a position so that the Schottky barrier is forward biased when the structure is deformed, thereby allowing current to flow from the first conductive contact into the first end.

Claims

1. An electrical generator, comprising:

a. a first substrate;

b. a semiconductor piezoelectric structure having a first end and an opposite second end, the second end disposed adjacent to the first substrate, the structure having a flexibility so that the structure bends when a force is applied adjacent to the first end, thereby causing an electrical potential difference to exist between a first side of the semiconductor piezoelectric structure and a second side of the semiconductor piezoelectric structure at a portion of the first end;

c. a first conductive contact disposed so as to be in electrical communication with the first end, the first conductive contact consisting essentially of a material that creates a Schottky barrier between a portion of the first end of the structure and the first conductive contact, the first conductive contact also disposed relative to the structure in a position so that the Schottky barrier is forward biased when the structure is deformed thereby allowing current to flow from the first conductive contact into the first end; and

d. a second conductive contact disposed so as to be in electrical communication with the second end.

2. The electrical generator of claim 1, further comprising a circuit element that is electrically coupled to both the first conductive contact and the second conductive contact.

3. The electrical generator of claim 1, wherein the structure comprises a nano-structure.

4. The electrical generator of claim 1, wherein the structure is mono-crystalline.

5. The electrical generator of claim 3, wherein the nano-structure comprises a nano-rod.

6. The electrical generator of claim 3, wherein the nano-structure comprises a nano-wire.

7. The electrical generator of claim 3, wherein the nano-structure comprises a nano-tube.

8. The electrical generator of claim 3, wherein the nano-structure comprises a nano-ribbon.

9. The electrical generator of claim 3, wherein the nano-structure comprises a nano-belt.

10. The electrical generator of claim 1, wherein the semiconductor piezoelectric structure comprises zinc oxide.

11. The electrical generator of claim 1, wherein the first conductive contact comprises a metal.

12. The electrical generator of claim 1, wherein the semiconductor piezoelectric structure comprises a plurality of nanorods extending upwardly from the first substrate and wherein the first conductive contact comprises an uneven surface disposed parallel to and spaced apart from the first substrate.

13. The electrical generator of claim 12, wherein the uneven surface defines a plurality of corrugations.

14. The electrical generator of claim 12, wherein the uneven surface defines a plurality of nano-bowls that are directed toward the first substrate.

15. The electrical generator of claim 1, wherein the semiconductor piezoelectric structure comprises a plurality of nanorods extending upwardly from the first substrate and wherein the first conductive contact comprises:

a. a conductive blade having an edge that is parallel to the first substrate and transverse to the nanorods; and

b. a mechanism that moves the blade across the plurality of nanorods so as to cause at set of the nanorods to bend and so as to make contact with an end of each of the set of nanorods thereby forming a forward-biased Schottky barrier therebetween.

16. The electrical generator of claim 1, wherein the semiconductor piezoelectric structure comprises a plurality of nanorods extending radially from a core that is capable of rotating about an axis.

17. The electrical generator of claim 16, wherein the first conductive contact is spaced apart from the core in a fixed relationship so that the first end of each of the nanorods moves into contact with the first conductive contact so as to form a forward-biased Schottky barrier as the core rotates.

18. The electrical generator of claim 1, wherein the semiconductor piezoelectric structure comprises a plurality of semiconductor piezoelectric nanorods extending upwardly from the first substrate and wherein the first conductive contact comprises a plurality of conductive nanorods extending downwardly from a second substrate and disposed so that a first end of each of a set of the semiconductor piezoelectric nanorods is adjacent to a first end of each of a set of the conductive nanorods so that as the conductive nanorods vibrate laterally with respect to the semiconductor piezoelectric nanorods, a forward-biased Schottky barrier is formed by contact of at least one conductive nanorod and at least one semiconductor piezoelectric nanorod.

19. The electrical generator of claim 1, wherein the semiconductor piezoelectric structure comprises a plurality of nanorods extending upwardly from the first substrate and wherein the first conductive contact comprises a conductive layer spaced apart from the substrate and in contact with a set of the plurality of nanorods.

20. The electrical generator of claim 19, further comprising a deformable insulating layer disposed between the substrate and the conductive layer.

21. The electrical generator of claim 20, wherein the deformable insulating layer comprises a material that is sufficiently plastic as to allow the nanorods to bend when a predetermined force is applied to the electrical generator.

22. The electrical generator of claim 20, wherein the deformable insulating layer comprises an organic compound.

23. The electrical generator of claim 20, wherein the conductive layer comprises a metal.

24. The electrical generator of claim 23, wherein the metal comprises gold.

25. The electrical generator of claim 20, wherein the conductive layer comprises a conductive polymer.

26. A method of making an electrical generator, comprising the actions of:

a. growing a semiconductor piezoelectric structure from a first substrate; and

b. placing a first conductive contact in a position relative to the semiconductor piezoelectric structure so that when the semiconductor piezoelectric structure bends, the first conductive contact becomes in electrical communication with a portion of the semiconductor piezoelectric structure so as to form a forward-biased Schottky barrier therebetween.

27. The method of claim 26, further comprising the action of electrically coupling the first conductive contact to an electrical load.

28. The method of claim 26, wherein the growing action, comprises the actions of:

a. applying catalyst particles to the first substrate;

b. placing the catalyst particles, the first substrate and a vapor phase precursor into an environment that causes the vapor phase precursor to vaporize and to precipitate on the catalyst particles;

c. removing the substrate from the environment after a predetermined amount of time.

29. The method of claim 26, further comprising the actions of:

a. making the first conductive contact so as to have a planar uneven surface; and

b. placing the first conductive contact parallel to and spaced apart from the first substrate.

30. The method of claim 29, wherein the making action comprises forming a plurality of nano-bowls from a conductive substance.

31. The method of claim 30, wherein the forming action comprises the steps of:

a. placing a plurality of organic spheres onto a surface of a second substrate;

b. applying a metal oxide to the organic spheres, thereby forming a metal oxide shell around the organic spheres;

c. removing a portion of each metal oxide shell and a corresponding portion of each organic sphere; and

d. removing any remaining portion of each organic sphere, thereby leaving a plurality of bowl-shaped structures on the second substrate.

32. A method of making a sheet electrical generator, comprising the actions of:

a. growing a plurality of semiconductor piezoelectric structures upwardly from a substrate;

b. depositing a first deformable layer onto the substrate to a level so that the deformable layer surrounds each of the plurality of semiconductor piezoelectric structures to a predetermined level; and

c. depositing a conductive contact layer above the deformable insulating layer so that the conductive layer is in electrical communication with the plurality of semiconductor piezoelectric structures when a downward force is applied thereto.

33. The method of claim 32, wherein the action of depositing a conductive layer comprises the action of depositing a conductive metal.

34. The method of claim 32, wherein the action of depositing a conductive layer comprises the action of depositing a conductive polymer.

35. The method of claim 32, wherein the action of growing a plurality of semiconductor piezoelectric structures comprises the action of growing a plurality of nanorods.