Use of noble metal nanoparticles as light absorbers and heat generators in thermal photodetectors, sensors and microelectromechanical devices

• US 8,618,481 B2
• Filed: 11/20/2009
• Issued: 12/31/2013
• Est. Priority Date: 11/21/2008
• Status: Active Grant

• Current Assignee: THE GOVERNMENT OF THE UNITED STATES OF AMERICA, AS REPRESENTED BY THE SECRETARY OF COMMERCE
• Original Assignee: Babak Nikoobakht
• Inventors: Nikoobakht, Babak
• Primary Examiner(s): Bryant, Casey
• Application Number:
  US12/623,318
• Publication Number:
  US 20100127172A1
• Time in Patent Office: 1,502 Days
• Field of Search: 250/338.1, 250/338.4
• US Class Current: 250/338.1
• CPC Class Codes: B81B 2201/0278 Temperature sensors
• CPC Class Codes: B81B 3/0081 Thermal properties
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/023 Particular leg structure or construction or shape; Nanotubes
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0853 having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid

Abstract

This disclosure provides methods to integrate heat generating nanoparticles to microelectromechanical (MEMs) and photonic devices such as microbolometers and thermopiles for better photodetection and electrical energy generation. Nanoparticles include noble metal and semiconductor nanocrystals of different shapes, as light sensing and heat generating materials.

Claims

1. A microbolometer or thermopile comprising a substrate and a light detector, wherein the light detector comprises ordered arrays of nanomaterial embedded in a matrix that enhances light absorption and releases heat for enhanced sensitivity.

2. The device according to claim 1, wherein the nanomaterial comprises nanorods, nanospheres or nanocrystals.

3. The device of claim 2 wherein the nanomaterial comprises aligned nanorods.

4. The device of claim 3 wherein the aligned nanorods are gold nanorods.

5. The device of claim 4 wherein the gold nanorods have an aspect ratio greater than two.

6. The device of anyone of claims 1-5 wherein the substrate is a monocrystalline silicon wafer or an organic thin film.

7. The device of claim 4 or 5 wherein spacing between adjacent nanorods is between 10 and 50 nm.

8. The microbolometer of claim 1 having a size of 3-50 microns square.

9. In a thermal photodetector comprising a mircrobolometer or thermopile, the improvement wherein the mircrobolomeer or thermopile is in accordance with claim 1.

10. In a thermal imaging camera or an infra-red camera comprising a thermal photodetector, the improvement wherein the thermal photodetector is in accordance with claim 9.

20. The microbolometer of claim 8 having a size of 3-50 microns square.

11. A method of integrating a nanomaterial in an electro-optical device for enhanced sensitivity, the method comprising:

providing a substrate;

forming on the substrate a conductive matrix which sandwiches an ordered array of nanomaterials, and

connecting the matrix and the ordered array of nanomaterials to two separate conductive layers to form an electro-optical device,

wherein the plurality of ordered arrays of nanomaterials operably change the conductivity of the matrix.

12. The method according, to claim 11, wherein the nanomaterial is homogenously integrated in planar form as a monolayer.

13. The method of claim 11, wherein the nanomaterial is hormogenously integrated in a planar form as a multilayer.

14. The method of any one of claim 12 or 13, wherein the nanomaterial comprises nanorods, nanospheres, nanoshells or nanocrystals.

15. The method of claim 14 wherein the nanomateriai comprises aligned nanords.

16. The method of claim 15 wherein the aligned nanorods are gold nanorods.

17. The method of claim 16 wherein the gold nanorods have an aspect ratio greater than two.

18. The method of claims 11 wherein the substrate is a monocrystalline silicon wafer or an organic thin film.

19. The method of claim 16 wherein spacing between adjacent nanorods is between 10 and 50 nm.

21. In a thermal photodetector comprising a mircrobolometer or thermopile, the improvement wherein the mircrobolometer or thermopile is in accordance with claim 11.

22. In a thermal imaging camera or an infra-red camera comprising a thermal photodetector, the improvement wherein the thermal photodetector is in accordance with claim 21.