Patterned Functionalization of Nanomechanical Resonators for Chemical Sensing

• US 20100086735A1
• Filed: 10/01/2009
• Published: 04/08/2010
• Est. Priority Date: 10/03/2008
• Status: Abandoned Application

• Current Assignee: Navy The USA As Represented By The Secretary of The
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Baldwin, Jeffrey W., Pate, Bradford B., Zalalutdinov, Maxim K., Houston, Brian H.
• Application Number:
  US12/571,830
• Publication Number:
  US 20100086735A1
• Time in Patent Office: Days
• US Class Current: 428/138
• CPC Class Codes: B81B 2201/0271 Resonators; ultrasonic resonators
• CPC Class Codes: B81C 1/00206 Processes for functionalising a surface, e.g. provide the surface with specific mechanical, chemical or biological properties
• CPC Class Codes: G01N 2291/0257 with a layer containing at least one organic compound
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: H03H 9/02259 Driving or detection means
• CPC Class Codes: H03H 9/2405 of microelectro-mechanical resonators
• CPC Class Codes: Y10T 428/24331 including nonapertured component

Abstract

A method of functionalizing a nanomechanical resonator involving providing a wafer with a thin film layer on a sacrificial layer, suspending freely a resonator on the wafer, coating the resonator with a liquid containing a terminal allyl group, placing a quartz-mask on the wafer, trapping the liquid between the mask and the wafer, initiating a reaction of the terminal allyl with photo-induced electrons, rinsing the wafer, and drying the wafer. The liquid can be 2-allyl hexafluoroisopropanol or another liquid that has an effective sorbent group for DMMP or DNT. The initiating can be performed via a deep UV source selected from a Hg arc, Xe arc, or DUV laser. The method can further include incorporating narrow gaps of from about 50 to about 300 nm in the resonator.

Claims

1. A method of functionalizing a nanomechanical resonator comprising:

providing a wafer with a thin film layer on a sacrificial layer;

suspending freely a resonator on the wafer;

coating the resonator with a liquid containing a terminal allyl group;

placing a quartz-mask on the wafer;

trapping the liquid between the mask and the wafer;

initiating a reaction of the terminal allyl with photo-induced electrons;

rinsing the wafer; and

drying the wafer.

2. The method of claim 1 wherein the liquid is 2-allyl hexafluoroisopropanol.

3. The method of claim 1 wherein the liquid has an effective sorbent group for DMMP or DNT.

4. The method of claim 1 wherein said initiating is performed via a deep UV source.

5. The method of claim 4 wherein said deep UV source is one selected from the group consisting of Hg arc, Xe arc, and DUV laser.

6. The method of claim 4 wherein the electrons of the step of initiating a reaction of the terminal allyl with electrons are electrons that are generated at the surface of the resonator due to the deep UV exposure.

7. The method of claim 1 wherein said step of rinsing comprises using isopropanol.

8. The method of claim 1 wherein said step of drying comprises using a critical point dryer.

9. The method of claim 1 wherein the functionalizing results in about 50% coverage by a monolayer.

10. The method of claim 4 wherein the step via a deep UV source includes about a 12 hour exposure time with a Xe lamp.

11. The method of claim 1 further including incorporating narrow gaps of from about 50 to about 300 nm in the resonator.

12. The method of claim 11 wherein the functionalized nanomechanical resonator has a sensitivity of about 10⁻

16 g.

13. The method of claim 1 wherein the wafer with a thin film layer on a sacrificial layer is one selected from the group consisting of silicon, diamond, polysilicon, and germanium on silicon oxide.

14. A method of functionalizing a nanomechanical resonator comprising:

providing a wafer wherein the wafer is one selected from the group consisting of silicon on silicon oxide, diamond on silicon oxide, polysilicon on silicon oxide, and germanium on silicon oxide;

suspending freely a resonator on the wafer;

coating the resonator with a liquid wherein the liquid contains at least one functional group hexafluoroisopropanol;

placing a quartz-mask on the wafer;

trapping the liquid between the mask and the wafer; and

initiating a reaction of the functional group hexafluoroisopropanol with photo-induced electrons.

15. The method of claim 14 wherein the liquid has an effective sorbent group for DMMP or DNT.

16. The method of claim 15 wherein said initiating is performed via a deep UV source and wherein said deep UV source is one selected from the group consisting of Hg arc, Xe arc, and DUV laser.

17. The method of claim 16 wherein the electrons of the step of initiating a reaction of the functional group hexafluoroisopropanol with electrons are electrons that are generated at the surface of the resonator due to the deep UV exposure.

18. The method of claim 17 wherein the functionalizing results in about 50% coverage by a monolayer.

19. The method of claim 18 further including incorporating narrow gaps of from about 50 to about 300 nm in the resonator.

20. A functionalizing nanomechanical resonator comprising:

a wafer wherein the wafer is one selected from the group consisting of silicon on silicon oxide, diamond on silicon oxide, polysilicon on silicon oxide, and germanium on silicon oxide;

a freely suspended resonator on the wafer;

wherein the resonator is coated with a liquid wherein the liquid contains at least one functional group hexafluoroisopropanol;

wherein the resonator is functionalized by initiating a reaction of the functional group hexafluoroisopropanol with photo-induced electrons and results in about 50% coverage by a monolayer;

wherein the liquid has an effective sorbent group for DMMP or DNT; and

wherein narrow gaps of from about 50 to about 300 nm are incorporated in the resonator.