Graphene-based Multi-Modal Sensors

• US 20170102334A1
• Filed: 10/07/2016
• Published: 04/13/2017
• Est. Priority Date: 10/07/2015
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Zaretski, Aliaksandr, Lipomi, Darren J., Savtchenko, Alex, Molokanova, Elena, Mercola, Mark
• Granted Patent: US 9,863,885 B2
• Time in Patent Office: Days
• CPC Class Codes: C23C 14/024 Deposition of sublayers, e.g. to promote adhesion of the coating C23C14/027 takes precedence
• CPC Class Codes: C23C 14/04 Coating on selected surface areas, e.g. using masks
• CPC Class Codes: C23C 14/18 on other inorganic substrates
• CPC Class Codes: C23C 14/30 by electron bombardment
• CPC Class Codes: C23C 16/01 on temporary substrates, e.g. substrates subsequently removed by etching
• CPC Class Codes: C23C 16/0227 by cleaning or etching
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01N 2021/651 Cuvettes therefore
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G01N 27/028 Circuits therefor measuring impedance per se G01R27/02

Abstract

A method for fabricating a composite film structure, the method includes determining a desired morphology for a metallic layer of the composite film structure, selecting a first metal substrate based on the determining, transferring a graphene layer onto the first metal substrate, depositing the metallic layer on the graphene layer to achieve the desired morphology, and removing the first metal substrate from the graphene and the deposited metallic layer to form the composite film structure. A surface energy difference between the first metal substrate and the deposited metallic layer results in the desired morphology of the metallic layer.

Claims

1. A method for fabricating a composite film structure, the method comprising:

determining a desired morphology for a metallic layer of the composite film structure;

selecting a first metal substrate based on the determining;

transferring a graphene layer onto the first metal substrate;

depositing the metallic layer on the graphene layer to achieve the desired morphology; and

removing the first metal substrate from the graphene and the deposited metallic layer to form the composite film structure, wherein a surface energy difference between the first metal substrate and the deposited metallic layer results in the desired morphology of the metallic layer.

2. The method of claim 1, wherein the desired morphology comprises nanoislands.

3. The method of claim 2, wherein a distance between edges of nanoislands in the metallic layer is on the order of molecular dimensions.

4. The method of claim 1, wherein depositing the metallic layer comprises deposition of evaporated flux of metallic atoms.

5. The method of claim 4, wherein the evaporated flux of metallic atoms self-assemble to yield the desired morphology.

6. The method of claim 4, where in the evaporated flux of metallic atoms are produced by electron beam evaporation, thermal evaporation, or sputtering.

7. The method of claim 1, wherein transferring the graphene layer onto the first metal substrate comprises exfoliating the graphene grown on a second metal substrate and placing the graphene layer onto the first metal substrate;

and wherein the graphene comprises a single layer of graphene.

8. The method of claim 7, wherein the graphene is grown on the second metal substrate using chemical vapor deposition.

9. The method of claim 1, wherein the first metal substrate comprises a transition metal.

10. The method of claim 9, wherein the transition metal comprises gold, silver, or nickel.

11. A method of forming a substrate for surface-enhanced Raman scattering, the method comprising:

depositing a graphene layer on a first metal substrate;

depositing a plurality of metallic nanoislands on the graphene layer;

removing the first metal substrate from the graphene and the deposited plurality of metallic nanoislands to form the substrate for surface-enhanced Raman scattering.

12. A method of performing surface-enhanced Raman scattering of an analyte, the method comprising:

forming a substrate for surface-enhanced Raman scattering according to the method of claim 11;

transferring the substrate on an optical fiber;

coating the analyte on the substrate; and

recording surface-enhanced Raman scattering signals from the analyte.

13. A method of performing surface-enhanced Raman scattering of an analyte, the method comprising:

forming a substrate for surface-enhanced Raman scattering according to the method of claim 11;

transferring the substrate on an optical fiber;

placing the substrate into the analyte; and

recording surface-enhanced Raman scattering signals from the analyte.

14. The method of claim 12, wherein the plurality of metallic nanoislands comprises a plasmonically active metal.

15. The method of claim 14, wherein the plasmatically active metal comprises copper, silver, palladium, gold, or platinum nanoislands.

16. A strain sensor, the strain senor comprising:

a graphene layer;

a metallic layer on the graphene layer; and

a polymer on the graphene layer and the metallic layer;

wherein a piezoresistance of the strain sensor allows strain spanning four orders of magnitude to be detected.

17. The strain sensor of claim 16, wherein the metallic layer comprises palladium, the first metal substrate comprises copper and the polymer comprises polydimethylsiloxane.

18. The strain sensor of claim 16, wherein the graphene layer is configured to suppress crack propagation through the metallic layer.

19. The strain sensor of claim 16, wherein a gauge factor at 1% strain of the strain sensor is at least 1300.

20. A system for measuring mechanical movements in a biological sample, the system comprising:

a chamber;

a composite film structure on which a biological sample is disposed, the composite film structure comprising a metallic layer in contact with a graphene layer, and a polymer layer in contact with either the metallic layer or the graphene layer;

electrical connections for electrically accessing the composite film structure; and

a central opening in the chamber, the central opening configured to receive the biological sample disposed on the composite film structure, wherein the biological sample comprises cultured cells or tissues, wherein the metallic layer comprises a plurality of metallic nanoislands.

21. The system of claim 20, wherein the polymer layer is in contact with the metallic layer and the biological sample is grown directly on the graphene layer.

22. The system of claim 20, wherein the polymer layer is in contact with the graphene layer and the biological sample is grown directly on the metallic layer.

23. The system of claim 20, wherein the system is configured to provide an amplitude and temporal profile of the mechanical movements of the cultured cells.

24. The system of claim 20, wherein the system is configured to provide an electrical impedance profile associated with an activity of the cultured cells.

25. The system of claim 20, further comprising a plurality of electrodes, wherein a first electrode is located on one side of the cultured cells, and a second electrode is located on an opposite of the cultured cells.

26. The system of claim 20, further comprises a second pair of substrates configured to sandwich the composite film structure bearing the cultured cells.

27. The system of claim 20, wherein the system is configured to provide a profile of cellular contractility by an optical observation of a change in distance between metallic nanoislands in the plurality of metallic nanoislands.

28. The system of claim 20, wherein the system is configured to provide the cellular membrane potential profile due to an activity of the cultured cells.

29. The system of claim 20, wherein the system is configured to provide a profile of cellular contractility by an optical observation of a change in distance between metallic nanoislands in the plurality of metallic nanoislands.

30. The system of claim 20, wherein the system is configured to provide Raman scattering data from the cultured cells.