Plasmonic diamond films and related methods

1. A method of forming a plasmonic diamond film, the method comprising:

(a) forming a first layer of diamond on a substrate;

(b) depositing a layer of a metal on a surface of the first layer of diamond to form an as-deposited layer of metal;

(c) exposing the as-deposited layer of metal to a plasma treatment to convert the as-deposited layer of metal to a plurality of discrete regions of the metal on the surface of the first layer of diamond; and

(d) forming a second layer of diamond on the plurality of discrete regions of metal to form the plasmonic diamond film comprising a plurality of plasmonic nanoparticles.

2. The method of claim 1 , wherein the second layer encapsulates the plurality of discrete regions of the metal to provide the plurality of plasmonic nanoparticles embedded within a continuous diamond matrix.

3. The method of claim 1 , wherein the second layer encapsulates the plurality of discrete regions of the metal to provide the plurality of plasmonic nanoparticles as core-shell plasmonic nanoparticles distributed on the surface of the first layer of diamond, each core-shell plasmonic nanoparticle comprising a core of the metal and a diamond shell thereover.

4. The method of claim 3 , wherein the surface of the first layer of diamond between the core-shell plasmonic nanoparticles is uncoated by the second layer of diamond.

5. The method of claim 1 , wherein the diamond of the first layer of diamond is hydrogen-terminated diamond.

6. The method of claim 1 , wherein the diamond of the first and second layers of diamond is polycrystalline diamond.

7. The method of claim 1 , wherein the metal is selected from Cu, Ag, Au, Pt, Al, Co, Pd, and combinations thereof.

8. The method of claim 1 , wherein the metal is selected from Ag, Au, Cu, Al, and combinations thereof.

9. The method of claim 8 , wherein the plurality of plasmonic nanoparticles have an average diameter of less than 100 nm.

10. The method of claim 1 , wherein the as-deposited layer of metal has an average thickness in the range of from 1 nm to 100 nm.

11. The method of claim 1 , wherein the plasma treatment in step (c) is an H 2 plasma treatment.

12. The method of claim 1 , wherein the as-deposited layer of metal is seeded with diamond prior to the plasma treatment in step (c).

13. The method of claim 1 , further comprising repeating steps (b)-(d) of the method one or more times to form a multi-layer plasmonic diamond structure.

14. The method of claim 1 , wherein the metal is Ag and the second layer encapsulates the plurality of discrete regions of Ag to provide the plurality of plasmonic nanoparticles as core-shell plasmonic nanoparticles distributed on the surface of the first layer of diamond, each core-shell plasmonic nanoparticle comprising an Ag core and a diamond shell thereover.

15. The method of claim 14 , wherein the surface of the first layer of diamond between the core-shell plasmonic nanoparticles is uncoated by the second layer of diamond.

16. The method of claim 14 , wherein the diamond of the first layer of diamond is hydrogen-terminated diamond.

17. The method of claim 14 , wherein the diamond of the shell is polycrystalline diamond.

18. The method of claim 14 , wherein the as-deposited layer of Ag has an average thickness in the range of from 1 nm to 100 nm and the diamond shells have an average thickness in the range of from 1 nm to 100 nm.

19. The method of claim 14 , wherein the plasma treatment is an H 2 plasma treatment.

20. The method of claim 14 , wherein Ag cores of the core-shell plasmonic nanoparticles have an average diameter of less than 100 nm.