Double-layer graphene optical modulators and methods of fabrication thereof
This disclosure provides systems, methods, and apparatus related to optical modulators. In one aspect, a device includes a substrate, a first electrically insulating material disposed over the substrate, a first graphene layer and a second graphene layer disposed in the first electrically insulating material and being separated by the first electrically insulating material, and a waveguide disposed on the first electrically insulating material. At least a portion of the second graphene layer overlays at least a portion of the first graphene layer. The waveguide overlays both the first graphene layer and the second graphene layer.
1. A device comprising:
a substrate;
a first electrically insulating material disposed over the substrate;
a first graphene layer and a second graphene layer disposed in the first electrically insulating material and being separated by the first electrically insulating material, a thickness of the first electrically insulating material between the first graphene layer and the second graphene layer being 120 nanometers, at least a portion of the second graphene layer overlaying at least a portion of the first graphene layer; and
a waveguide disposed on the first electrically insulating material, the waveguide overlaying both the first graphene layer and the second graphene layer.
2. The device of claim 1 , wherein the first graphene layer and the second graphene layer each consist of a single layer of carbon atoms.
3. The device of claim 1 , further comprising
a first electrode in contact with the first graphene layer; and
a second electrode in contact with the second graphene layer.
4. The device of claim 3 , wherein the first electrode and the second electrode each comprise a metal.
5. The device of claim 1 , wherein the first electrically insulating material comprises Al 2 O 3 .
6. The device of claim 1 , wherein a thickness of the first electrically insulating material between the substrate and the first graphene layer is about 10 nanometers to 20nanometers.
7. The device of claim 1 , wherein the first graphene layer and the second graphene layer are substantially parallel to each other.
8. The device of claim 1 , wherein a width of the waveguide is substantially parallel to the first graphene layer and the second graphene layer.
9. The device of claim 1 , wherein the waveguide comprises a material selected from a group consisting of silicon, silicon nitride, a chalcogenide glass, and a polymer.
10. The device of claim 1 , wherein a width of the waveguide is about 100 nanometers to 10 microns, wherein a height of the waveguide is about 100 nanometers to 10 microns, and wherein a length of the waveguide is about 1 micron to 1 millimeter.
11. The device of claim 1 , wherein the substrate comprises an insulating material.
12. The device of claim 1 , wherein the substrate comprises a material selected from a group consisting of an oxide, a nitride, and a polymer film.
13. The device of claim 1 , wherein the substrate has a lower index of refraction than the waveguide.
14. A device comprising:
a substrate;
a first electrically insulating material disposed over the substrate;
a first 2-D semiconductor layer and a second 2-D semiconductor layer disposed in the first electrically insulating material and being separated by the first electrically insulating material, a thickness of the first electrically insulating material between the first 2-D semiconductor layer and the second 2-D semiconductor layer being 120 nanometers, at least a portion of the second 2-D semiconductor layer overlaying at least a portion of the first 2-D semiconductor layer; and
a waveguide disposed on the first electrically insulating material, the waveguide overlaying both the first 2-D semiconductor layer and the second 2-D semiconductor layer.
15. The device of claim 14 , wherein the first and the second 2-D semiconductor layers are selected from a group consisting of molybdenum disilicide, black phosphorine, and graphene.
16. (Withdrawn, Currently Amended) A method comprising:
(a) depositing a first electrically insulating material over a substrate;
(b) depositing a first graphene layer on the first electrically insulating material;
(c) depositing a first electrode on a portion of the first graphene layer;
(d) depositing the first electrically insulating material on the first graphene layer;
(e) after operation (d), depositing a second graphene layer on the first electrically insulating material;
(f) depositing a second electrode on a portion of the second graphene layer;
(g) depositing the first electrically insulating material on the second graphene layer; and
(h) after operation (g), forming a waveguide on the first electrically insulating material, a resulting device comprising:
the substrate;
the first electrically insulating material disposed over the substrate;
the first graphene layer and the second graphene layer disposed in the first electrically insulating material and being separated by the first electrically insulating material, a thickness of the first electrically insulating material between the first graphene layer and the second graphene layer being 120 nanometers, at least a portion of the second graphene layer overlaying at least a portion of the first graphene layer; and
the waveguide disposed on the first electrically insulating material, the waveguide overlaying both the first graphene layer and the second graphene layer.
17. The method of claim 16 , further comprising:
after operation (h), annealing the substrate and the depositions thereon at about 200° C. to 500° C. for about 5 minutes to 15 minutes.
18. The method of claim 16 , wherein the waveguide overlays both the first graphene layer and the second graphene layer.