GRAPHENE WINDOWS, METHODS FOR MAKING SAME, AND DEVICES CONTAINING SAME

1 . A method comprising:

a. selecting a metal foil having a first face and a second face;

b. forming a graphene-modified foil comprising the step of growing a first layer of graphene on the first face of the metal foil, wherein

i. the graphene-modified foil has a first face and a second face, and

ii the first layer of graphene is at the first face of the graphene-modified foil;

c. patterning the second face of the graphene-modified foil with a polymer, wherein the second face of the graphene-modified foil has an exposed region;

d. etching the second face of the graphene-modified foil in the exposed region until exposing the first layer of graphene, wherein a graphene window is formed and wherein the step of etching comprises

i. a first etching process of etching the metal foil a first distance with a first etchant solution, wherein the first distance is less than the distance needed to etch the metal foil to expose the first layer of graphene, and

ii. a second etching process of etching the metal foil a second distance with a second etchant solution thereby exposing the first layer of graphene, wherein the first etchant solution and the second etchant solution are different.

2 . The method of claim 1 , wherein the first distance is greater than the second distance.

3 . The method of claim 1 , wherein the first distance is at least 90% of the combined distance of the first distance and the second distance.

4 . The method of claim 1 , wherein the first etchant solution is an isotropic etchant solution.

5 . The method of claim 1 , wherein the first etchant solution comprises iron(III) chloride.

6 . The method of claim 1 , wherein the first etchant solution is an iron(III) chloride solution having a concentration of at least 500 mM iron(III) chloride in the iron(III) chloride solution.

7 . The method of claim 1 , wherein the second etchant solution is an anisotropic etchant solution.

8 . The method of claim 1 , wherein the second etchant solution comprises ammonium persulfate.

9 . The method of claim 8 , wherein the first etchant solution comprises iron(III) chloride.

10 . The method of claim 1 , wherein the second etchant solution is an ammonium persulfate solution having a concentration of at least 50 mM ammonium persulfate in the ammonium persulfate solution.

11 . The method of claim 1 , wherein the second etchant solution is an isotropic etchant solution and the second etching process is a more gentle etching process as as compared to the first etching process.

12 . The method of claim 1 , wherein the step of etching further comprises rinsing the metal foil with DI water between the first etching process and the second etching process.

13 . The method of claim 1 , wherein the step of etching further comprises rinsing the metal foil with DI water after the second etching process.

14 . The method of claim 1 , wherein the metal of the metal foil is Cu.

15 . The method of claim 1 , wherein the step of forming the graphene-modified foil further comprises the step of growing a second layer of graphene on the second face of the metal foil.

16 . A method comprising:

a. selecting a metal foil having a first face and a second face;

b. forming a graphene-modified foil comprising the step of growing a first layer of graphene on the first face of the metal foil, wherein

i. the graphene-modified foil has a first face and a second face, and

ii the first layer of graphene is at the first face of the graphene-modified foil;

c. patterning the second face of the graphene-modified foil with a polymer, wherein the second face of the graphene-modified foil has an exposed region;

d. etching the second face of the graphene-modified foil in the exposed region until exposing the first layer of graphene, wherein a graphene window is formed, and wherein the step of etching comprises

i. a first etching process of etching the metal foil a first distance with an isotropic etchant solution, wherein the first etching process is stopped before exposing the first layer of graphene, and

ii. a second etching process of etching the metal foil a second distance with a second etchant solution to expose the first layer of graphene, wherein

(A) the second etchant solution is different from the isotropic etchant solution and

(B) the second etchant process is a more gentle etching process as compared to the first etching process.

17 . The method of claim 16 , wherein the second etchant solution is an anistropic etchant solution.

18 . The method of claim 17 , wherein

i. the isotropic etchant solution comprises iron(III) chloride,

ii. the anisotropic etchant solution comprises ammonium persulfate; and

iii. the first distance is greater than the second distance.

19 . The method of claim 18 , wherein

i. the isotropic etchant solution is an iron(III) chloride solution having a concentration of at least 500 mM iron(III) chloride in the solution,

ii. the anisotropic etchant solution is an ammonium persulfate solution having a concentration of at least 50 mM ammonium persulfate in the solution, and

iii. the first distance is at least 90% of the combined distance of the first distance and the second distance.

20 . The method of claim 16 , wherein the step of forming the graphene-modified foil further comprises the step of growing a second layer of graphene on the second face of the metal foil.