Large area deposition and doping of graphene, and products including the same
View Patent ↗Certain example embodiments of this invention relate to the use of graphene as a transparent conductive coating (TCC). In certain example embodiments, graphene thin films grown on large areas hetero-epitaxially, e.g., on a catalyst thin film, from a hydrocarbon gas (such as, for example, C 2 H 2 , CH 4 , or the like). The graphene thin films of certain example embodiments may be doped or undoped. In certain example embodiments, graphene thin films, once formed, may be lifted off of their carrier substrates and transferred to receiving substrates, e.g., for inclusion in an intermediate or final product. Graphene grown, lifted, and transferred in this way may exhibit low sheet resistances (e.g., less than 150 ohms/square and lower when doped) and high transmission values (e.g., at least in the visible and infrared spectra).
1. A method of making a doped graphene thin film, the method comprising:
hetero-epitaxially growing an intermediate graphene thin film on a catalyst thin film, the catalyst thin film having a substantially single-orientation large-grain crystal structure;
doping the intermediate graphene thin film with n-type or p-type dopants in making the doped graphene thin film,
wherein the doped graphene thin film has a sheet resistance less than 150 ohms/square.
2. The method of claim 1 , wherein the doping of the intermediate graphene thin film comprises:
exposing the intermediate graphene thin film to a doping gas comprising a material to be used as the dopant;
exciting a plasma within a chamber containing the intermediate graphene thin film and the doping gas; and
ion beam implanting the dopant in the intermediate graphene thin film using the material in the doping gas.
3. The method of claim 2 , wherein the ion beam power is 10-200 eV.
4. The method of claim 2 , wherein the ion beam power is 20-40 eV.
5. The method of claim 1 , wherein the doping of the intermediate graphene thin film comprises:
providing a target receiving substrate including solid-state dopants therein, the target receiving substrate including dopants therein by virtue of a melting process used to fabricate the target receiving substrate; and
allowing the solid-state dopants in the target receiving substrate to migrate into the intermediate graphene thin film by thermal diffusion.
6. The method of claim 5 , wherein the target receiving substrate includes 1-10 atomic weight percent dopant material.
7. The method of claim 1 , wherein the doping of the intermediate graphene thin film comprises:
providing a target receiving substrate including solid-state dopants therein, the target receiving substrate including dopants therein by virtue of ion beam implantation; and
allowing the solid-state dopants in the target receiving substrate to migrate into the intermediate graphene thin film by thermal diffusion.
8. The method of claim 7 , wherein the ion beam implantation is performed at a power level of 10-1000 eV.
9. The method of claim 1 , wherein the doping of the intermediate graphene thin film comprises:
providing a target receiving substrate having at least one thin film coating disposed thereon, the thin film coating including solid-state dopants therein; and
allowing the solid-state dopants in the at least one thin film formed on the target receiving substrate to migrate into the intermediate graphene thin film by thermal diffusion.
10. The method of claim 1 , wherein the doping of the intermediate graphene thin film comprises:
pre-implanting solid state dopants in the catalyst thin film; and
allowing the solid-state dopants in the catalyst thin film to migrate into the intermediate graphene thin film by thermal diffusion.
11. The method of claim 10 , wherein the thermal diffusion occurs during the deposition of the intermediate graphene thin film.
12. The method of claim 10 , wherein the catalyst thin film includes 1-5% solid-state dopant atoms in its bulk.
13. The method of claim 12 , wherein the catalyst thin film comprises nickel.
14. The method of claim 1 , wherein the doped graphene thin film is doped with any one or more of: nitrogen, boron, phosphorous, fluorine, lithium, potassium, and sulfur.
15. The method of claim 1 , wherein the doped graphene thin film has a sheet resistance of 10-20 ohms/square.
16. A method of making a coated article comprising a doped graphene thin film supported by a substrate, the method comprising:
hetero-epitaxially growing an intermediate graphene thin film on a catalyst thin film, the catalyst thin film having a substantially single-orientation large-grain crystal structure, the intermediate graphene thin film being dopable with n-type and p-type dopants; and
doping the intermediate graphene thin film with one of n-type and p-type dopants in making the doped graphene thin film.
17. The method of claim 16 , wherein the doped graphene thin film includes p-type dopants.
18. A method of making a coated article comprising a doped graphene thin film supported by a substrate, the method comprising:
hetero-epitaxially growing an intermediate graphene thin film on a catalyst thin film, the catalyst thin film having a substantially single-orientation large-grain crystal structure, the intermediate graphene thin film being dopable with n-type and p-type dopants; and
causing one of n-type and p-type solid-state dopants from a source below the intermediate graphene thin film to migrate into the intermediate graphene thin film, by thermal diffusion, in making the doped graphene thin film.
19. The method of claim 18 , wherein the doped graphene thin film has a sheet resistance less than 150 ohms/square.