Process for producing two-dimensional nanomaterials
View Patent ↗The present invention provides a process for producing a two-dimensional nanomaterial by chemical vapor deposition (CVD), the process comprising contacting a substrate in a reaction chamber with a first flow which contains hydrogen and a second flow which contains a precursor for said material, wherein the contacting takes place under conditions such that the precursor reacts in the chamber to form said material on a surface of the substrate, wherein the ratio of the flow rate of the first flow to the flow rate of the second flow is at least 5:1. Two-dimensional nanomaterials obtainable by said process are also provided, as well as devices comprising said nanomaterials.
1. A process for producing a two-dimensional nanomaterial by chemical vapour deposition (CVD), the process comprising contacting a substrate in a reaction chamber with a first flow which contains hydrogen and a second flow which contains a precursor for said material, wherein the contacting takes place under conditions such that the precursor reacts in the chamber to form said material on a surface of the substrate, wherein the ratio of the flow rate of the first flow to the flow rate of the second flow is at least 10:1, wherein the two-dimensional nanomaterial is graphene and the precursor is a carbon precursor, and wherein the substrate is a copper substrate and at least a portion of said surface of the substrate has a crystallographic orientation of (101), (001) or (111).
2. A process according to claim 1 , wherein the contacting takes place under a pressure within the reaction chamber of below 1 bar.
3. A process according to claim 1 , wherein at least a portion of said surface of the substrate has a crystallographic orientation of (101).
4. A process according to claim 1 , wherein said surface of the substrate is substantially fully oriented in a single crystallographic orientation.
5. A process according to claim 1 , wherein:
(i) the flow rate of the first flow is 5 sccm or more; and/or
(ii) the flow rate of the second flow is 20 sccm or less.
6. A process according to claim 1 , wherein:
(i) the temperature within the reaction chamber is from about 800° C. to about 1050° C.; and/or
(ii) the pressure within the reaction chamber is less than 50 Torr.
7. A process according to claim 1 , wherein the substrate is pre-treated with hydrogen before contacting the substrate with the second flow.
8. A process according to claim 1 , wherein the carbon precursor is methane.
9. A process according to claim 1 , wherein:
(i) the graphene produced by the process is substantially monolayer or bilayer graphene; and/or
(ii) the geometry of one or more edges of the graphene is substantially zigzag or substantially armchair.
10. A process according to claim 1 , wherein at least one edge of the two-dimensional nanomaterial is oriented substantially parallel to a <110> direction on a crystallographic orientation on said surface of the substrate.
11. A process according to claim 1 , wherein the process further comprises forming a product comprising the two-dimensional nanomaterial.
12. A process according to claim 1 , wherein the two-dimensional nanomaterial is produced by atmospheric-pressure chemical vapour deposition or low-pressure chemical vapour deposition.
13. A process according to claim 1 , wherein the contacting takes place under a pressure within the reaction chamber of about 1 bar or less than about 1 bar.