Multilayer graphene structures with enhanced mechanical properties resulting from deterministic control of interlayer twist angles and chemical functionalization
An article of manufacture includes a first graphene layer, a second graphene layer over the first graphene layer, the second graphene layer oriented at a first interlayer twist angle with respect to the first graphene layer and bonded by interlayer covalent bonds to the first graphene layer, and a third graphene layer over the second graphene layer, the third graphene layer oriented at a second interlayer twist angle with respect to the second graphene layer and bonded by interlayer covalent bonds to the second graphene layer. A multi-layer graphene article includes at least three graphene layers, each graphene layer being oriented at an interlayer twist angle with respect to an adjacent graphene layer and bonded by interlayer covalent bonds to the adjacent graphene layer.
1. A method of making an article, comprising:
orienting a first graphene layer at a first interlayer twist angle with respect to a second graphene layer;
bonding the second graphene layer to the first graphene layer by interlayer covalent sp 3 bonds;
orienting a third graphene layer at a second interlayer twist angle with respect to the second graphene layer; and
bonding the third graphene layer to the second graphene layer by interlayer covalent sp 3 bonds.
2. The method of claim 1 , wherein the method comprises:
a) growing the first graphene layer on a silicon carbide wafer;
b) exfoliating the first graphene layer onto a first transfer layer;
c) disposing the first graphene layer and first transfer layer onto a host substrate, so that the first graphene layer is in contact with the host substrate surface;
d) removing the first transfer layer;
e) growing the second graphene layer on a silicon carbide wafer;
f) exfoliating the second graphene layer onto a second transfer layer;
g) disposing the second graphene layer and second transfer layer over the first graphene layer at the first interlayer twist angle with respect to the first graphene layer, so that the second graphene layer is in contact with the first graphene layer;
h) removing the second transfer layer;
i) covalently bonding the first and second graphene layers, the bonding involving a fraction of carbon atoms of each of the first and second graphene layers;
j) growing the third graphene layer on a silicon carbide wafer;
k) exfoliating the third graphene layer onto a third transfer layer;
l) disposing the third graphene layer and third transfer layer over the second graphene layer at the second interlayer twist angle with respect to the second graphene layer, so that the third graphene layer is in contact with the second graphene layer;
m) removing the third transfer layer; and
n) covalently bonding the third and second graphene layers, the bonding involving a fraction of carbon atoms of each of the second, and third graphene layers.
3. The method of claim 1 , wherein the first and second interlayer twist angles are each separately in a range of between 0° and about 16°.
4. The method of claim 1 , wherein the first and second interlayer twist angles are each separately in a range of between about 44° and 60°.
5. The method of claim 1 , wherein the covalent bonding includes chemical functionalization of the graphene layers.
6. The method of claim 5 , wherein chemical functionalization includes hydrogenation.
7. The method of claim 6 , wherein hydrogenation includes using a hydrogen plasma.
8. The method of claim 5 , wherein chemical functionalization includes fluorination.
9. The method of claim 8 , wherein fluorination includes using a fluorine plasma.