Graphene grown substrate and electronic/photonic integrated circuits using same
A graphene-on-oxide substrate according to the present invention includes: a substrate having a metal oxide layer formed on its surface; and, formed on the metal oxide layer, a graphene layer including at least one atomic layer of the graphene. The graphene layer is grown generally parallel to the surface of the metal oxide layer, and the inter-atomic-layer distance between the graphene atomic layer adjacent to the surface of the metal oxide layer and the surface atomic layer of the metal oxide layer is 0.34 nm or less. Preferably, the arithmetic mean surface roughness Ra of the metal oxide layer is 1 nm or less.
1. A graphene-on-oxide substrate, comprising:
a substrate having a metal oxide layer formed on its surface; and
a graphene layer formed directly on the metal oxide layer, the graphene layer including at least one atomic layer of graphene, the graphene layer being grown directly on and parallel to a surface of the metal oxide layer, the inter-atomic-layer distance between the graphene atomic layer adjacent to the surface of the metal oxide layer and a surface atomic layer of the metal oxide layer being 0.34 nm or less,
wherein the metal oxide layer contains aluminum.
2. The graphene-on-oxide substrate according to claim 1 , wherein the arithmetic mean surface roughness Ra of the metal oxide layer is 1 nm or less.
3. The graphene-on-oxide substrate according to claim 1 , wherein the maximum surface height Rz of the metal oxide layer is 10 nm or less.
4. The graphene-on-oxide substrate according to claim 1 , wherein the graphene layer is formed of graphene crystal grains, and the average grain size of the graphene crystal grains is 5 nm or more.
5. The graphene-on-oxide substrate according to claim 1 , wherein the metal oxide layer is polycrystalline, and the average thickness of the polycrystalline metal oxide layer is 10 nm or more and 500 nm or less.
6. The graphene-on-oxide substrate according to claim 1 , wherein the substrate is a single crystalline metal oxide substrate.
7. The graphene-on-oxide substrate according to claim 6 , wherein the single crystalline metal oxide substrate is a single crystalline α-alumina c-plane substrate.
8. The graphene-on-oxide substrate according to claim 1 , having an area of 20 cm 2 or more.
9. An electro-optical integrated circuit formed in the graphene-on-oxide substrate according to claim 1 .
10. The electro-optical integrated circuit according to claim 9 , wherein a channel of a field effect transistor, an optical emitting device, an optical receiving device and circuit wiring are formed in the graphene layer of the graphene-on-oxide substrate.
11. The graphene-on-oxide substrate according to claim 1 , wherein the inter-atomic-layer distance between the graphene atomic layer adjacent to the surface of the metal oxide layer and the surface atomic layer of the metal oxide layer is 0.30 to 0.34 nm.
12. The graphene-on-oxide substrate according to claim 1 , wherein the metal oxide layer underlies the graphene layer and the metal oxide layer is disposed between the substrate and the graphene layer.