Graphene growth on a non-hexagonal lattice
A graphene layer is formed on a crystallographic surface having a non-hexagonal symmetry. The crystallographic surface can be a surface of a single crystalline semiconductor carbide layer. The non-hexagonal symmetry surface of the single crystalline semiconductor carbide layer is annealed at an elevated temperature in ultra-high vacuum environment to form the graphene layer. During the anneal, the semiconductor atoms on the non-hexagonal surface of the single crystalline semiconductor carbide layer are evaporated selective to the carbon atoms. As the semiconductor atoms are selectively removed, the carbon concentration on the surface of the semiconductor-carbon alloy layer increases. Despite the non-hexagonal symmetry of the surface of the semiconductor-carbon alloy layer, the remaining carbon atoms can coalesce to form a graphene layer having hexagonal symmetry.
1. A method of forming a graphene layer including at least one graphene monolayer, said method comprising forming a graphene layer by evaporating semiconductor atoms selective to carbon atoms from a crystallographic semiconductor surface having a non-hexagonal symmetry that is different from a symmetry of a (111) plane of any cubic crystal structure.
2. The method of claim 1 , wherein said crystallographic semiconductor surface has a rectangular symmetry.
3. The method of claim 1 , wherein said crystallographic semiconductor surface is a surface of a crystalline semiconductor carbide layer.
4. The method of claim 3 , wherein said crystalline semiconductor carbide layer is a crystalline silicon carbide layer.
5. The method of claim 4 , wherein said crystalline semiconductor carbide layer is a polycrystalline silicon carbide layer having a beta phase and a plurality of (100) crystallographic semiconductor surfaces.
6. The method of claim 4 , wherein said crystalline semiconductor carbide layer is a single crystalline silicon carbide layer having a beta phase and a (100) crystallographic semiconductor surface.
7. The method of claim 3 , wherein said crystalline semiconductor carbide layer is formed directly on a single crystalline semiconductor layer prior to forming said graphene layer.
8. The method of claim 7 , wherein said crystalline semiconductor carbide layer is a single crystalline silicon carbide layer in beta phase having zinc blende structure, and said single crystalline semiconductor layer is a single crystalline silicon layer.
9. The method of claim 8 , wherein said graphene layer is formed directly on a (100) surface of said single crystalline silicon carbide layer in said beta phase.
10. The method of claim 9 , wherein said single crystalline silicon carbide layer is formed directly on a (100) surface of said single crystalline silicon layer.
11. The method of claim 3 , wherein said graphene layer is formed by an anneal that converts a surface layer of said crystalline semiconductor carbide layer into said graphene layer.
12. The method of claim 1 , wherein said non-hexagonal symmetry is selected from cubic symmetry, rectangular symmetry, and tetragonal symmetry.
13. The method of claim 1 , wherein said non-hexagonal symmetry is selected from cubic symmetry and rectangular symmetry.
14. The method of claim 1 , wherein said non-hexagonal symmetry is cubic symmetry.