Formation of a graphene layer on a large substrate
A single crystalline silicon carbide layer can be grown on a single crystalline sapphire substrate. Subsequently, a graphene layer can be formed by conversion of a surface layer of the single crystalline silicon layer during an anneal at an elevated temperature in an ultrahigh vacuum environment. Alternately, a graphene layer can be deposited on an exposed surface of the single crystalline silicon carbide layer. A graphene layer can also be formed directly on a surface of a sapphire substrate or directly on a surface of a silicon carbide substrate. Still alternately, a graphene layer can be formed on a silicon carbide layer on a semiconductor substrate. The commercial availability of sapphire substrates and semiconductor substrates with a diameter of six inches or more allows formation of a graphene layer on a commercially scalable substrate for low cost manufacturing of devices employing a graphene layer.
1. A method of forming a graphene layer on a sapphire substrate, said method comprising:
forming a single crystalline semiconductor-carbon alloy layer on a sapphire substrate, wherein a (110) surface of a cubic crystal structure of said single crystalline semiconductor-carbon alloy layer is epitaxially aligned to a (1102) surface of said sapphire substrate; and
forming a graphene layer directly on another (110) surface of said single crystalline semiconductor-carbon alloy layer.
2. The method of claim 1 , wherein said graphene layer is formed by conversion of a top layer of said single crystalline semiconductor-carbon alloy layer.
3. The method of claim 2 , wherein said conversion is effected by evaporating semiconductor atoms from said top layer at an elevated temperature from 800° C. to 2,000° C.
4. The method of claim 1 , wherein said graphene layer is formed by deposition of carbon atoms that form said graphene layer on a top surface of said single crystalline semiconductor-carbon alloy layer.
5. The method of claim 4 , wherein said graphene layer is formed by decomposition of a carbon-containing precursor at said top surface of said single crystalline semiconductor-carbon alloy layer.
6. The method of claim 1 , wherein said single crystalline semiconductor-carbon alloy layer is a single crystalline silicon carbide layer having a hexagonal or cubic crystal structure.