PROCESS FOR PRODUCING CATALYST METAL LAYER AND PROCESS FOR PRODUCING GRAPHENE MATERIAL
First, a quadrilateral substrate (12) comprising c-plane sapphire is prepared, and nickel is deposited as a catalyst metal on the entire upper surface of the substrate (12) to form a catalyst metal film (14) (see (a)). Next, the catalyst metal film (14) is patterned by lithography to form a catalyst metal film (16) having a given shape (see (b)). Subsequently, the temperature of the catalyst metal film (16) is elevated to 1,000 C and kept at 1,000 C for 20 minutes. The temperature of the catalyst metal film (16) is then lowered from 1,000 C to 800 C at a rate of 5 C/min and is kept at 800 C for 15 hours. Thus, a catalyst metal layer (17) constituted of large grains is obtained (see (c)). Thereafter, a carbon source is supplied to the surface of the catalyst metal layer (17) to grow graphene, and the catalyst metal layer (17) is dissolved away with an acidic solution to take out a graphene material (10) (see (d) to (g)).