▎ 摘　　要

NOVELTY - Preparing a crystalline graphene (12, 14), comprises: performing a first thermal treatment including supplying heat to an inorganic substrate (11) in a reactor; introducing a vapor carbon supply source into the reactor during the first thermal treatment to form activated carbon; and binding the activated carbon on the inorganic substrate to grow the crystalline graphene. USE - The method is useful for preparing crystalline graphene, which is useful: in electronic device (all claimed); as a transparent electrode; in a solar cell; as a panel conducting thin layer of a display device; and as a channel for memory devices, sensors or electronic paper. ADVANTAGE - The method: provides the crystalline graphene, which exhibits high conductivity and uniformity of the graphene layer, and improved crystallinity; is capable of directly growing graphene on a target substrate without needing a separate transfer process, hence it is simple; and suppresses the damage of graphene. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) the crystalline graphene obtained by the method, where the crystalline graphene has a D-band to G-band peak intensity ratio of less than or equal to 0.5; (2) a graphene-on-substrate, comprising: the inorganic substrate; and the crystalline graphene disposed on at least one surface of the inorganic substrate, where the crystalline graphene is directly grown on the inorganic substrate by a growing process; and (3) an electronic device comprising the graphene-on-substrate. DESCRIPTION OF DRAWING(S) - The figure illustrates a schematic diagram of a method of directly growing graphene. Inorganic substrate (11) Crystalline graphene (12, 14) Graphitization catalyst layer (13)