▎ 摘　　要

NOVELTY - Producing a graphene film comprises: (a) providing a substrate (5) having a catalyst layer (15) in contact with an electrically insulating self-support (20), where the catalyst layer comprises a catalytic monocrystalline zone (45) containing more than 99.9 wt.% platinum or more than 99.9 wt.% platinum alloy having more than 50 (preferably more than 80) wt.% platinum; and (b) forming a graphene film by epitaxial deposition in contact with the catalytic monocrystalline zone of the substrate by using a chemical vapor deposition device. The electrically insulating support extends along a longitudinal surface and has an electrically insulating monocrystalline zone (25) containing more than 99.9 wt.% oxide e.g. magnesium oxide. The catalytic monocrystalline zone is epitaxially grown on the electrically insulating monocrystalline zone. USE - The process is useful for producing a graphene film (claimed) which is useful in the field of nanoelectronics, photovoltaic cells and biological sensors. ADVANTAGE - The process: produces high quality graphene film having low roughness and high crystalline quality in industrial quantities with a low content of impurities; and favors epitaxial growth of the catalytic monocrystalline zone on the electrically insulating monocrystalline zone, while reducing the density of crystalline defects in the catalytic monocrystalline zone, thus limiting the number of grains in the graphene film and resulting in electrical properties suitable for nanoelectronics applications and biological sensors. DETAILED DESCRIPTION - Producing a graphene film comprises: (a) providing a substrate (5) having a catalyst layer (15) in contact with an electrically insulating self-support (20), where the catalyst layer comprises a catalytic monocrystalline zone (45) containing more than 99.9 wt.% platinum or more than 99.9 wt.% platinum alloy having more than 50 (preferably more than) 80 wt.% platinum; and (b) forming a graphene film by epitaxial deposition in contact with the catalytic monocrystalline zone of the substrate by using a chemical vapor deposition device. The electrically insulating support extends along a longitudinal surface and has an electrically insulating monocrystalline zone (25) containing more than 99.9 wt.% oxide comprising magnesium oxide, germanium dioxide, alpha -alumina, praseodymium(III) oxide, alpha - iron(III) oxide, titanium dioxide, barium titanate, cerium(IV) oxide, zirconium dioxide, hafnium(IV) oxide, tantalum pentoxide, strontium oxide, barium zirconate, strontium zirconate, lanthanum aluminate, yttrium aluminate, praseodymium selenium oxide (PrSeO3) (sic), calcium oxide, selenium oxide (Se2O3), barium oxide, lutetium(III) oxide, lanthanum oxide, lanthanum scandium oxide, gadolinium scandium oxide (GdSc2O3), scandium(III) oxide, yttrium trioxide, yttrium aluminum garnet and/or magnesium aluminum oxide. The catalytic monocrystalline zone is epitaxially grown on the electrically insulating monocrystalline zone. The electrically insulating monocrystalline zone has a thickness (e1), measured in a direction normal to the longitudinal surface, of greater than 0.1 mm. The face of the catalytic monocrystalline zone opposite to the face of the catalytic monocrystalline zone in contact with the support has a roughness of less than 5 nm. DESCRIPTION OF DRAWING(S) - The figure shows a substrate for producing a graphene film. Substrate (5) Catalyst layer (15) Electrically insulating self-support (20) Electrically insulating monocrystalline zone (25) Catalytic monocrystalline zone (45)