▎ 摘　　要

NOVELTY - Large-area boron nitride graphene vertical heterojunction film, comprises a substrate and a heterostructure layer covering the substrate. The heterostructure layer comprises boron nitride and graphene, and the boron nitride film is uniformly grown on the graphene thin layer and form an atomically thick boron nitride graphene vertical heterostructure. The heterostructure layer is a periodic stack of multiple boron nitride graphene heterostructures in a direction perpendicular to the substrate. The substrate is a dielectric substrate, which includes quartz, silicon, silicon oxide or sapphire. The graphene layer is graphene oxide, reduced graphene oxide, nanocrystalline graphene, single-layer or multi-layer graphene. USE - Large-area boron nitride graphene vertical heterojunction film for preparing the material with graphene material (claimed). ADVANTAGE - The thicknesses of boron nitride and graphene is independently regulated, and periodically expanded in the direction perpendicular to the substrate. The preparation process is simple, does not need any metal catalyst, and is eco-friendly, and also provides a very convenient process approach for the application of two-dimensional materials, such as graphene and boron nitride in van der Waals heterojunction devices. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing a large-area boron nitride graphene vertical heterojunction film, which involves: adding graphene to deionized water, forming a graphene dispersion after magnetic stirring and ultrasound, then centrifuging the graphene dispersion multiple times, collecting the supernatant after centrifugation, to obtain a stable graphene aqueous solution; adding n-pentane and acetone in turn to the obtained graphene aqueous solution, heating the mixed solution for a period of time and then standing at room temperature to obtain a large-area graphene interfacial self-assembled layer floating on the liquid surface; quickly immersing the substrate in the floating liquid of the graphene interfacial self-assembled layer to remove it, heating and drying to obtain the interfacial self-assembled graphene layer on the surface of the substrate, putting a certain amount of boron oxide powder as a precursor and a substrate with a pre-set graphene layer into a high-temperature tube furnace for heating; keeping the argon gas flowing steadily, and then passing the ammonia gas after reaching the reaction temperature for a period of time, and cooling naturally to room temperature, and growing large-area boron nitride film on the graphene layer to obtain a large-area boron nitride graphene vertical heterojunction film.