▎ 摘　　要

NOVELTY - Preparing high-purity semi-insulating silicon carbide substrate-based periodic pn junction graphene, comprises e.g. (i) cutting, grinding and polishing high-purity semi-insulating 4H-silicon carbide crystals, (ii) placing crucible containing silicon carbide wafer substrate prepared in step (i) in chamber of intermediate frequency induction heating furnace for vacuum high-temperature impurity removal, (iii) pouring hydrogen into furnace cavity to perform hydrogen etching on silicon surface of silicon carbide wafer substrate, and forming regular silicon carbide step structure on surface, (iv) stopping passing hydrogen and argon gas, heating, growing structure of graphene strips and buffer layer strips high-purity semi-insulating silicon carbide substrate surface, and cooling, and (v) pouring mixture of hydrogen and argon into furnace cavity, passivating on structure sample substrate with graphene and buffer layer periodically arranged in step (iv). USE - The high-purity semi-insulating silicon carbide substrate-based periodic pn junction graphene is useful in the field of information electronic devices, in enhanced photodetectors, photosensitive elements and logic operation field effect transistors (all claimed). ADVANTAGE - The pn junction graphene has high-quality. DETAILED DESCRIPTION - Preparing high-purity semi-insulating silicon carbide substrate-based periodic pn junction graphene, comprises (i) cutting, grinding and polishing high-purity semi-insulating 4H-silicon carbide crystals to obtain high-purity semi-insulating silicon carbide wafer substrate, which can use after cleaning, (ii) placing the crucible containing silicon carbide wafer substrate prepared in step (i) in the chamber of intermediate frequency induction heating furnace for vacuum high-temperature impurity removal, (iii) pouring hydrogen into furnace cavity to perform hydrogen etching on silicon surface of silicon carbide wafer substrate to obtain high-purity semi-insulating silicon carbide substrate after hydrogen etching, and forming regular silicon carbide step structure on the surface, (iv) stopping passing hydrogen, and argon gas, then heating, growing the structure of graphene strips and buffer layer strips on the surface of high-purity semi-insulating silicon carbide substrate after hydrogen etching prepared in step (iii), and cooling to room temperature to obtain structure sample substrate in which graphene and buffer layers are periodically arranged, and (v) pouring mixture of hydrogen and argon into furnace cavity to increase the temperature, performing passivation treatment on the structure sample substrate with graphene and buffer layer periodically arranged in step (iv) to obtain final product. An INDEPENDENT CLAIM is also included for high-purity semi-insulating silicon carbide substrate-based periodic pn junction graphene prepared by above method.