▎ 摘　　要

NOVELTY - Preparation of N-type graphene field effect transistor involves mixing crystalline graphene, sodium nitrate and concentrated sulfuric acid, adding potassium permanganate, stirring, heating, adding deionized water, and stirring in deionized water and hydrogen peroxide; adding dilute nitric acid and depositing; adding deionized water and depositing; condensing and drying; adding ethanol, ultrasonic treating, and spin coating in substrate; placing in quartz boat and carrying out light reduction; removing thin film; and depositing in gold electrode and draining electrode. USE - Method for preparing N-type graphene field effect transistor (claimed). ADVANTAGE - The method is convenient and suitable for large scale preparation and has low cost. DETAILED DESCRIPTION - Preparation of N-type graphene field effect transistor comprises: (A) mixing 6-10 g crystalline flake graphene, 6-10 g sodium nitrate and 350-400 mL concentrated sulfuric acid in ice bath, slowly adding 45-55 g potassium permanganate, magnetically stirring for 2 hours, heating at 35 degrees C, adding 320 mL deionized water, stirring for 15 minutes, adding 800 mL deionized water and 40 mL hydrogen peroxide, and stirring for 10 minutes; (B) adding 0.0001 mol/L dilute nitric acid and depositing at 14000 revolutions/minute (rpm); repeating second step for 2-3 times; (C) adding deionized water and high speed depositing at 14000 rpm; (D) repeating fourth step by adding deionized water and centrifuging for 10 times; (E) condensing and drying; (F) adding 80-90% ethanol to obtain 1 mg/mL concentration, ultrasonic treating for 25-35 minutes, and spin coating on 0.3-0.8 mm silica/silicon substrate at thickness of 200-500 nm to obtain graphene oxide (GO) film, where atomic ratio of oxygen to carbon in GO is 2:5 and thickness of GO film is 30-100 nm; (G) placing in quartz boat, placing in light reduction device, placing above light source, where frequency spectrum range of light source is 200-760 nm and light source is monochromatic light or white light, and carrying out light reduction of GO thin film at 10-30 torr under ammonia gas atmosphere and laser or mercury lamp at 65-75 mJ/cm2 to obtain nitrogen-doped graphene thin film, where illumination time is 5-60 minutes; (H) removing thin film; and (I) depositing in gold electrode and draining electrode.