▎ 摘　　要

NOVELTY - Preparing graphene nanobelt comprises (1) polishing and cleaning a silicon carbide substrate to obtain a uniform flat and step-shaped silicon carbide substrate, (2) carrying out hydrogen etching of the uniform flat and step-shaped silicon carbide substrate to remove corrosion and obtain step-shaped silicon carbide substrate with surface roughness less than 0.2 nm, (3) heating the etched step-shaped silicon carbide substrate to grow graphene on the substrate, and (4) carrying out helium ion etching of the step-shaped silicon carbide substrate using a focused ion beam system. USE - The method is useful for preparing graphene nanobelt (claimed). ADVANTAGE - The method is capable of accurately and uniformly preparing the graphene nanobelt with high sensitivity and good contrast. DETAILED DESCRIPTION - Preparing graphene nanobelt comprises (1) polishing and cleaning a silicon carbide substrate to obtain a uniform flat and step-shaped silicon carbide substrate, (2) carrying out hydrogen etching of the uniform flat and step-shaped silicon carbide substrate to remove corrosion and obtain step-shaped silicon carbide substrate with surface roughness of less than 0.2 nm, (3) heating the etched step-shaped silicon carbide substrate to grow graphene on the substrate, and (4) carrying out helium ion etching of the step-shaped silicon carbide substrate for growing graphene for 1-100 mu s, using a focused ion beam system having 20 keV of ion energy level, 1-10 pA of ion beam electric current and vacuum pressure of 10-6 Torr to obtain graphene nanobelt with line width of less than 10 nm.