▎ 摘　　要

Current annealing behaviors that directly contribute to excellent electrical transport properties in suspended graphene devices are investigated. All successful annealing data for various thicknesses of graphene exhibit three different stages in current-voltage curves upon bias voltage application: (1) sublinear increase in current, (2) abrupt current decrease, and (3) current saturation. This can be attributed to the phonon effect and the structural deformation of graphene at high temperatures induced by Joule heating. It is observed that cleaning occurred primarily in the last stage when the current becomes saturated.