▎ 摘　　要

We present a study on oxidation scanning probe lithography (o-SPL) of chemical vapor deposition grown graphene conducted under a pulsed voltage bias (V-bias) with millisecond rise time. It is found that the o-SPL patterns are circular ring-like trenches. The size of the ring-like trenches increase as the V-bias and relative humidity increase. Combining detailed analysis and numerical calculation, it is concluded that the balance between water condensation energy and electrostatic energy is the deterministic factor that define the shape and boundary of the water meniscus, within which the o-SPL process takes place. The oxidation process starts over a common threshold V-bias and stops at the outer edge of the water meniscus, which broadens under more negative V-bias and higher relative humidity. The two-dimensional nature of graphene leads to insulation of the encircled central disk from the rest of the graphene sheet after the oxidation of the trenches and results in a small graphene disk with size about 50 nm under all o-SPL conditions.