▎ 摘　　要

Controlling the layers and in-plane defects in multi-layer graphene is the key to exploiting the extraordinary properties of graphene. Layer-by-layer thinning under high-density oxygen neutrals was observed in situ during room-temperature reaction science using a remote oxygen plasma inside a high-voltage transmission electron microscopy. Even though the etching rate of graphene was higher at the edge than at the basal plane, etching started from both locations. Each etched layer was represented by the plasmon loss intensity in the electron energy loss spectrum. After exposure to the remote oxygen plasma, the electron diffraction pattern for the multi-layer graphene keep clear six-fold diffraction pattern. Raman spectroscopy revealed the formation of defects in multi-layer graphene. The nonthermal reaction of oxygen neutrals required for graphene etching was demonstrated by in situ transmission electron microscopy. (C) 2020 Elsevier Ltd. All rights reserved.