Mechanochemical control of graphene etching along zigzag and armchair edge directions

The atomic edge structures of graphene mainly govern its unique electronic properties with the application in nanoscale electronics and optoelectronics. However, the development of a precision etching process with meticulous control over its edge directionality remains elusive. Here, we present a novel approach utilizing scanning probe lithography (SPL) facilitated by mechanochemical atomic attrition process, employing an active probe. This technique enables the fabrication of nanopatterns in single-layer graphene from the graphene edges, precisely along the crystallographic orientation of zigzag and armchair edges, without inducing mechanical damage to the surrounding area. Density functional theory (DFT) calculations revealed that the dissociation of C-C bonds by the SPL probe is mediated by the formation of interfacial bridge bonds between the graphene edge and the reactive silica surface. This SPL-based mechanochemical etching method will enable the construction of various nanodevice structures with specific edge orientations, which allows exploiting their electronic properties.