Science and Metrology of defects in graphene using Raman Spectroscopy

This article offers a historical account of the evolution of defect metrology in graphene through Raman spectroscopy over the past five decades. The application of Raman scattering to the investigation of disorder levels in graphite materials dates back to the 1970s, and substantial advancements have occurred in this field, especially following the isolation of graphene in 2006. The article starts presenting the physics related to structural defects disrupting the translational symmetry in crystalline solids, introducing a relaxation of selection rules in Raman spectroscopy that manifests as peaks induced by disorder, then it delves into significant milestones and provides a practical summary of the principal existing protocols. Furthermore, we explore the contribution of tip-enhanced Raman spectroscopy to gaining deeper insights into fundamental aspects of defects in graphene materials, owing to its capacity for spectroscopic measurements with high spatial resolution. In conclusion, we outline prospects for the further utilization of this innovative technique in enhancing both the science and metrology of defects in graphene and its applications in other two-dimensional systems.