Studying 2D Materials with Advanced Raman Spectroscopy: CARS, SRS and TERS

Raman spectroscopy is established as a valuable tool to study and characterize two-dimensional (2D) systems, but it exhibits two drawbacks: a relatively weak signal response and a limited spatial resolution. Recently, advanced Raman spectroscopy techniques, such as coherent anti-Stokes spectroscopy (CARS), stimulated Raman scattering (SRS) and tip-enhanced Raman spectroscopy (TERS) have been shown to overcome these two limitations. In this article we review how useful physical information can be retrieved from different 2D material with these three advanced Raman spectroscopy and imaging techniques, discussing results on graphene, hexagonal boron-nitride, transition metal di- and mono-chalcogenides, thus providing perspectives for future work in this early-stage field of research, including similar studies on unexplored 2D systems and open questions.