Tip‐Enhanced Raman Spectroscopy Coherence Length of 2D Materials: An Application to Graphene

Abstract

Herein, a protocol is presented for determining the tip‐enhanced Raman spectroscopy (TERS) coherence length (Lc) of the two main Raman bands of graphene. This method involves performing approach curve experiments and plotting the normalized areas of the G and 2D bands as a function of tip–sample distance. The resultant data are fitted using a specific TERS formula to extract Lc. The results indicate different coherence lengths for the G and 2D bands in graphene as and nm. While this protocol is specifically done for graphene, the underlying theoretical framework, based on mode symmetry, can be extended to other 2D materials, such as transition metal dichalcogenides. This demonstrates the versatility and potential of TERS in exploring the coherence properties of various 2D materials.