Tip-enhanced Raman mapping of local strain in graphene

This is the authors' abstract. We don't add key points for this paper.

We demonstrate local strain measurements in graphene by using tip-enhanced Raman spectroscopy (TERS). We find that a single 5 nm particle can induce a radial strain over a lateral distance of ∼170 nm. By treating the particle as a point force on a circular membrane, we find that the strain in the radial direction (r) is ∝ r−(2 3),in agreement with force-displacement measurements conducted on suspended graphene flakes. Our results demonstrate that TERS can be used to map out static strain fields at the nanoscale, which are inaccessible using force-displacement techniques.