sSNOM characterization of the IR-active vibrational mode in highly strained hBN

Hexagonal Boron Nitride is a layered insulator often employed as a protective layer for heterostructures or as host for single photon emitters. In particular, the emission of defects in hBN can be tuned by strain, and it is therefore of the utmost importance to have a reliable method to quantify strain in this system. Here we present a sSNOM experiment on micrometric-sized bubbles of hBN with the aim of addressing the response to strain of the transverse optical IR-active mode.