Measurement of local optomechanical properties of MoSe2 monolayers

Strain engineering is a powerful tool for tuning physical properties of 2D materials, including thin layers of transition metal dichalcogenides (TMDs). Here we study experimentally the achievable local excitonic spectral shifts through a combination of a controllable deformation experiment with in-situ optical characterization, rigorous numerical simulations, and careful account for the optical resolution of the setup. We extract the spatial profiles of strain-induced exciton energy shift depending on the depth of the local indentation of a 2D semiconductor performed by an AFM tip and unambiguously detect the flake rupture. This allows us to systematically investigate the optomechanical properties of TMD monolayers at each indentation depth. Our approach is a powerful tool for in-situ characterization of local optomechanical properties of two-dimensional semiconductors with a strong excitonic response.