Spatially resolved electron energy-loss spectroscopy of MoS₂ platelets

Surface and edge excitations in submicron hexagonal MoS₂ platelets are examined with inelastic electron scattering. An ultra-high vacuum STEM equipped with both vacuum transfer and in situ sample treatment facilities provides the capacity to study the surface properties of important air-sensitive materials. Energy-filtered images obtained with various geometries of the incident beam with respect to the sample suggest the enhancement of surface plasmon modes at corners, edges and steps. Initial efforts to interpret grazing incidence spectra from materials with highly anisotropic dielectric functions are reported.