Fig. 1: Raman scattering excitation.
From: Raman scattering excitation in monolayers of semiconducting transition metal dichalcogenides
False-colour maps of optical response of the a MoS2, b MoSe2, c WS2, and d WSe2 MLs encapsulated in hBN measured at low temperature (T = 5 K) under excitation of tuneable lasers (excitation power ~ 150 μW). The maps are vertically aligned with respect to the energy distance from the energy of the neutral exciton (X) emission in these materials, which is marked on the red right-hand energy scales. The colour scales have been normalised to the maximum intensity. The detection energies of the maps are centred around the X emission. The phonon modes are visible as several narrow parallel resonances passing diagonally across the maps. For the MoS2 ML, white arrows point out lines which are investigated in the following.
