Exciton–Phonon Interactions in Strained Domes of Monolayer MoS(2) Studied by Resonance Raman Spectroscopy

This work describes a resonance Raman study performed in the domes of monolayer MoS(2) using 23 different laser excitation energies covering the visible and near-infrared (NIR) ranges. The multiple excitation results allowed us to investigate the exciton–phonon interactions of different phonons (A [Formula: see text] (1), E [Formula: see text] , and LA) with different excitonic optical transitions in biaxially strained monolayer MoS [Formula: see text]. The analysis of the intensities of the two first-order peaks, A [Formula: see text] (1) and E [Formula: see text] , and the double-resonance 2LA Raman band as a function of the laser excitation furnished the values of the energies of the indirect exciton and the direct excitonic transitions in the strained MoS [Formula: see text] domes. It was noticed that the out-of-plane A [Formula: see text] (1) phonon mode is significantly enhanced only by the indirect exciton I and the C exciton, whereas the in-plane E [Formula: see text] mode is only enhanced by the C exciton of the MoS(2) dome, thus revealing the weak interaction of these phonons with the A and B excitons in the strained MoS [Formula: see text] domes. On the other hand, the 2LA Raman band is significantly enhanced at the indirect exciton I and by the A (or B) exciton but not enhanced by the C exciton, thus showing that the LA edge phonons that participate in the double-resonance process in MoS [Formula: see text] have a weak interaction with the C exciton.