Observation of forbidden phonons and dark excitons by resonance Raman scattering in few-layer WS${}_2$

Qing-Hai Tan, Yu-Jia Sun, Xue-Lu Liu +4

The optical properties of the two-dimensional (2D) crystals are dominated by tightly bound electron-hole pairs (excitons) and lattice vibration modes (phonons). The exciton-phonon…