We report non-resonant and resonant Raman scattering studies of layered MoS2. Owing to its reduced dimensionality, few layered MoS2 is more sensitive to the difference between inter- and intra-layer coupling, which results in unusual frequency shifts of the Raman phonon modes. In addition, relative intensities between the two Raman active phonon modes E2g1 and A1g unexpectedly depend on the laser excitation energy, which might be associated with the electronic band structure, including spin-orbit coupling and phonon dispersions. Through resonant Raman scattering measurements, the indirect-to-direct band gap behavior and electron-phonon interaction information were obtained. Raman scattering spectroscopy is seen to be very effective for studying the layer-dependent characteristics of layered MoS2.
- Raman scattering