Anisotropic electron–photon–phonon coupling in layered MoS<sub>2</sub>
Deepu Kumar, Birender Singh, Rahul Kumar, Mahesh Kumar, Pradeep Kumar
Abstract
Transition metal dichalcogenide, MoS 2 has attracted a lot of attention recently owing to its tunable visible range band gap, and anisotropic electronic and transport properties. Here, we report comprehensive inelastic light scattering measurements on both chemical vapor deposition grown (horizontally and vertically aligned) flakes, and mechanically exfoliated flakes of single crystal MoS 2 . We probe the anisotropic optical response by studying the polarization dependence intensity of the Raman active phonon modes as a function of different incident photon energy and flake thickness. Our polarization dependent Raman studies reveal strong anisotropic behavior reflected in the anomalous renormalization of the modes intensity as a function of flake thickness, phonons and photon energy. Our observations reflect the strong anisotropic light–matter interaction in this high crystalline symmetric layered MoS 2 system, especially for the in-plane vibrations, crucial for understanding as well as future applications of these materials.