Insights into vibrational and electronic properties of MoS using Raman, photoluminescence and transport studies
arXiv:1502.03452
Abstract
We review vibrational and electronic properties of single and a few layer MoS relevant to understand their resonant and non-resonant Raman scattering results. In particular, the optical modes and low frequency shear and layer breathing modes show significant dependence on the number of MoS layers. Further, the electron doping of the MoS single layer achieved using top-gating in a field effect transistor renormalizes the two optical modes A and E differently due to symmetry-dependent electron-phonon coupling. The issues related to carrier mobility, the Schottky barrier at the MoS-metal contact pads and the modifications of the dielectric environment are addressed. The direct optical transitions for single layer-MoS involve two excitons at K-point in the Brillouin zone and their stability with temperature and pressure has been reviewed. Finally, the Fermi-level dependence of spectral shift for a quasiparticle, called trion, has been discussed.
76 pages, 49 figures
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