Raman Spectroscopy of Atomically Thin MX$_{2}$ Materials

There has been growing interest in atomically thin layers of MX$_{2}$ materials, such as MoS$_{2}$, WS$_{2}$, MoSe$_{2}$, and WSe$_{2}$. Monolayers of these materials exhibit many physical properties distinctly different from those of bulk crystals, such as a direct rather than an indirect band gap, strong photoluminescence, and large exciton binding energies. Raman spectroscopy provides a powerful tool to characterize atomically thin 2D materials, having been utilized to probe the electron-phonon coupling and identify the layer thickness of MX$_{2}$ materials. To better understand Raman spectra, we perform systematic studies of Raman scattering in different MX$_{2}$ materials as a function of the photon excitation energy, light polarization, and spatial position. I will discuss their implications for quantitative characterization of MX$_{2}$ materials using Raman spectroscopy.