We demonstrate an innovative concept for nanoscale electro-optic switching. It exploits the frequency shift of a narrow-band Fano resonance mode in a plasmonic planar metamaterial induced by a change in the dielectric properties of an adjacent chalcogenide glass layer. An electrically stimulated transition between amorphous and crystalline forms of the glass brings about a 150 nm shift in the near-infrared resonance providing transmission modulation with a contrast ratio of 4:1 in a device of subwavelength thickness.

Although new spintronic devices based on the giant spin-orbit splitting of single-layer ${\mathrm{MoS}}_2$ have been proposed, such splitting has not been studied effectively in experiments. This Letter reports the valence band spin-orbit splitting in single-layer ${\mathrm{MoS}}_2$ for the first time, probed by the triply resonant Raman scattering process. We found that upon 325 nm laser irradiation, the second order overtone and combination Raman modes of single-layer ${\mathrm{MoS}}_2$ are dramatically enhanced. Such resonant Raman enhancement arises from the electron-two-phonon triple resonance via the deformation potential and Fröhlich interaction. As a sensitive and precise probe for the spin-orbit splitting, the triply resonant Raman scattering will provide a new and independent route to study the spin characteristics of ${\mathrm{MoS}}_2$.

Nano-scale MoS₂ thin films are successfully deposited on a variety of substrates by atmospheric pressure chemical vapor deposition (APCVD) at ambient temperature, followed by a two-step annealing process. These annealed MoS₂ thin films are characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), micro-Raman, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-VIS-NIR spectrometry, photoluminescence (PL) and Hall Effect measurement. Key optical and electronic properties of APCVD grown MoS₂ thin films are determined. This APCVD process is scalable and can be easily incorporated with conventional lithography as the deposition is taking place at room temperature. We also find that the substrate material plays a significant role in the crystalline structure formation during the annealing process and single crystalline MoS₂ thin films can be achieved by using both c-plane ZnO and c-plane sapphire substrates. These APCVD grown nano-scale MoS₂ thin films show great promise for nanoelectronic and optoelectronic applications.