Showing papers by "Satoshi Kawata published in 2018"
TL;DR: Raman scattering measurements of monolayer WS2 are reported as a function of the laser excitation energies from the near-infrared to the deep-ultraviolet and several strong Raman peaks in the range of 700∼850 cm−1 with theDeep-ult ultraviolet laser lights are observed.
Abstract: Raman scattering measurements of monolayer WS2 are reported as a function of the laser excitation energies from the near-infrared (158 eV) to the deep-ultraviolet (482 eV) In particular, we observed several strong Raman peaks in the range of 700∼850 cm−1 with the deep-ultraviolet laser lights (466 eV and 482 eV) Using the first-principles calculations, these peaks and other weak peaks were appropriately assigned by the double resonance Raman scattering spectra of phonons around the M and K points in the hexagonal Brillouin zone The relative intensity of the first-order $${{\boldsymbol{E}}}_{{\bf{2}}{\boldsymbol{g}}}^{{\bf{1}}}$$
to A1g peak changes dramatically with the 158 eV and 233 eV laser excitations, while the comparable relative intensity was observed for other laser energies The disappearance of the $${{\boldsymbol{E}}}_{{\bf{2}}{\boldsymbol{g}}}^{{\bf{1}}}$$
peak with the 158 eV laser light comes from the fact that valley polarization of the laser light surpasses the $${{\boldsymbol{E}}}_{{\bf{2}}{\boldsymbol{g}}}^{{\bf{1}}}$$
mode since the $${{\boldsymbol{E}}}_{{\bf{2}}{\boldsymbol{g}}}^{{\bf{1}}}$$
mode is the helicity-exchange Raman mode On the other hand, the disappearance of the A1g peak with the 233 eV laser light might be due to the strain effect on the electron-phonon matrix element
15 citations
TL;DR: In this article, the use of supercritical carbon dioxide fluid for the non-destructive extraction of nanostructures was discussed and the laser power dependence of resultant structures was discussed.
Abstract: In a previous report, a self-growing approach was proposed for fabricating complex silver nanostructures, where silver dendrites were grown at silver nanoseeds in silver ion solution owing to plasmonic heating with ultraviolet light. Structures were deformed or destroyed when they were extracted with acetone and dried in air. In this Letter, we discuss the use of supercritical carbon dioxide fluid for the nondestructive extraction of nanostructures. We show the experimental results and discuss the laser power dependence of resultant structures. Another experiment was performed for nanostructure growth inside an agarose gel as a matrix. Silver nanostructures were immobilized without damage in an agarose skeleton network.
5 citations