Emission Excitation Spectroscopy in WS2 Monolayer Encapsulated in Hexagonal BN

M. Zinkiewicza, K. Nogajewskia, M. Bartosb, K. Watanabec, T. Taniguchic, M. Potemskia, b, A. Babińskia, M.R. Molasa aInstitute of Experimental Physics, Faculty of Physics, University of Warsaw, L. Pasteura 5, PL-02093 Warszawa, Poland bLaboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, av. des Martyrs, 38042 Grenoble, France cNational Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan

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Resonant conditions of the Raman scattering in monolayer WS2 encapsulated in hexagonal BN are investigated using the Raman scattering excitation technique at low temperature (T=5 K). The resonance of the detected signal with the neutral exciton leads to an extremely rich Raman scattering excitation spectrum, which displays also the Raman scattering features not reported so far. Moreover, the intensities of the observed phonon modes are strongly enhanced when the energy difference between the excitation laser and the neutral exciton emission (X0) is equal to the corresponding phonon energy. The intensity profile of the out-of-plane A'1 phonon mode reflects the Lorentzian lineshape of the X0 line with the linewidth of about 4 meV, which underlines the outgoing resonance conditions with the X0 complex.

DOI:10.12693/APhysPolA.136.624 topics: tungsten disulphide monolayer, Raman scattering excitation