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Structure and vibrational spectra of ReSe 2 nanoplates
Author(s) -
Yukhymchuk Volodymyr O.,
Kulikov Leonid M.,
Valakh Mykhailo Y.,
Litvinchuk Alexander P.,
Skoryk Mykola A.,
Mazur Nazar V.,
Yefanov Volodymyr S.,
Selyshchev Oleksandr,
Dzhagan Volodymyr M.,
Zahn Dietrich R.T.
Publication year - 2020
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5898
Subject(s) - raman spectroscopy , phonon , brillouin zone , triclinic crystal system , chemistry , infrared , molecular vibration , molecular physics , condensed matter physics , pseudopotential , materials science , crystallography , optics , physics , crystal structure
Theoretical and experimental vibrational spectra of ReSe 2 nanocrystals, synthesized by self‐limited chemical vapor deposition (CVD), are reported. Scanning electron microscopy reveals that the nanocrystals have the shape of polygon nanoplates (NPs), 20 nm thick and about 100–300 nm wide. X‐ray diffraction studies determined their triclinic structure (space group, P‐1 [no. 2]). The wavenumbers of the Raman‐ and infrared (IR)‐active phonon modes were calculated using the density functional perturbation theory (DFPT), along with the dispersion curves and phonon density of states. The set of theoretical phonon wavenumbers is found to correlate well with the experimental Raman and IR spectra. We established that, unlike ReS 2 , ReSe 2 does not exhibit a “phonon gap.” Several “extra” bands in the experimental Raman spectrum of ReSe 2 are argued to be defect‐induced contributions of phonons from F and Q critical points of the Brillouin zone. In addition, the effect of Fermi resonance is observed in the Raman spectrum of the ReSe 2 NPs, which manifests itself in an increase of the intensity of second‐order bands due to their interaction with first‐order phonons.