Low-Frequency Raman Spectroscopy of Few-Layer 2H-SnS2.

ABSTRACT: We investigated interlayer phonon modes of mechanically exfoliated few-layer 2H-SnS2 samples by using room temperature low-frequency micro-Raman spectroscopy. Raman measurements were performed using laser wavelengths of 441.6, 514.4, 532 and 632.8?nm with power below 100??W and inside a vacuum chamber to avoid photo-oxidation. The intralayer Eg and A1g modes are observed at ~206?cm-1 and 314?cm-1, respectively, but the Eg mode is much weaker for all excitation energies. The A1g mode exhibits strong resonant enhancement for the 532?nm (2.33?eV) laser. In the low-frequency region, interlayer vibrational modes of shear and breathing modes are observed. These modes show characteristic dependence on the number of layers. The strengths of the interlayer interactions are estimated by fitting the interlayer mode frequencies using the linear chain model and are found to be 1.64?×?1019?N?·?m-3 and 5.03?×?1019?N?·?m-3 for the shear and breathing modes, respectively.

SUBMITTER: Sriv T 

PROVIDER: S-EPMC6033902 | biostudies-other | 2018 Jul

REPOSITORIES: biostudies-other