Fig. 5: Raman spectroscopy characterization of the bulk and few-layer SnTiS₃ flakes.

a, b Phonon modes of the SnS, TiS₂, and as-grown bulk SnTiS₃ crystal. c Raman spectra of SnTiS₃ with different layer thickness under excitation of 532 nm laser light. d A_g and A_1g Raman peak positions of SnTiS₃ with different number of layers.