Preparation and polarized Raman scattering Characterization of a Vanadium based Misfit Chalcogenide

Abstract

Compounds [(MX)1+δ]m[(TX2)n] are two-dimensional misfit layer dichalcogenides characterized by alternating layers of MX (Rock Salt structure) and TX2 (Transition metal dichalcogenide) where M can be elements such as Sn, Pb, Bi or rare earth metals; X can be S or Se; and T can be Ti, V, Nb, Ta or Cr. This study focuses on synthesizing single crystals of [(SnSe)1+δ]m[(V Se2)n] using chemical vapor transport with anhydrous NH4Cl as the transport agent. Among the various by-products, mixed crystals containing thin layers of [(SnSe)1+δ]m[(V Se2)n] were successfully created, displaying monolayer, bilayer, and trilayer misfit compounds. Topographical and elemental analysis using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray spectroscopy (EDS) confirmed the stoichiometry of the synthesized compounds from which their layering arrangement was deduced. Further, the polarization-dependent vibrational modes of the parent compound (V Se2) and monolayered [(SnSe)1+δ]m[(V Se2)n] (m, n = 1) were investigated through optical Raman spectroscopy measurements.