Raman Characterization of the Charge Density Wave Phase of 1T-TiSe2: From Bulk to Atomically Thin Layers

摘要: Raman scattering is a powerful tool for investigating the vibrational properties of two-dimensional materials. Unlike 2H phase many transition metal dichalcogenides, 1T TiSe2 features Raman-active shearing and breathing mode, both which shift toward lower energy with increasing number layers. By systematically studying signal 1T-TiSe2 in dependence sheet thickness, we demonstrate that charge density wave this compound can be reliably determined from temperature peak position Eg mode near 136 cm–1. The found to first increase decreasing thickness sheets, followed by decrease due effect surface oxidation. spectroscopy-based method expected applicable also other 1T-phase dichalcogenides featuring represents valuable complement electrical transport-based approaches.