Raman scattering of true 1D van der Waals Nb₂Se₉ nanowires

In the present study, the experimental Raman spectrum of niobium-selenide nanowires (Nb₂Se₉) is reported for the first time followed by an analysis of the Raman spectrum using the density functional theory (DFT). According to the group-theoretical analysis, 33 A_g modes were identified as Raman active modes. In the experimental spectrum, 19 well-resolved Raman modes were observed: 13 modes in the low-wavenumber range (50–200 cm⁻¹) and six modes in the high-wavenumber range (220–340 cm⁻¹). The DFT calculations were performed using the local-density approximation (LDA) functional and generalized gradient approximation (GGA) functional of Perdew–Burke–Ernzerhof (PBE) with van der Waals corrections (PBE-D3). PBE-D3 showed better compatibility with the experimental data for the high-wavenumber range. Our results provide an essential reference for the Raman scattering of newly synthesized Nb₂Se₉ nanowires and nanodevices in the future.