CVD Growth of Rhenium diselenide (ReSe₂) on Silica Substrate

Flakes of ReSe₂ were grown by a chemical vapor deposition technique on silica substrates and investigated at room temperature by using Raman and absorption spectroscopies. The Raman scattering spectrum exhibits sixteen phonon modes in the range of 100 - 300 cm^-1 while the calculated modes were eighteen as obtained by the density functional theory (DFT) calculations. The ReSe₂ structural integrity was confirmed by using the XRD and scanning electron microscopy while energy dispersion spectroscopy confirms the correct elemental composition. The absorption peaks were obtained for ReSe2 flakes and found to be in the spectral region of 885 - 942 nm (1.401 – 1.316 eV) indicating a direct band gap. This is confirmed by the DFT calculations that revealed a direct bandgap of 1.19 eV for ReSe₂.