An in-depth study of the synthesis of ReSe₂ for anisotropic Raman characteristics

Two-dimensional transition metal dichalcogenides (TMDs) have received more interest for their potential role in future electronic and optoelectronic applications. Unlike other TMDs, Rhenium diselenide (ReSe₂) stands out for its distinctive anisotropic growth characteristics. These unique features arise from its low lattice symmetry and interlayer decoupling, this has sparked significant interest among researchers. Previous research has indicated the presence of various growth patterns, including dendritic formations and structures resembling flowers. In this study, we effectively produced ReSe₂ using the ‘Tilting Boat’ method to achieve growth on a 21 μm scale. Through precise manipulation of the growth conditions, we successfully attained flakes of 21 μm scale in comparison to prior findings. Moreover, we successfully produced a variety of shapes, including triangles, diamonds, and hexagons, on 1 × 1 cm² Si/SiO₂ substrates. Furthermore, we achieved the successful production of a continuous ReSe₂ film on a 1 × 3 cm² Al₂O₃ substrate. We verified the distinct anisotropic properties of ReSe₂ via Raman Spectroscopy. Furthermore, we acquired three-dimensional visual representations of ReSe₂ flakes and continuous films via SEM measurements. By employing EDS data and analysing x-ray photoelectron spectroscopy spectra, we have established a compositional ratio of 1:2 for Re and Se, which aligns with the MX₂ structure. This confirmation indicates the successful synthesis of high-quality ReSe₂ flakes.