Temperature-dependent Raman spectroscopy studies of the interface coupling effect of monolayer ReSe2 single crystals on Au foils

Rhenium diselenide (ReSe₂), which bears in-plane anisotropic optical and electrical properties, is of considerable interest for its excellent applications in novel devices, such as polarization-sensitive photodetectors and integrated polarization-controllers. However, great challenges to date in the controllable synthesis of high-quality ReSe₂ have hindered its in-depth investigations and practical applications. Herein, we report a feasible synthesis of monolayer single-crystal ReSe₂ flakes on the Au foil substrate by using a chemical vapor deposition route. Particularly, we focus on the temperature-dependent Raman spectroscopy investigations of monolayer ReSe₂ grown on Au foils, which present concurrent red shifts of E_g-like and A_g-like modes with increasing measurement temperature from 77-290 K. Linear temperature dependences of both modes are revealed and explained from the anharmonic vibration of the ReSe₂ lattice. More importantly, the strong interaction of ReSe₂ with Au, with respect to that with SiO₂/Si, is further confirmed by temperature-dependent Raman characterization. This work is thus proposed to shed light on the optical and thermal properties of such anisotropic two-dimensional three-atom-thick materials.