Revealing the Optical Anisotropy of ReS2 Nanostructures by Strain Engineering

Two-dimensional (2D) anisotropic materials possess asymmetric atomic arrangements and normally exhibit physicochemical properties distinguishably along different crystal orientations, offering a brand-new degree of freedom for fabricating conceptual devices. Developing a feasible strain loading method for materials with nonorthogonal crystalline axes is necessary, enabling a deeper understanding of the 2D anisotropy of such materials, which is of valuable guidance for the optimization of optoelectronic devices. Here, we proposed a uniaxial strain loading method by rotation and examined the trend of optical properties of anisotropic ReS2 under strain applied along the a- and b-axis strain directions. From the Raman and photoluminescence spectra, it can be seen that the vibrational and optical responses achieve the maximum under the strain that is applied uniaxially along the crystalline b-axis. Our work provides a reliable strategy to tailor the anisotropic optical properties, making it feasible to selectively improve the material performance of ReS2 nanostructures-based optoelectronic and logic devices in the future.