Polarization Raman spectra of graphene driven by monolayer ReS₂

Precise control of the polarization state of light at the nanoscale is a critical and transformative technology for advancing next-generation nano-optical components. Graphene, despite its highly symmetric lattice and weak in-plane anisotropy, exhibits limited optical response to polarized light in the visible spectrum. This constraint significantly hinders its application in visible-light polarization detection and broader optoelectronic integration. In contrast, two-dimensional (2D) layered rhenium disulfide (ReS₂), characterized by its unique distorted 1T-phase crystal structure, exhibits strong in-plane anisotropy in the visible range. This intrinsic property not only enriches its optical characteristics but also substantially enhances the photocurrent and photoresponsivity of graphene when integrated, thereby offering new opportunities for advanced optoelectronic applications. In this study, we fabricated a vertically stacked graphene/ReS₂ van der Waals heterostructure with high precision. Polarized Raman spectroscopy was employed to systematically analyze the polarization dependence of the heterojunction, enabling an in-depth understanding of its structural and optical anisotropy. Our experimental results reveal that when isotropic single-layer graphene is coupled with anisotropic ReS₂, the resulting heterostructure exhibits anomalous polarization-dependent Raman scattering. This finding highlights the potential of ultrathin 2D heterostructures as nanoscale polarization-sensitive optical elements. This work not only provides a novel approach for designing and implementing next-generation polarization-resolved optical devices based on 2D anisotropic materials but also lays the groundwork for their integration into highly miniaturized and lightweight optoelectronic systems. These findings hold significant promise for advancing the field of optoelectronics and enabling the development of more sophisticated and efficient optical technologies.