Large-Area Aligned Growth of Low-Symmetry 2D ReS₂ on a High-Symmetry Surface

The large-scale preparation of two-dimensional (2D) materials is pivotal in unlocking their extensive potential for next-generation semiconductor device applications. Wafer-scale single crystals of a high-symmetry 2D material (e.g., graphene and molybdenum disulfide) can be achieved by seamlessly stitching the aligned domains. However, achieving the alignment of low-symmetry 2D materials remains a great challenge and is rarely reported. Rhenium disulfide (ReS₂), one of the low-symmetry 2D materials, shows considerable promise for optoelectronics, especially polarization-sensitive applications. Here, we report large-area chemical vapor deposition synthesis of highly oriented, low-symmetry monolayer ReS₂ flakes on a high-symmetry Au(111) surface, followed by seamless stitching into a centimeter-scale continuous 2D film. Cross-sectional scanning transmission electron microscopy reveals that the aligned monolayer ReS₂ flakes are guided by step edges on Au(111) surfaces along the [011̅] direction. Additionally, 2D ReS₂ can flatten Au surfaces during its growth through surface step bunching. The growth of the ReS₂ monolayer demonstrates its ability to extend across Au surface steps and facets. Thus, we have established a reliable and robust synthesis route that accommodates different surface roughness conditions. The aligned and scalable film growth of low-symmetry 2D ReS₂ significantly contributes to the in-depth understanding of epitaxial growth mechanisms for low-symmetry 2D materials, holding promise for advancing their future applications.