Large-Area Aligned Growth of Low-Symmetry 2D ReS 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 (ReS), 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 ReS 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 ReS flakes are guided by step edges on Au(111) surfaces along the [011̅] direction. Additionally, 2D ReS can flatten Au surfaces during its growth through surface step bunching. The growth of the ReS 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 ReS significantly contributes to the in-depth understanding of epitaxial growth mechanisms for low-symmetry 2D materials, holding promise for advancing their future applications.