Suspended Black Arsenic Nanoribbons with Anisotropic Elastic Properties for Nanomechanical Devices

Anisotropy, as an exotic degree of freedom, enables us to discover emergent two-dimensional (2D) layered nanomaterials with low in-plane symmetry and explore their outstanding properties and promising applications. 2D black arsenic (b-As) with a puckered structure has garnered increasing attention these years owing to its extreme anisotropy with respect to its electrical, thermal, and optical properties. However, investigation on the mechanical properties of 2D b-As is still lacking despite much effort on theoretical simulations. Herein, we report the highly anisotropic elastic properties of suspended b-As nanoribbons via atomic force microscopy-based nanoindentation. It was found that the extracted Young’s modulus of b-As nanoribbons exhibits remarkable anisotropy, which approximates 72.2 ± 5.4 and 44.3 ± 1.4 GPa along zigzag and armchair directions, respectively. The anisotropic ratio reaches up to ∼1.6. We expect that these results could lay a solid foundation for the potential applications of 2D anisotropic nanomaterials in next-generation nanomechanics and optoelectronics.