Anisotropic Mechanical Properties of Black Phosphorus Nanoribbons

The mechanical properties of black phosphorus (BP) nanoribbons suspended on narrow grooves are quantitatively investigated with the nanoindentation method on the basis of atomic force microscopy. The elastic moduli of BP nanoribbons are strongly related to the included angle between the lattice orientation and the groove. A theoretical model based on classical elasticity theory is established to explain the directional elastic modulus and matches well with the experimental results. The ideal elastic modulus of zigzag and armchair BP nanoribbons are about 65 and 27 GPa, respectively, and this agrees with the simulation results obtained by theoretical calculations. The obtained results in the present investigations strengthen the understanding of the fascinating anisotropic properties of BP, which would be of great help for future application of BP in flexible electronics, nanoelectromechanical systems, etc.