In-situ fabrication of Mo₆S₆-nanowire-terminated edges in monolayer molybdenum disulfide

Edge structures are highly relevant to the electronic, magnetic, and catalytic properties of two-dimensional (2D) transition metal dichalcogenides (TMDs) and their one-dimensional (1D) counterparts, i.e., nanoribbons, and should be precisely tailored for the desired application. In this work, we report the formation of novel Mo₆S₆ nanowire (NW)-terminated edges in monolayer molybdenum disulfide (MoS₂) via an e–beam irradiation process combined with high temperature heating. The atomic structures of the NW-terminated edges and the dynamic formation process were observed experimentally using scanning transmission electron microscopy. Further analysis showed that the NW-terminated edge could be formed on both the Mo-zigzag (ZZ) edge and S-ZZ edge and could exhibit a stability superior to that of the pristine ZZ and armchair (AC) edges. In addition, analogous edge structures could also be formed in MoS₂ nanoribbons and other TMD materials such as Mo_xW_1-xSe₂. We believe that these novel edge structures may impart novel properties to the 2D and 1D TMD materials and provide new opportunities for their applications in catalytic, spintronic, and electronic devices.