  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) counterpart, i.e., nanoribbons, which should be
precisely tailored for the desirable applications. In this work, we report the
formation of novel Mo6S6 nanowire (NW) terminated edges in a monolayer
molybdenum disulfide (MoS2) via an e-beam irradiation process combined with
high temperature heating in a scanning transmission electron microscope (STEM).
Atomic structures of NW terminated edges and the dynamic formation process were
observed experimentally. Further analysis shows that NW terminated edge could
form on both Mo-zigzag (ZZ) edge and S-ZZ edge which can exhibit even higher
stability superior to the pristine zigzag (ZZ) and armchair (AC) edge. In
addition, the analogous edge structures can be also formed in MoS2 nanoribbon
and other TMDs material such as MoxW1-xSe2. We believe that the presence of
these novel edge structures in 2D and 1D TMD materials may provide novel
properties and new opportunities for their versatile applications including
catalytic, spintronic and electronic devices.
