LAUSR

As the most remarkable candidate for the next-generation electronics, two-dimensional (2D) materials have attracted much interest. Recently in a letter in Nature Materials, Professor David A. Muller and Lain-Jong Li and their cooperators reported the direct synthesis of one-dimensional (1D) MoS2 channels embedded in 2D WSe2 monolayers through a dislocation-catalyzed strategy [1]. They demonstrated that 1D MoS2 channels of subnanometer widths were formed in the second-step of a two-step chemical vapor deposition (CVD) growth of the lateral WSe2/MoS2 heterostructures. The root cause lies in the exposure of the as-generated 5|7 member ring dislocations along the sharp grain boundaries or implanted in WSe2 to the Mo and S atmosphere. Through atomic resolution annular dark-field scanning transmission electron microscopy (ADF-STEM) and molecular dynamics (MD) simulations, a conclusion was drawn that the higher reactivity in the core of the misfit dislocations induced the insertion of Mo and S atoms and such dislocations were pushed away from the ordinary dislocations to form 1D channels (Fig. 1). Moreover, a 1D MoS2 nanowire of ~1 nm long could be obtained from the periodic dislocation along the boundary of two WSe2 grains. The work could provide with the inspiration of the synthesis of 1D channels based on the substrate of defects. That is, different channels based on 2D materials could be fabricated through chemical methods which prevent from the impurities caused by lithography. It is essential for a device to simplify the constructing process in order to reduce the introduction of impurities. According to this work, the substrate design is critical to the material fabrication. Till now, plenty of substrate-designing strategies have been generally utilized to fabricate nanostructured 2D materials or superlattices. Here, the substrates refer not only to metals, SiO2/Si, mica, sapphire, but also to edges, grains or even defects of 2D materials. Thus, CVD growth for the synthesis of nanostructured 2D materials and superlattices lies most on the substrate designing. There have been a series of methods to design metal or non-