Fig. 2. Formation of periodic dislocation arrays and dislocation-driven growth of WS₂ quantum wells at the WSe₂/WS₂ lateral interface.

(A) Schematic showing (I) the formation of periodic dislocation array, (II) dislocation-driven growth of WS₂ quantum wells, and (III) formation of 2D quantum-well superlattice in the WSe₂/WS₂ lateral heterostructure. (B) STEM-ADF image of a WSe₂/WS₂ lateral interface without the formation of WS₂ quantum wells. The epitaxial interface is highlighted by the yellow dashed line. (C) Corresponding strain distribution, overlaid onto the ADF image, showing the formation of periodic dislocation array at the heterointerface. (D) STEM-ADF image of a WSe₂/WS₂ lateral interface with the formation of WS₂ quantum wells. The WS₂ quantum wells appear as darker stripes with the same width. (E) Corresponding strain map, overlaid onto the ADF image, showing the presence of a dislocation core at the tip of each WS₂ quantum well. Insets in (C) and (E) are magnified views of the strain maps at the highlighted dislocation cores.