Template-guided stacking regulation and morphology evolution of multilayer 2H- and 3R-WS₂ during layer-by-layer epitaxy

Two-dimensional layered materials have attracted extensive interest owing to their highly tunable electronic and optoelectronic properties associated with layer number and interlayer stacking. Tungsten disulfide (WS₂), a representative transition metal dichalcogenide, mainly adopts 2H and 3R stacking configurations in multilayer form, which exhibit distinct crystal symmetries and nonlinear optical responses. However, how template-guided stacking evolution influences the layer and morphology evolution of multilayer WS₂ during layer-by-layer epitaxy remains insufficiently understood. Herein, we demonstrate a WS₂-template-guided van der Waals epitaxial strategy to regulate the stacking propagation pathways and morphology evolution of multilayer WS₂. Under the combined effects of template-guided epitaxial regulation and deposition-temperature-dependent stacking evolution, distinct stacking propagation pathways preferentially lead to AB-stacked 2H-WS₂ and ABC-stacked 3R-WS₂. Notably, multilayer 2H-WS₂ exhibits asynchronous layer-dependent morphology evolution from triangular to hexagonal tower-like structures, whereas 3R-WS₂ maintains a self-similar pyramidal growth pathway with highly ordered stacking propagation. Atomic force microscopy (AFM) and second harmonic generation (SHG) mapping further establish the intrinsic correlation among stacking evolution, layer evolution, morphology evolution, and symmetry response in multilayer WS₂, including odd-even SHG oscillation in 2H-WS₂ and progressively enhanced SHG response in multilayer 3R-WS₂. These findings provide new insights into template-guided stacking regulation during multilayer van der Waals epitaxy, offering a potential strategy for the controllable structural engineering of layered transition metal dichalcogenide materials.