Tunable-Diameter Nanoscrolls from Janus WSSe/WSe₂ Heterostructures

Janus transition metal dichalcogenide (TMD) nanoscrolls have recently emerged as promising nanostructures for studying curvature- and chirality-dependent physical phenomena. However, systematic strategies to fabricate multilayer Janus TMD nanoscrolls with controlled diameters and to probe their structure-dependent optical behaviors are still lacking. Expanding on the previous finding that Janus TMD monolayers─with intrinsic asymmetry and built-in strain─spontaneously form nanoscrolls, we now demonstrate diameter-tunable nanoscrolls derived from Janus WSSe/WSe2 heterostructures. The incorporation of a Janus monolayer facilitates the scrolling of heterostructures and enables continuous tuning of nanoscroll diameters across a broad range─from ∼10 nm to ∼1 μm. The resulting structures exhibit uniform crystallinity and composition, as confirmed by scanning transmission electron microscopy. Optical characterizations reveal anisotropic Raman responses and strain-induced modulation of second-harmonic generation (SHG). These results indicate that Janus-based nanoscrolls provide a versatile platform for investigating structure–property relationships and developing rolled TMD systems for advanced photonic and optoelectronic applications.