Super-Resolution Nanolithography of Two-Dimensional Materials by Anisotropic Etching

Nanostructuring allows altering of the electronic and photonic properties two-dimensional (2D) materials. The efficiency, flexibility, convenience top-down lithography processes are however compromised by nm-scale edge roughness resolution variability issues, which especially affects performance 2D Here we study how dry anisotropic etching multilayer materials with sulfur hexafluoride (SF6) may overcome some these showing results for hexagonal boron nitride (hBN), tungsten disulfide (WS2), diselenide (WSe2), molybdenum (MoS2), ditelluride (MoTe2). Scanning transmission electron microscopy reveal that leads to features in studied transition metal dichalcogenides, relative degree anisotropy ranked as: WS2 > WSe2 MoTe2 / MoS2. Etched holes terminated zigzag edges while etched dots (protrusions) armchair edges. This can be explained Wulff constructions, taking stabilities AA stacking order into account. Patterns transferred an underlying graphite layer, demonstrating a possible use creating sub-10 nm features. In contrast, hBN exhibits no lateral anisotropy, but shows consistent vertical etch angles, independent crystal orientation. is used create super-resolution lithographic patterns ultra-sharp corners at base crystal, crystal. We find SF6 reactive ion process makes it downsize nanostructures obtain smooth edges, sharp corners, feature sizes significantly below limit beam lithography. nanostructured themselves or as etch-masks pattern other nanomaterials.