Patterning two-dimensional semiconductors with thermal etching

The controllable synthesis of complicated nanostructures in advanced two- dimensional (2D) semiconductors, such as periodic regular hole arrays, is essential and remains immature. Here, we report a green, facile, highly controlled synthetic method to efficiently pattern 2D semiconductors, such as periodic regular hexagonal- shaped hole arrays (HHA), in 2D- TMDs. Combining the production of artificial defect arrays through laser irradiation with anisotropic annealing etching, we created HHA with different arrangements, controlled hole sizes, and densities in bilayer WS2. Atomic force microscopy (AFM), Raman, photoluminescence ( PL), and scanning transmission electron microscopy (STEM) characterization show that the 2D semiconductors have high quality with atomical clean and sharp edges as well as undamaged crystals in the unetched region. Furthermore, other nanostructures, such as nanoribbons and periodic regular triangular-shaped 2D-TMD arrays, can be fabricated. This kind of 2D semiconductors fabrication strategy is general and can be extended to a series of 2D materials. Density functional theory (DFT) calculations show that one WS2 molecule from the edges of the laser-irradiated holed region exhibits a robust etching activation, making selective etching at the artificial defects and the fabrication of regular 2D semiconductors possible.