Chemically Derived Kirigami of WSe2

Layered metal dichalcogenides have shown intriguing physical phenomena depending on their complex layer stackings and unique architectures. Here, we report novel microscale kirigami structures of multilayered WSe2 formed by a simple chemical vapor deposition and etching method. Scanning electron microscopy and atomic force microscopy reveal the unusual structure features of curved concave edges, panhandles, and sawtooth corners of these intricate multilayer architectures that result from etching. The structure-symmetry relationship and layer stackings of these WSe2 kirigami were elucidated by second-harmonic generation imaging and micro-Raman spectroscopy. We propose an etching model in which the etching behaviors of WSe2 multilayers are governed by the layer stacking of the bottom trilayer, which can successfully explain the formation process of WSe2 kirigami. This chemical etching approach could be applied to other metal dichalcogenide materials and open up new possibilities for creating novel and complex platforms for studying the rich physical properties in two-dimensional materials.