From Top to Down—Recent Advances in Etching of 2D Materials

Etching, considered as the reverse process of growth, has drawn intensive interests in the past decades. Rather from offering building blocks for formation of materials, etching is served as removing basic units from the matrix. Generally, etching plays a critical role in three aspects: first, it can serve as direct top-down method to precisely make designed patterns for electronic devices. Second, it can offer an indirect way to probe the detailed growth mechanism of 2D materials, enhancing understanding of growth process. Finally, it can be an efficient and facile way to visualize grain boundaries. Herein, several commonly used etching techniques for 2D materials are presented of which chemical vapor deposition etching has attracted the most intensive attentions. Thereafter, the typical etching modes of 2D materials are demonstrated, wherein linear etching, anisotropic etching, and fractal etching are comprehensively exhibited, respectively. Furthermore, the etching mechanism of 2D materials is elucidated, thereby offering a guideline for probing their in-depth etching dynamics and kinetics. Finally, relevant concerns regarding uniformity and reproducibility within etching process are discussed and the expected future is envisaged.