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Regarding the reverse process of materials growth, etching has been widely concerned to indirectly probe the growth kinetics, offering an avenue in governing the growth of two-dimensional (2D) materials. In this work, interface-driven anisotropic etching mode is demonstrated for the first time to be generally applied to 2D heterostructures. It is shown that the typical in-plane graphene and hexagonal boron nitride (h-BN) heterostructures follow a multi-stage etching behavior initiated first along the interfacial region between the two materials and then along edges of neighboring h-BN flakes and finally along central edges of h-BN. By accurately tuning etching conditions in the chemical vapor deposition process, series of etched 2D heterostructure patterns are controllably produced. Furthermore, scaled formation of graphene and h-BN heterostructures arrays has been realized with full assist of as-proposed etching mechanism, offering a direct top-down method to make 2D orientated heterostructures with order and complexity. Detection of interface-driven multi-staged anisotropic etching mode will shed light on understanding growth mechanism and further expanding wide applications of 2D heterostructures. [ABSTRACT FROM AUTHOR]

Graphene with atomically smooth and configuration-specific edges plays the key role in the performance of graphene-based electronic devices. Remote hydrogen plasma etching of graphene has been proven to be an effective way to create smooth edges with a specific zigzag configuration. However, the etching process is still poorly understood. In this study, with the aid of a custom-made plasma-enhanced hydrogen etching (PEHE) system, a detailed graphene etching process by remote hydrogen plasma is presented. Specifically, we find that hydrogen plasma etching of graphene shows strong thickness and temperature dependence. The etching process of single-layer graphene is isotropic. This is opposite to the anisotropic etching effect observed for bilayer and thicker graphene with an obvious dependence on temperature. On the basis of these observations, a geometrical model was built to illustrate the configuration evolution of graphene edges during etching, which reveals the origin of the anisotropic etching effect. By further utilizing this model, armchair graphene edges were also prepared in a controlled manner for the first time. These investigations offer a better understanding of the etching process for graphene, which should facilitate the fabrication of graphene-based electronic devices with controlled edges and the exploration of more interesting properties of graphene. [ABSTRACT FROM AUTHOR]