Since the discovery of graphene, van der Waals (vdW) two-dimensional (2D) materials have attracted considerable attention for various potential applications. Recently, a Se-terminated bismuth oxychalcogenide, Bi2O2Se, has been fabricated using the vapor deposition method. Bi2O2Se is not a vdW 2D material, but the as-grown substance shows 2D characteristics. For example, Bi2O2Se exhibits layer number-dependent absorption spectra in experiments, but until now, there has been no reasonable explanation as to why. Here, we propose a 50% Se-passivation surface model, which elucidates the production of such spectra. Our model is also consistent with recent observations using scanning tunneling microscopy. Moreover, high-resolution transmission electron microcopy observations show a broken zipper-like structure in Bi2O2Se. We ascribe Bi2O2Se as a zipper 2D material, and we summarize the characteristics of zipper 2D materials while proposing the development of others. Zipper 2D materials not only are an important subset of 2D materials but also bridge the gap between vdW 2D materials and traditional 3D materials. Because they are a big family, including insulators, semiconductors, and magnetic metals, zipper 2D materials lend themselves to a plethora of applications.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Oct 17 2019|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the National Natural Science Foundation of China (nos. 61575094 and 91833302). This work was also sponsored by Qing Lan Project and the Jiangsu Specially-Appointed Professor program. We are grateful to the High Performance Computing Center of Nanjing Tech University for supporting the computational resources.