Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.
Phys Chem Chem Phys. 2018 Oct 3;20(38):24726-24734. doi: 10.1039/c8cp03508c.
Recently, van der Waals (vdW) two-dimensional heterostructures have attracted great attention. The combination structures demonstrate unique properties that individual layers do not possess, which foretell promising future applications. Here, we investigate the structural and electronic properties of SiC/graphene, SiC/MoS2, and graphene/SiC/MoS2 vdW heterostructures using first-principles calculations. The SiC/graphene interface forms a p-type Schottky contact, which can be turned into an n-type Schottky contact by applying an external electric field. Moreover, a transition from a Schottky to an Ohmic contact at the interface can be triggered by varying the interlayer distance or applying an external electric field. The SiC/MoS2 interface forms a type-II heterostructure, in which the recombination of photoexcited charges will be greatly suppressed. The transition from type-II to type-III band alignment can be realized in the SiC/MoS2 heterostructure by applying a biaxial strain. This heterostructure also shows excellent optical absorption abilities in the visible and far-infrared range, which merits its application as a photocatalyst. The trilayer heterostructure exhibits a tunable Schottky barrier with different stacking patterns and the assembled graphene could act as a protective encapsulating layer on SiC/MoS2. The results show that graphene and MoS2 can tune and improve the electronic performance of SiC and demonstrate the promising application of SiC-based heterostructures for nanoelectronics and nanophotonics.
最近，范德华（vdW）二维异质结构引起了极大的关注。组合结构表现出单个层所不具备的独特性质，预示着有前途的未来应用。在这里，我们使用第一性原理计算研究了 SiC/石墨烯、SiC/MoS2 和石墨烯/SiC/MoS2 vdW 异质结构的结构和电子性质。SiC/石墨烯界面形成 p 型肖特基接触，通过施加外部电场可以将其转变为 n 型肖特基接触。此外，通过改变层间距离或施加外部电场，可以触发界面处从肖特基接触到欧姆接触的转变。SiC/MoS2 界面形成 II 型异质结，其中光激发电荷的复合将大大抑制。通过施加双轴应变，可以在 SiC/MoS2 异质结构中实现从 II 型到 III 型能带排列的转变。这种异质结构在可见光和远红外范围内也表现出优异的光吸收能力，这使其有望作为光催化剂应用。三层异质结构具有可调谐的肖特基势垒，具有不同的堆叠模式，组装的石墨烯可以作为 SiC/MoS2 的保护性封装层。结果表明，石墨烯和 MoS2 可以调整和改善 SiC 的电子性能，并展示了基于 SiC 的异质结构在纳米电子学和纳米光子学中的有前途的应用。
