Four vertical heterostructures based on two-dimensional transition-metal dichalcogenides (TMDs) – MoS/GeC, MoSe/GeC, WS/GeC, and WSe/GeC, were studied by density functional theory calculations to investigate their structure, electronic characteristics, principle of photogenerated electron–hole separation, and optical-absorption capability. The optimized heterostructures were formed by van der Waals (vdW) forces and without covalent bonding. Their most stable geometric configurations and band structures display type-II band alignment, which allows them to spontaneously separate photogenerated electrons and holes. The charge difference and built-in electric field across the interface of these vdW heterostructures also contribute to preventing the photogenerated electron–hole recombination. Finally, the high optical absorption of the four TMD-based vdW heterostructures in the visible and near-infrared regions indicates their suitability for photocatalytic, photovoltaic, and optical devices.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the Transformation project of scientific and technological achievements of JiangSu (BA2015077), National Natural Science Foundation of China (51675100), National Science and Technology Major Projects of Numerical control equipment (2016ZX04004008), the Innovation Project Foundation of Southeast University (3202008708), the National Science Foundation for Young Scientists of China (11704165) and the Science Foundation of Jinling Institute of Technology (40620064).