Electronic and optical properties of van der Waals vertical heterostructures based on two-dimensional transition metal dichalcogenides: First-principles calculations

Publication date: Available online 1 February 2019Source: Physics Letters AAuthor(s): Kai Ren, Minglei Sun, Yi Luo, Sake Wang, Yujing Xu, Jin Yu, Wencheng TangAbstractFour vertical heterostructures based on two-dimensional transition-metal dichalcogenides (TMDs) – MoS2/GeC, MoSe2/GeC, WS2/GeC, and WSe2/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.

Source: Physics Letters A - February 2, 2019 Category: Physics Source Type: research