Interlayer Excitons and Band Alignment in MoS2/hBN/WSe2 van der Waals Heterostructures

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• 作者：Simone LatiniKirsten T. Winther ; Thomas Olsen ; Kristian S. Thygesen
• 刊名：Nano Letters
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：17
• 期：2
• 页码：938-945
• 全文大小：553K
• ISSN：1530-6992

文摘

van der Waals heterostructures (vdWH) are ideal systems for exploring light–matter interactions at the atomic scale. In particular, structures with a type-II band alignment can yield detailed insight into carrier-photon conversion processes, which are central to, for example, solar cells and light-emitting diodes. An important first step in describing such processes is to obtain the energies of the interlayer exciton states existing at the interface. Here we present a general first-principles method to compute the electronic quasi-particle (QP) band structure and excitonic binding energies of incommensurate vdWHs. The method combines our quantum electrostatic heterostructure (QEH) model for obtaining the dielectric function with the many-body GW approximation and a generalized 2D Mott–Wannier exciton model. We calculate the level alignment together with intra- and interlayer exciton binding energies of bilayer MoS<sub>2sub>/WSe<sub>2sub> with and without intercalated hBN layers, finding excellent agreement with experimental photoluminescence spectra. A comparison to density functional theory calculations demonstrates the crucial role of self-energy and electron–hole interaction effects.