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

Simone Latini, Kirsten Trøstrup Winther, Thomas Olsen, Kristian Sommer Thygesen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

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 MoS2/WSe2 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.
Original languageEnglish
JournalNano letters
Volume17
Issue number2
Pages (from-to)938-945
Number of pages8
ISSN1530-6984
DOIs
Publication statusPublished - 2017

Keywords

  • van der Waals heterostructures
  • interlayer excitons
  • band alignment
  • G0W0
  • Mott−Wannier model

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