The role of momentum-dark excitons in the elementary optical response of bilayer WSe2
Journal article, 2018

Monolayer transition metal dichalcogenides (TMDs) undergo substantial changes in the single-particle band structure and excitonic optical response upon the addition of just one layer. As opposed to the single-layer limit, the bandgap of bilayer (BL) TMD semiconductors is indirect which results in reduced photoluminescence with richly structured spectra that have eluded a detailed understanding to date. Here, we provide a closed interpretation of cryogenic emission from BL WSe2as a representative material for the wider class of TMD semiconductors. By combining theoretical calculations with comprehensive spectroscopy experiments, we identify the crucial role of momentum-indirect excitons for the understanding of BL TMD emission. Our results shed light on the origin of quantum dot formation in BL crystals and will facilitate further advances directed at opto-electronic applications of layered TMD semiconductors in van der Waals heterostructures and devices.

Author

Jessica Lindlau

Ludwig-Maximilians-Universität München

Malte Selig

Chalmers, Physics, Condensed Matter Theory

Technische Universität Berlin

Andre Neumann

Ludwig-Maximilians-Universität München

Léo Colombier

Ludwig-Maximilians-Universität München

Jonathan Förste

Ludwig-Maximilians-Universität München

Victor Funk

Ludwig-Maximilians-Universität München

Michael Förg

Ludwig-Maximilians-Universität München

Jonghwan Kim

University of California

Gunnar Berghäuser

Chalmers, Physics, Condensed Matter Theory

Takashi Taniguchi

National Institute for Materials Science (NIMS)

Kenji Watanabe

National Institute for Materials Science (NIMS)

Feng Wang

University of California

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

Alexander Högele

Ludwig-Maximilians-Universität München

Nature Communications

2041-1723 (ISSN)

Vol. 9 1 2586

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics

DOI

10.1038/s41467-018-04877-3

More information

Latest update

9/19/2018