Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers
Journal article, 2019

© 2019 The Royal Society of Chemistry. The reduced dielectric screening in atomically thin transition metal dichalcogenides allows to study the hydrogen-like series of higher exciton states in optical spectra even at room temperature. The width of excitonic peaks provides information about the radiative decay and phonon-assisted scattering channels limiting the lifetime of these quasi-particles. While linewidth studies so far have been limited to the exciton ground state, encapsulation with hBN has recently enabled quantitative measurements of the broadening of excited exciton resonances. Here, we present a joint experiment-theory study combining microscopic calculations with spectroscopic measurements on the intrinsic linewidth and lifetime of higher exciton states in hBN-encapsulated WSe2 monolayers. Surprisingly, despite the increased number of scattering channels, we find both in theory and experiment that the linewidth of higher excitonic states is similar or even smaller compared to the ground state. Our microscopic calculations ascribe this behavior to a reduced exciton-phonon scattering efficiency for higher excitons due to spatially extended orbital functions.

Author

Samuel Brem

Chalmers, Physics, Condensed Matter Theory

Jonas Zipfel

University of Regensburg

M. Selig

Technische Universität Berlin

A. Raja

University of California

Lutz Waldecker

Stanford University

Jonas D. Ziegler

University of Regensburg

Takashi Taniguchi

National Institute for Materials Science (NIMS)

Kenji Watanabe

National Institute for Materials Science (NIMS)

A. Chernikov

University of Regensburg

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

Nanoscale

2040-3364 (ISSN)

Vol. 11 25 12381-12387

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics

DOI

10.1039/c9nr04211c

More information

Latest update

10/14/2019