This article is cited in 5 papers

OPTICS AND NUCLEAR PHYSICS

Nonexponential photoluminescence dynamics in an inhomogeneous ensemble of excitons in WSe$_2$ monolayers

M. A. Akmaev^a, M. V. Kochiev^a, A. I. Duleba^ab, M. V. Pugachev^ab, A. Yu. Kuntsevich^a, V. V. Belykh<sup>a

a</sup> Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991 Russia
^b Moscow Institute of Physics and Technology (National Research University), Dolgoprudnyi, Moscow region, 141701 Russia

Abstract: The spectral and spatiotemporal dynamics of photoluminescence in monolayers of transition metal dichalcogenide WSe$_2$ obtained by mechanical exfoliation on a Si/SiO$_2$ substrate is studied over a wide range of temperatures and excitation powers. It is shown that the dynamics is nonexponential and, for times t exceeding $\sim50$ ps after the excitation pulse, is described by a dependence of the form $1/(t + t_0)$. Photoluminescence decay is accelerated with a decrease in the temperature and in the energy of emitting states. It is shown that the observed dynamics cannot be described by a bimolecular recombination process, such as exciton–exciton annihilation. A model that describes the nonexponential photoluminescence dynamics by taking into account the spread of radiative recombination times of localized exciton states in a random potential gives good agreement with experimental data.

Received: 12.10.2020
Revised: 15.10.2020
Accepted: 20.10.2020

DOI: 10.31857/S1234567820220048

 English version: Journal of Experimental and Theoretical Physics Letters, 2020, 112:10, 607–614

Bibliographic databases:

• 
• 
•