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Sabrine Ayari: Low-temperature dynamics of free and localized excitons in Transition metal dichalcogenides (TMDs)

posted 12 Aug 2019, 04:35 by info admin   [ updated 12 Aug 2019, 10:07 ]
Sabrine Ayari,*a and Sihem Jaziri*a,b
aFaculté des Sciences de Bizerte, Laboratoire de Physique des MatériauxLaboratoire de Physique des Materiaux: Structure et Propriétés,  Université de Carthage,7021 Jarzouna, Tunisia 
.*E-mail: sabrineayaari8@gmail.com 
bFaculté des Sciences de Tunis, Laboratoire de Physique de la MatièreCondensée,Département de Physique, Université Tunis el Manar,  Campus Universitaire 2092 Tunis, Tunisia 
*E-mail: sihem.jaziri@fsb.rnu.tn

Disorder derived from defects or local strain in monolayer transition-metal dichalcogenides (TMDs) can lead to a dramatic change in the physical behavior of the interband excitations, producing inhomogeneous spectral broadening and localization leading to radiative lifetime increase [1,2]. In this study, we have modeled the surface disorder of a monolayer TMD sample through a randomized potential in the layer plane. We give an in depth study of the influence of the disorder potential parameters on the optical properties of these defects through energies, density of states, oscillator strengths, and radiative lifetime at low temperature (4 K) [1]. We demonstrate that localized excitons have a longer emission time than free excitons, in the range of tens of picoseconds or more [2]. Finally, in order to prove the validity of our model, we compare it to available experimental results of the literature. 

[1] S. Ayari, A. Smiri, A. Hichri, S. Jaziri, T. Amand, Phys. Rev. B, 98, 4 205430 (2018)
[2] S. Ayari and S. Jaziri, Phys. Status Solidi B, 1800682 (2019)

Sabrine Ayari is currently a phd student of Physics at the university of Carthage Tunisia, Faculty of science of Bizerte. She received her masters degree in physics from faculty of science of Bizerte. She spent 7 month internship in Institute of Optics and Atomic Physics in “ Technische Universität Berlin” . She have 4 published articles.