Ultrafast Recombination Dynamics under Lateral Confinement and Cryogenic Temperatures in Colloidal MoS₂

verfasst von

André Philipp Frauendorf, André Niebur, Dominik Rudolph, Michael Oestreich, Jannika Lauth, Jens Hübner

Abstract

Colloidal synthesis opened up a versatile way to tailor two-dimensional transition metal dichalcogenides. In particular, the huge oscillator strength of excitons in colloidal MoS₂ makes the material appealing for excitonic devices. In this context, we studied ultrafast excitons with transient absorption (TA) spectroscopy in MoS₂ nanosheets (NSs, 22 ± 9 nm) and nanoplatelets (NPLs, 8 ± 4 nm) with NPLs providing additional lateral confinement of excitons in the structures. Carrier relaxation mechanisms are identified by extending the TA setup with a custom micro cryostat and by extracting time-dependent line shapes. The exciton lifetime in MoS₂ NSs almost doubles from 12 to 22 ps by cooling the samples from 295 to 9 K, which is attributed to phonon scattering. Temperature-dependent recombination dynamics are found for the sparsely studied C and D excitons, thus covering the full visible spectrum by time-resolved characterization. For smaller MoS₂ NPLs, the A exciton signature reappears at cryogenic temperatures, allowing laterally confined excitons in MoS₂ to be extensively studied for the first time.

Organisationseinheit(en)

Institut für Festkörperphysik
Institut für Physikalische Chemie und Elektrochemie
PhoenixD: Simulation, Fabrikation und Anwendung optischer Systeme
Laboratorium für Nano- und Quantenengineering

Externe Organisation(en)

Eberhard Karls Universität Tübingen

Typ

Artikel

Journal

Journal of Physical Chemistry C

Band

128

Seiten

16597–16606

Anzahl der Seiten

10

ISSN

1932-7447

Publikationsdatum

03.10.2024

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Elektronische, optische und magnetische Materialien, Energie (insg.), Physikalische und Theoretische Chemie, Oberflächen, Beschichtungen und Folien

Elektronische Version(en)

https://doi.org/10.1021/acs.jpcc.4c04581 (Zugang: Offen)