Transport Dynamics of Neutral Excitons and Trions in Monolayer WS 2

Understanding the spatial motion of excitons is of both fundamental interest and central importance for optoelectrical applications. Here, we have investigated the temperature (T) dependence of the transport dynamics of neutral excitons and charged excitons (trions) in atomically thin two-dimensiona...

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Bibliographic Details
Published inACS nano Vol. 10; no. 10; pp. 9687 - 9694
Main Authors Kato, Toshiaki, Kaneko, Toshiro
Format Journal Article
LanguageEnglish
Published United States 25.10.2016
Subjects
transport dynamics
excitons
temperature dependence
photoluminescence
WS2
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Summary:Understanding the spatial motion of excitons is of both fundamental interest and central importance for optoelectrical applications. Here, we have investigated the temperature (T) dependence of the transport dynamics of neutral excitons and charged excitons (trions) in atomically thin two-dimensional crystals of the transition-metal dichalcogenide WS . The transport dynamics of neutral excitons can be divided into three temperature ranges, where the diffusion of neutral excitons is governed by thermal activation (≤∼75 K), ionized impurity scattering (∼75 K ≤ T ≤∼200 K), and LO phonon scattering (≥∼200 K). The trions have a diffusion length that is over 20 times longer than that of neutral excitons at very low temperatures (≤∼10 K), which may be related to theoretically predicted Pauli-blocking effects during the excitation process.
ISSN:1936-0851
1936-086X
DOI:10.1021/acsnano.6b05580