Role of Photoinduced Exciton in the Transient Terahertz Conductivity of Few-Layer WS2 Laminate

Xiao Xing; Litao Zhao; Zeyu Zhang; Xiankuan Liu; Kailin Zhang; Yang Yu; Xian Lin; Hua Ying Chen; Jin Quan Chen; Zuanming Jin; Jianhua Xu; Guo Hong Ma

doi:10.1021/acs.jpcc.7b05345

Role of Photoinduced Exciton in the Transient Terahertz Conductivity of Few-Layer WS₂ Laminate

Xiao Xing
, Litao Zhao
, Zeyu Zhang
, Xiankuan Liu
, Kailin Zhang
, Yang Yu
, Xian Lin
, Hua Ying Chen
, Jin Quan Chen
, Zuanming Jin^*
, Jianhua Xu
, Guo Hong Ma

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

50 Scopus citations

Abstract

The exciton effect in two-dimensional (2D) transition metal dichalcogenides (TMDs) plays a dominating role in describing the optical and optoelectronic properties. However, the interplay between the excitons and free carriers has not yet been understood upon photoexcitation in 2D TMDs. Here, we first present a study of the dynamical interplay of excitons and unbound electron-hole pairs using time-resolved terahertz (THz) spectroscopy (TRTS) in a few-layer WS₂ laminate. Our experimental results demonstrate that the Auger recombination is observed in the relaxation process of the mobile charge carriers rather than that of excitons upon photoexcitation. The transient complex THz photoconductivity spectroscopy of WS₂ is well described by the Drude-Lorentz model of free carriers modulated by the exciton polarization field. Our results provide a comprehensive understanding of nonequilibrium carrier kinetics (both excitons and free carriers) in WS₂ laminate, and should be applicable to other 2D systems.

Original language	English
Pages (from-to)	20451-20457
Number of pages	7
Journal	Journal of Physical Chemistry C
Volume	121
Issue number	37
DOIs	https://doi.org/10.1021/acs.jpcc.7b05345
State	Published - 21 Sep 2017
Externally published	Yes

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@article{2731de9655254445929943aa961a9db9,

title = "Role of Photoinduced Exciton in the Transient Terahertz Conductivity of Few-Layer WS2 Laminate",

abstract = "The exciton effect in two-dimensional (2D) transition metal dichalcogenides (TMDs) plays a dominating role in describing the optical and optoelectronic properties. However, the interplay between the excitons and free carriers has not yet been understood upon photoexcitation in 2D TMDs. Here, we first present a study of the dynamical interplay of excitons and unbound electron-hole pairs using time-resolved terahertz (THz) spectroscopy (TRTS) in a few-layer WS2 laminate. Our experimental results demonstrate that the Auger recombination is observed in the relaxation process of the mobile charge carriers rather than that of excitons upon photoexcitation. The transient complex THz photoconductivity spectroscopy of WS2 is well described by the Drude-Lorentz model of free carriers modulated by the exciton polarization field. Our results provide a comprehensive understanding of nonequilibrium carrier kinetics (both excitons and free carriers) in WS2 laminate, and should be applicable to other 2D systems.",

author = "Xiao Xing and Litao Zhao and Zeyu Zhang and Xiankuan Liu and Kailin Zhang and Yang Yu and Xian Lin and Chen, \{Hua Ying\} and Chen, \{Jin Quan\} and Zuanming Jin and Jianhua Xu and Ma, \{Guo Hong\}",

note = "Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",

year = "2017",

month = sep,

day = "21",

doi = "10.1021/acs.jpcc.7b05345",

language = "英语",

volume = "121",

pages = "20451--20457",

journal = "Journal of Physical Chemistry C",

issn = "1932-7447",

publisher = "American Chemical Society",

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}

TY - JOUR

T1 - Role of Photoinduced Exciton in the Transient Terahertz Conductivity of Few-Layer WS2 Laminate

AU - Xing, Xiao

AU - Zhao, Litao

AU - Zhang, Zeyu

AU - Liu, Xiankuan

AU - Zhang, Kailin

AU - Yu, Yang

AU - Lin, Xian

AU - Chen, Hua Ying

AU - Chen, Jin Quan

AU - Jin, Zuanming

AU - Xu, Jianhua

AU - Ma, Guo Hong

PY - 2017/9/21

Y1 - 2017/9/21

N2 - The exciton effect in two-dimensional (2D) transition metal dichalcogenides (TMDs) plays a dominating role in describing the optical and optoelectronic properties. However, the interplay between the excitons and free carriers has not yet been understood upon photoexcitation in 2D TMDs. Here, we first present a study of the dynamical interplay of excitons and unbound electron-hole pairs using time-resolved terahertz (THz) spectroscopy (TRTS) in a few-layer WS2 laminate. Our experimental results demonstrate that the Auger recombination is observed in the relaxation process of the mobile charge carriers rather than that of excitons upon photoexcitation. The transient complex THz photoconductivity spectroscopy of WS2 is well described by the Drude-Lorentz model of free carriers modulated by the exciton polarization field. Our results provide a comprehensive understanding of nonequilibrium carrier kinetics (both excitons and free carriers) in WS2 laminate, and should be applicable to other 2D systems.

AB - The exciton effect in two-dimensional (2D) transition metal dichalcogenides (TMDs) plays a dominating role in describing the optical and optoelectronic properties. However, the interplay between the excitons and free carriers has not yet been understood upon photoexcitation in 2D TMDs. Here, we first present a study of the dynamical interplay of excitons and unbound electron-hole pairs using time-resolved terahertz (THz) spectroscopy (TRTS) in a few-layer WS2 laminate. Our experimental results demonstrate that the Auger recombination is observed in the relaxation process of the mobile charge carriers rather than that of excitons upon photoexcitation. The transient complex THz photoconductivity spectroscopy of WS2 is well described by the Drude-Lorentz model of free carriers modulated by the exciton polarization field. Our results provide a comprehensive understanding of nonequilibrium carrier kinetics (both excitons and free carriers) in WS2 laminate, and should be applicable to other 2D systems.

UR - https://www.scopus.com/pages/publications/85029820278

U2 - 10.1021/acs.jpcc.7b05345

DO - 10.1021/acs.jpcc.7b05345

M3 - 文章

AN - SCOPUS:85029820278

SN - 1932-7447

VL - 121

SP - 20451

EP - 20457

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

IS - 37

ER -

Role of Photoinduced Exciton in the Transient Terahertz Conductivity of Few-Layer WS₂ Laminate

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