1s-intraexcitonic dynamics in monolayer MoS2 probed by ultrafast mid-infrared spectroscopy

Soonyoung Cha, Ji Ho Sung, Sangwan Sim, Jun Park, Hoseok Heo, Moon Ho Jo, Hyunyong Choi

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The 1s exciton - the ground state of a bound electron-hole pair - is central to understanding the photoresponse of monolayer transition metal dichalcogenides. Above the 1s exciton, recent visible and near-infrared investigations have revealed that the excited excitons are much richer, exhibiting a series of Rydberg-like states. A natural question is then how the internal excitonic transitions are interrelated on photoexcitation. Accessing these intraexcitonic transitions, however, demands a fundamentally different experimental tool capable of probing optical transitions from 1s 'bright' to np 'dark' states. Here we employ ultrafast mid-infrared spectroscopy to explore the 1s intraexcitonic transitions in monolayer MoS2. We observed twofold 1s→3p intraexcitonic transitions within the A and B excitons and 1s→2p transition between the A and B excitons. Our results revealed that it takes about 0.7 ps for the 1s A exciton to reach quasi-equilibrium; a characteristic time that is associated with a rapid population transfer from the 1s B exciton, providing rich characteristics of many-body exciton dynamics in two-dimensional materials.

Original languageEnglish
Article number10768
JournalNature communications
Volume7
DOIs
Publication statusPublished - 2016 Feb 25

Fingerprint

Infrared spectroscopy
Monolayers
Spectrum Analysis
infrared spectroscopy
excitons
Optical transitions
LDS 751
Photoexcitation
photoexcitation
optical transition
Ground state
Transition metals
Metals
transition metals
Electrons
Infrared radiation
ground state
Population

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Cha, Soonyoung ; Sung, Ji Ho ; Sim, Sangwan ; Park, Jun ; Heo, Hoseok ; Jo, Moon Ho ; Choi, Hyunyong. / 1s-intraexcitonic dynamics in monolayer MoS2 probed by ultrafast mid-infrared spectroscopy. In: Nature communications. 2016 ; Vol. 7.
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1s-intraexcitonic dynamics in monolayer MoS2 probed by ultrafast mid-infrared spectroscopy. / Cha, Soonyoung; Sung, Ji Ho; Sim, Sangwan; Park, Jun; Heo, Hoseok; Jo, Moon Ho; Choi, Hyunyong.

In: Nature communications, Vol. 7, 10768, 25.02.2016.

Research output: Contribution to journalArticle

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AU - Jo, Moon Ho

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