University of Illinois Urbana-Champaign

Direct determination of band gap renormalization in photo-excited monolayer MoS2

Liu, Fang

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1403775.pptx
3825.pdf

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https://hdl.handle.net/2142/104281

Description

Title
Direct determination of band gap renormalization in photo-excited monolayer MoS2
Author(s)
Liu, Fang
Contributor(s)
  • Zhu, Xiaoyang
  • Wang, Jue
  • Hansen, Kameron R.
  • Ziffer, Mark E.
Issue Date
2019-06-18
Keyword(s)
High-harmonic generation and XUV spectroscopy
Date of Ingest
  • 2019-07-15T22:16:34Z
  • 2020-01-25T19:30:48Z
Abstract
A key feature of monolayer semiconductors, such as transition-metal dichalcogenides, is the poorly screened Coulomb potential, which leads to large exciton binding energy (E$_{b}$) and strong renormalization of the quasiparticle bandgap (E$_{g}$) by carriers. The latter has been difficult to determine due to cancellation in changes of E$_{b}$ and E$_{g}$, resulting in little change in optical transition energy at different carrier densities. Here we quantify bandgap renormalization in macroscopic single crystal \chem{MoS_2} monolayers on \chem{SiO_2} using time and angle resolved photoemission spectroscopy (TR-ARPES) with femtosecond extreme UV (EUV) probe. At excitation density above the Mott threshold, E$_{g}$ decreases by as much as 360 meV. We compare the carrier density dependent E$_{g}$ with previous theoretical calculations and show the necessity of knowing both doping and excitation densities in quantifying the bandgap.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/104281
DOI
https://doi.org/10.15278/isms.2019.TK03
Copyright and License Information
Copyright 2019 Fang Liu

Owning Collections

Abstracts & Presentations - 2019 International Symposium on Molecular Spectroscopy PRIMARY