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

Liu, Fang

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

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

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