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 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 Subject(s): Mini-symposium: High-Harmonic Generation and XUV Spectroscopy 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. Issue Date: 2019-06-18 Publisher: International Symposium on Molecular Spectroscopy Genre: Conference Paper / Presentation Type: Text Language: English URI: http://hdl.handle.net/2142/104281 DOI: 10.15278/isms.2019.TK03 Rights Information: Copyright 2019 Fang Liu Date Available in IDEALS: 2019-07-152020-01-25
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