DIRECT DETERMINATION OF BAND GAP RENORMALIZATION IN PHOTO-EXCITED MONOLAYER MOS2

Permalink

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

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): 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.
Publisher: International Symposium on Molecular Spectroscopy
Type of Resource: text
Language: English
Permalink: http://hdl.handle.net/2142/104281
DOI: 10.15278/isms.2019.TK03