Direct Determination of Band Gap Renormalization in Photo-Excited Monolayer MoS2

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 (Eb) and strong renormalization of the quasiparticle bandgap (Eg) by carriers. The latter has been difficult to determine due to cancellation in changes of Eb and Eg, resulting in little change in optical transition energy at different carrier densities. Here we quantify bandgap renormalization in macroscopic single crystal MoS2 monolayers on SiO2 using time and angle resolved photoemission spectroscopy (TR-ARPES). At excitation density above the Mott threshold, Eg decreases by as much as 360 meV. We compare the carrier density dependent Eg with previous theoretical calculations and show the necessity of knowing both doping and excitation densities in quantifying the bandgap.

20 pages

References in corpus (7)

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Cited by in corpus (2)

• Towards full surface Brillouin zone mapping by coherent multi-photon photoemission
• Many-body exchange-correlation effects in MoS${}_2$ monolayer: The key role of nonlocal dielectric screening