Evidence for the Dominance of Carrier-Induced Band Gap Renormalization over Biexciton Formation in Cryogenic Ultrafast Experiments on MoS2 Monolayers

Ryan E. Wood, Lawson T. Lloyd, Fauzia Mujid, Lili Wang, Marco A. Allodi, Hui Gao, Richard Mazuski, Po Chieh Ting, Saien Xie, Jiwoong Park, Gregory S. Engel

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Transition-metal dichalcogenides (TMDs) such as MoS2 display promising electrical and optical properties in the monolayer limit. Due to strong quantum confinement, TMDs provide an ideal environment for exploring excitonic physics using ultrafast spectroscopy. However, the interplay between collective excitation effects on single excitons such as band gap renormalization/exciton binding energy (BGR/EBE) change and multiexciton effects such biexciton formation remains poorly understood. Using two-dimensional electronic spectroscopy, we observe the dominance of single-exciton BGR/EBE signals over optically induced biexciton formation. We make this determination based on a lack of strong PIA features at T = 0 fs in the cryogenic spectra. By means of nodal line slope analysis, we determine that spectral diffusion occurs faster than BGR/EBE change, indicative of distinct processes. These results indicate that at higher sub-Mott limit fluences, collective effects on single excitons dominate biexciton formation.

Original languageEnglish (US)
Pages (from-to)2658-2666
Number of pages9
JournalJournal of Physical Chemistry Letters
Volume11
Issue number7
DOIs
StatePublished - Apr 2 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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