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  • Letter
  • Open Access

Ultrafast charge transfer dynamics at the MoS2/Au interface observed via optical spectroscopy under ambient conditions

Tao Yang1,*, Zhipeng Huang1, Stephan Sleziona1, Eckart Hasselbrink2, Peter Kratzer1, Marika Schleberger1, R. Kramer Campen1, and Yujin Tong1,†

  • *Contact author: tao.yang@uni-due.de
  • †Contact author: yujin.tong@uni-due.de
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Phys. Rev. B 114, L051406 – Published 27 July, 2026

DOI: https://doi.org/10.1103/t3fz-gqf9

Abstract

Integrating atomically thin transition metal dichalcogenides (TMDCs) with metallic surfaces is an effective strategy to leverage their exceptional properties in advanced devices and catalysts, as it promotes efficient charge carrier injection and extraction from TMDC monolayers. Light-matter interactions in TMDC monolayers predominantly occur at the K point, making the charge carrier dynamics at this point essential for optimizing charge transfer efficiency. However, direct probing of the dynamics at the K point of TMDCs interfaced with metal substrates remains challenging. In this Letter, we employed pump-probe azimuth- and polarization-dependent final-state sum frequency generation spectroscopy to investigate the ultrafast dynamics of charge transfer at the K point of a MoS2 monolayer on an Au substrate. We observed ultrafast injection of photoexcited hot electrons from Au into the monolayer MoS2 conduction band minimum, followed by a fast return (∼2 ps) and a trap-state-mediated slow return (∼60 ps) processes, driven by an internal electric field. The direct optical observation of the full electron dynamics at the K point of MoS2 monolayer in ambient conditions provides valuable insights into optimizing the transfer of charge carrier across the TMDC/metal interface through optimized contacts, informing the design of advanced TMDC-based devices with enhanced charge transfer rates.

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Phys. Rev. B 114, L051406– Published 27 July, 2026
  • Received 15 January 2025
  • Revised 23 June 2026
  • Accepted 29 June 2026
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