Weak Distance Dependence of Hot-Electron-Transfer Rates at the Interface between Monolayer MoS2and Gold

Ce Xu, Hui Wen Yong, Jinlu He, Run Long, Alisson R. Cadore, Ioannis Paradisanos, Anna K. Ott, Giancarlo Soavi, Sefaattin Tongay, Giulio Cerullo, Andrea C. Ferrari, Oleg V. Prezhdo, Zhi Heng Loh

Research output: Contribution to journalArticlepeer-review

Abstract

Electron transport across the transition-metal dichalcogenide (TMD)/metal interface plays an important role in determining the performance of TMD-based optoelectronic devices. However, the robustness of this process against structural heterogeneities remains unexplored, to the best of our knowledge. Here, we employ a combination of time-resolved photoemission electron microscopy (TR-PEEM) and atomic force microscopy to investigate the spatially resolved hot-electron-transfer dynamics at the monolayer (1L) MoS2/Au interface. A spatially heterogeneous distribution of 1L-MoS2/Au gap distances, along with the sub-80 nm spatial-and sub-60 fs temporal resolution of TR-PEEM, permits the simultaneous measurement of electron-transfer rates across a range of 1L-MoS2/Au distances. These decay exponentially as a function of distance, with an attenuation coefficient β ∼0.06 ± 0.01 Å-1, comparable to molecular wires. Ab initio simulations suggest that surface plasmon-like states mediate hot-electron-transfer, hence accounting for its weak distance dependence. The weak distance dependence of the interfacial hot-electron-transfer rate indicates that this process is insensitive to distance fluctuations at the TMD/metal interface, thus motivating further exploration of optoelectronic devices based on hot carriers.

Original languageEnglish (US)
Pages (from-to)819-828
Number of pages10
JournalACS nano
Volume15
Issue number1
DOIs
StatePublished - Jan 26 2021
Externally publishedYes

Keywords

  • TMD/metal interface
  • hot carriers
  • time-resolved photoemission electron microscopy
  • transition-metal dichalcogenides
  • ultrafast spectroscopy

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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