Ultrafast Carrier and Lattice Dynamics in Plasmonic Nanocrystalline Copper Sulfide Films

Anton Yu, Amaresh Shukla, Mark van Schilfgaarde, Mark Green, Anatoly Zayats

Research output: Contribution to journalArticlepeer-review

12 Scopus Citations

Abstract

Excited carrier dynamics in plasmonic nanostructures determines many important optical properties such as nonlinear optical response and photocatalytic activity. Here it is shown that mesoscopic plasmonic covellite nanocrystals with low free-carrier concentration exhibit a much faster carrier relaxation than in traditional plasmonic materials. A nonequilibrium hot-carrier population thermalizes within first 20 fs after photoexcitation. A decreased thermalization time in nanocrystals compared to a bulk covellite is consistent with the reduced Coulomb screening in ultrathin films. The subsequent relaxation of thermalized, equilibrium electron gas is faster than in traditional plasmonic metals due to the lower carrier concentration and agrees well with that in a bulk covellite showing no evidence of quantum confinement or hot-hole trapping at the surface states. The excitation of coherent optical phonon modes in a covellite is also demonstrated, revealing coherent lattice dynamics in plasmonic materials, which until now was mainly limited to dielectrics, semiconductors, and semimetals. These findings show advantages of this new mesoscopic plasmonic material for active control of optical processes.

Original languageAmerican English
Article number2000346
Number of pages9
JournalLaser and Photonics Reviews
Volume15
Issue number3
DOIs
StatePublished - 2021

Bibliographical note

Publisher Copyright:
© 2021 The Authors. Laser & Photonics Reviews published by Wiley-VCH GmbH

NREL Publication Number

  • NREL/JA-5F00-79211

Keywords

  • coherent optical phonons
  • copper sulfide
  • nonequilibirium processes
  • plasmonics
  • ultrafast hot-carrier dynamics

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