Chemosensors (Mar 2022)

Optical Response of CVD-Grown ML-WS<sub>2</sub> Flakes on an Ultra-Dense Au NP Plasmonic Array

  • Marzia Ferrera,
  • Lorenzo Ramò,
  • Domenica Convertino,
  • Giorgio Orlandini,
  • Simona Pace,
  • Ilya Milekhin,
  • Michele Magnozzi,
  • Mahfujur Rahaman,
  • Dietrich R. T. Zahn,
  • Camilla Coletti,
  • Maurizio Canepa,
  • Francesco Bisio

Journal volume & issue
Vol. 10, no. 3
p. 120


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The combination of metallic nanostructures with two-dimensional transition metal dichalcogenides is an efficient way to make the optical properties of the latter more appealing for opto-electronic applications. In this work, we investigate the optical properties of monolayer WS2 flakes grown by chemical vapour deposition and transferred onto a densely-packed array of plasmonic Au nanoparticles (NPs). The optical response was measured as a function of the thickness of a dielectric spacer intercalated between the two materials and of the system temperature, in the 75–350 K range. We show that a weak interaction is established between WS2 and Au NPs, leading to temperature- and spacer-thickness-dependent coupling between the localized surface plasmon resonance of Au NPs and the WS2 exciton. We suggest that the closely-packed morphology of the plasmonic array promotes a high confinement of the electromagnetic field in regions inaccessible by the WS2 deposited on top. This allows the achievement of direct contact between WS2 and Au while preserving a strong connotation of the properties of the two materials also in the hybrid system.