Evidence of Plasmon Enhanced Charge Transfer in Large‐Area Hybrid Au–MoS₂ Metasurface

Abstract

Hybrid plasmonic‐semiconductor assemblies are receiving considerable attention due to the possibility to achieve hot‐carrier‐based photodetection. In this context, 2D transition metal dichalcogenides (TMDs) coupled to metal nanostructures are very promising. However, the plasmon‐to‐TMD carrier injection process is extremely challenging to achieve and even to reveal in a clear‐cut way. Herein, a report of multiple transient absorption ultrafast measurements, with tunable pump excitation, enabling quantitative comparison between the ultrafast behavior of metal nanostructures, TMDs, and their assembly is shown. This allows to provide the evidence of plasmon‐enhanced charge injection from Au nanostripes to a rippled‐shaped molybdenum disulfide (MoS2) few‐layer nanosheet. Finite element method numerical simulations and modeling of the transient optical response corroborate the charge transfer mechanism, showing that the experimental data cannot be described in terms of the thermomodulational nonlinearity of gold nanostripes or by simple superposition of metal and semiconductor responses. The sample is obtained by a self‐organization process on a large area; this demonstrates that plasmon‐enhanced photon harvesting exploiting hot‐electron injection can be achieved on a large area (approximately cm2) surface and provides a substantial advancement toward scalable ultrathin photodetection devices based on hot‐electrons technology.

Recent Progress in the Synthesis of MoS2 Thin Films for Sensing, Photovoltaic and Plasmonic Applications: A Review

“…Regarding the applications, apart from those described in this review, 2D-MoS 2 exhibits very appealing performances in infrared domains especially in combination with metamaterials such as passive radiative cooling. There are some emerging works [177][178][179][180] related to this aspect such as developing hybrid MoS 2 thin films with new structures, including metamaterials, metasurfaces, photonic crystals, plasmonics, etc. Similarly, the development of 2D material-based antennas remains unsatisfactory as most of the known achievements on MoS 2 in this domain are developed theoretically.…”

Plasmonic Effect on the Magneto-Optical Property of Monolayer WS2 Studied by Polarized-Raman Spectroscopy

“…For the hybrids composed of TMDs and noble metal NPs, the "hot carriers" are generated and transfer from NPs to WS 2 flake under the light illumination [40,41]. Employing ultrafast transient absorption spectroscopy with pumping photon energy below the indirect bandgap of the rippled MoS 2 quadrilayer, Camellini et al directly demonstrated a plasmon-induced charge transfer between Au and MoS 2 [42]. As reported by Bhattacharya and coauthors, the Au NPs acted as dopants to WS 2 in the plasmonic hybrid nanostructures [28].…”

Dual functionality of surface plasmon resonance and barrier layer on the photosensing and optical nonlinearity of ZnO nanorod arrays

“…(i) photonic enhancement, which requires surface patterning of the metal-semiconductor interface to concentrate the incident light, trap it and increase the photoconversion; 4 (ii) direct electron transfer (DET) of the high-energy (1-4 eV) hot electrons of noble metal NPs that are not in thermodynamic equilibrium into the CB of the adjacent semiconductor; 2,19,20 (iii) large photogenerated electron-hole dipoles in the plasmonic NPs induce electron-hole dipoles in the semiconductor, also known as plasmon-induced resonance energy transfer (PIRET). 2,12,21 Photonic enhancement is highly successful only when the incident photon's energy exceeds the bandgap energy of the semiconductor.…”