Delocalized Hot Electron Generation with Propagative Surface Plasmon Polaritons

Abstract

Hot electrons generated within plasmonic structures possess a high kinetic energy that can be employed to drive and catalyze a huge range of physicochemical processes at the metallic interface. Up to now, these photogenerated hot carriers were mainly generated within simple plasmonic nanoparticles where hot carrier localization coincides spatially with the position optical excitation. A current challenge for the development of future plasmonic-based hot electron devices requires the ability for a delocalized hot carrier production to control on a large-distance their spatial distribution. Here, we demonstrate the remote generation of hot electrons by launching a propagative surface plasmon on a gold waveguide. Such hot carriers can be produced at distances of several microns from the excitation. Moreover, using far- and near-field hyperspectral microscopy, we show that hot carriers present spatial and energy distributions driven by the propagating plasmon field distribution itself. This opens the door to the engineering of complex hot carrier devices through the management of the plasmon propagation for next level hot-electron-based applications.

Coherent Interference Fringes of Two-Photon Photoluminescence in Individual Au Nanoparticles: The Critical Role of the Intermediate State

“…According to the reconstructed plasmon-enhanced electric field E(t) from these measurements, the pulse duration and thus the dephasing time can be derived. On the other aspect, the hot-carrier relaxation dynamics on the time scales of picoseconds have been studied by multiphoton photoluminescence (MPPL) [28][29][30] . The temporal response of the carriers' relaxation extending from sub-to several picoseconds has been reported.…”

Polarization-Dependent Light Emission and Charge Creation in MoS2 Monolayers on Plasmonic Au Nanogratings

“…Plasmonic metal nanostructures allow us to strongly enhance light absorption and emission in extremely thin transition metal dichalcogenide (TMD) layers. − Thus, intensive research effort has focused on exploring the novel physical phenomena in TMD/metal hybrid nanostructures. Both localized surface plasmon (LSP) and surface plasmon polariton (SPP) effects can strongly confine light near metal nanostructures, but they have some distinct physical features.…”

“…For example, LSP resonance appears when an incoming photon has a suitable energy. − , In contrast, SPP excitation occurs when an incoming photon has appropriate energy, polarization, and incident angle . With the help of the propagating SPP, TMD/metal nanostructures can exhibit selective excitation of SPP modes, amplification of a specific exciton, strong exciton–plasmon coupling, ultrafast hot electron transfer, or delocalized hot carrier production. − These intriguing physical phenomena have potential for various applications, such as photodetectors, light-emitting devices, polariton lasers, optoelectronic circuit elements, and photocatalysts. − …”

“…When TMD materials are integrated with a periodic array of metal nanostructures, SPP–exciton coupling as well as LSP–exciton coupling can occur. − Excitons in TMDs have relatively large binding energies, allowing the rich physics of plasmonic phenomena to be studied at room temperature. Optical techniques have been used to unveil the plasmon-mediated intriguing phenomena. − However, they cannot directly reveal the behaviors of charge carriers involved in interactions with plasmons and photons. Kelvin probe force microscopy (KPFM) measures the contact potential difference ( V CPD ) with a spatial resolution of a few tens of nanometers. ,, KPFM has been used to investigate the light-induced V CPD modification in TMD/metal nanostructures. , However, there has been few explicit research work to study the SPP–exciton coupling in TMD/metal hybrid systems. − , It will be interesting to attempt direct visualization of the interaction of SPPs, photons, and charge carriers using KPFM.…”

A Multibeam Interference Model for Analyzing Complex Near‐Field Images of Polaritons in 2D van der Waals Microstructures

“…For example, high‐quality graphene encapsulated between two h‐BN films possesses plasmons that exhibit unprecedentedly low damping combined with strong field confinement, HPs in h‐BN can be controlled by crystal thickness, HPs in MoO 3 crystals display in‐plane anisotropy with high confinement and low loss, and the propagating direction of HPs can be controlled by metasurfaces . Numerous studies have demonstrated applications of s‐SNOM nanoimaged vdW polaritons, including hot electron detection, surface‐enhanced infrared (IR) absorption, ultrafast plasmonic switching, observation of slow light, metasurface engineering, hyperfocusing lens, and probing optical constants …”