An official website of the United States government
Oxide-metal-based hybrid materials have gained great research interest in recent years owing to their potential for multifunctionality, property coupling, and tunability. Specifically, oxide-metal hybrid materials in a vertically aligned nanocomposite (VAN) form could produce pronounced anisotropic physical properties, e.g. , hyperbolic optical properties. Herein, self-assembled HfO 2 -Au nanocomposites with ultra-fine vertically aligned Au nanopillars (as fine as 3 nm in diameter) embedded in a HfO 2 matrix were fabricated using a one-step self-assembly process. The film crystallinity and pillar uniformity can be obviously improved by adding an ultra-thin TiN-Au buffer layer during the growth. The HfO 2 -Au hybrid VAN films show an obvious plasmonic resonance at 480 nm, which is much lower than the typical plasmonic resonance wavelength of Au nanostructures, and is attributed to the well-aligned ultra-fine Au nanopillars. Coupled with the broad hyperbolic dispersion ranging from 1050 nm to 1800 nm in wavelength, and unique dielectric HfO 2 , this nanoscale hybrid plasmonic metamaterial presents strong potential for the design of future integrated optical and electronic switching devices.
more »
« less
Electroluminescence as a Probe of Strong Exciton–Plasmon Coupling in Few-Layer WSe 2
The manipulation of coupled quantum excitations is of fundamental importance in realizing novel photonic and optoelectronic devices. We use electroluminescence to probe plasmon–exciton coupling in hybrid structures consisting of a nanoscale plasmonic tunnel junction and few-layer two-dimensional transition-metal dichalcogenide transferred onto the junction. The resulting hybrid states act as a novel dielectric environment that affects the radiative recombination of hot carriers in the plasmonic nanostructure. We determine the plexcitonic spectrum from the electroluminescence and find Rabi splittings exceeding 50 meV in the strong coupling regime. Our experimental findings are supported by electromagnetic simulations that enable us to explore systematically and in detail the emergence of plexciton polaritons as well as the polarization characteristics of their far-field emission. Electroluminescence modulated by plexciton coupling provides potential applications for engineering compact photonic devices with tunable optical and electrical properties.
more »
« less
- Award ID(s):
- 2309941
- PAR ID:
- 10511670
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- Nano Letters
- Volume:
- 24
- Issue:
- 1
- ISSN:
- 1530-6984
- Page Range / eLocation ID:
- 525 to 532
- Subject(s) / Keyword(s):
- plasmonics, nanoscale junction, hot-carrier dynamics, plexciton, strong coupling
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Graphene can support surface plasmons with higher confinement, lower propagation loss, and substantially more tunable response compared to usual metal-based plasmonic structures. Interestingly, plasmons in graphene can strongly couple with nanostructures and gratings placed in its vicinity to form new hybrid systems that can provide a platform to investigate more complicated plasmonic phenomena. In this Perspective, an analysis on the excitation of highly confined graphene plasmons and their strong coupling with metallic or dielectric gratings is performed. We emphasize the flexibility in the efficient control of light–matter interaction by these new hybrid systems, benefiting from the interplay between graphene plasmons and other external resonant modes. The hybrid graphene-plasmon grating systems offer unique tunable plasmonic resonances with enhanced field distributions. They exhibit a novel route to realize practical emerging applications, including nonreciprocal devices, plasmonic switches, perfect absorbers, nonlinear structures, photodetectors, and optical sensors.more » « less
-
Abstract The cooperative phenomena stemming from the radiation field-mediated coupling between individual quantum emitters are presently attracting broad interest for applications related to on-chip photonic quantum memories and long-range entanglement. Common to these applications is the generation of electro-magnetic modes over macroscopic distances. Much research, however, is still needed before such systems can be deployed in the form of practical devices, starting with the investigation of alternate physical platforms. Quantum emitters in two-dimensional (2D) systems provide an intriguing route because these materials can be adapted to arbitrarily shaped substrates to form hybrid systems wherein emitters are near-field-coupled to suitable optical modes. Here, we report a scalable coupling method allowing color center ensembles in a van der Waals material (hexagonal boron nitride) to couple to a delocalized high-quality plasmonic surface lattice resonance. This type of architecture is promising for photonic applications, especially given the ability of the hexagonal boron nitride emitters to operate as single-photon sources at room temperature.more » « less
-
We have investigated spin related processes in fullerene C 60 devices using several experimental techniques, which include magnetic field effect of photocurrent and electroluminescence in C 60 -based diodes; spin polarized carrier injection in C 60 -based spin-valves; and pure spin current generation in NiFe/C 60 /Pt trilayer devices. We found that the ‘curvature-related spin orbit coupling’ in C 60 plays a dominant role in the obtained spin-related phenomena. The measured magneto-photocurrent and magneto-electroluminescence responses in C 60 diodes are dominated by the difference in the g -values of hole and electron polarons in the fullerene molecules. We also obtained giant magneto-resistance of ∼10% at 10 K in C 60 spin-valve devices, where spin polarized holes are injected into the C 60 interlayer. In addition, using the technique of spin-pumping in NiFe/C 60 /Pt trilayer devices with various C 60 interlayer thicknesses we determined the spin diffusion length in C 60 films to be 13 ± 2 nm at room temperature.more » « less
-
Abstract Tunable Fano resonances and plasmon–exciton coupling are demonstrated at room temperature in hybrid systems consisting of single plasmonic nanoparticles deposited on top of the transition metal dichalcogenide monolayers. By using single Au nanotriangles (AuNTs) on monolayer WS2as model systems, Fano resonances are observed from the interference between a discrete exciton band of monolayer WS2and a broadband plasmonic mode of single AuNTs. The Fano lineshape depends on the exciton binding energy and the localized surface plasmon resonance strength, which can be tuned by the dielectric constant of surrounding solvents and AuNT size, respectively. Moreover, a transition from weak to strong plasmon–exciton coupling with Rabi splitting energies of 100–340 meV is observed by rationally changing the surrounding solvents. With their tunable plasmon–exciton interactions, the proposed WS2–AuNT hybrids can open new pathways to develop active nanophotonic devices.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.nanolett.3c04684
