Electronic Structure of the Plasmons in Metal Nanocrystals: Fundamental Limitations for the Energy Efficiency of Hot Electron Generation

Chang, Le; Besteiro, Lucas V.; Sun, Jiachen; Santiago, Eva Yazmin; Gray, Stephen K.; Wang, Zhiming; Govorov, Alexander O.

doi:10.1021/acsenergylett.9b01617

Cited by 125 publications

(157 citation statements)

References 74 publications

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“…The scattering of electrons by surface or in the highly confined electromagnetic fields in hot spot enables the nonconservation of the linear momentum of electrons. The electrons can absorb the full energy of the photon to generate the high-energy hot carriers 38 , 39 . Therefore, the electrons that reside below the Fermi level are excited to a higher, unoccupied energy level, generating hot electrons (between E f and E f +1.96 eV) and leaving holes with energies between E f −1.96 eV and E f (Fig.…”

Section: Resultsmentioning

confidence: 99%

Probing nanoscale spatial distribution of plasmonically excited hot carriers

et al. 2020

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Surface plasmons (SPs) of metals enable the tight focusing and strong absorption of light to realize an efficient utilization of photons at nanoscale. In particular, the SP-generated hot carriers have emerged as a promising way to efficiently drive photochemical and photoelectric processes under moderate conditions. In situ measuring of the transport process and spatial distribution of hot carriers in real space is crucial to efficiently capture the hot carriers. Here, we use electrochemical tip-enhanced Raman spectroscopy (EC-TERS) to in situ monitor an SP-driven decarboxylation and resolve the spatial distribution of hot carriers with a nanometer spatial resolution. The transport distance of about 20 nm for the reactive hot carriers is obtained from the TERS imaging result. The hot carriers with a higher energy have a shorter transport distance. These conclusions can be guides for the design and arrangement of reactants and devices to efficiently make use of plasmonic hot carriers.

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Section: Resultsmentioning

confidence: 99%

Probing nanoscale spatial distribution of plasmonically excited hot carriers

et al. 2020

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“…To date, however, only a few hot-holedriven photodetectors have been reported. [17][18][19][20][21][22] These devices primarily employ semiconductors with relatively small bandgaps (e.g. Si), limiting their operation to the near-infrared regime where photoexcitation of hot holes originates from the sp-band of the metal.…”

Section: Figure 1: Optical Generation and Collection Of Hot Holes In mentioning

confidence: 99%

Hot-Hole versus Hot-Electron Transport at Cu/GaN Heterojunction Interfaces

et al. 2020

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Among all plasmonic metals, copper (Cu) has the greatest potential for realizing optoelectronic and photochemical hot-carrier devices, thanks to its CMOS compatibility and outstanding catalytic properties. Yet, relative to gold (Au) or silver (Ag), Cu has rarely been studied and the fundamental properties of its photoexcited hot carriers are not well understood. Here, we demonstrate that Cu nanoantennas on p-type gallium nitride (p-GaN) enables hot-hole-driven photodetection across the visible spectrum. Importantly, we combine experimental measurements of the internal quantum efficiency (IQE) with ab initio theoretical modelling to clarify the competing roles of hot-carrier energy and mean-free path on the performance of hot-hole devices above and below the interband threshold of the metal. We also examine Cu-based plasmonic photodetectors on corresponding n-type GaN substrates that operate via the collection of hot electrons. By comparing hot hole and hot-electron photodetectors that employ the same metal/semiconductor interface (Cu/GaN), we further elucidate the relative advantages and limitations of these complementary plasmonic systems. In particular, we find that harnessing hot holes with p-type semiconductors is a promising strategy for plasmon-driven photodetection across the visible and ultraviolet regimes. Given the technological relevance of Cu and the fundamental insights provided by our combined experimental and theoretical approach, we anticipate that our studies will have a broad impact on the design of hot-carrier optoelectronic devices and plasmon-driven photocatalytic systems.

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“…The efficiency of the photosensor is largely determined by the absorption intensity of radiation by its cathode. It is desirable to maximize this intensity and, consequently, the number of photoexcited (hot) electrons [21][22][23][24]. The local intensity value of radiation absorption is determined by the following equation [24]:…”

Section: Spectral and Spatial Dependences Of Amplification Of The Optmentioning

confidence: 99%

A Visible and Near-IR Tunnel Photosensor with a Nanoscale Metal Emitter: The Effect of Matching of Hot Electrons Localization Zones and a Strong Electrostatic Field

et al. 2019

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The results of the research and design of a novel vacuum photosensor with a planar molybdenum blade structure are presented. The advanced prototype implements the principle of an increasing penetrability of the Schottky barrier for the metal–vacuum interfaces under the action of an external strong electrostatic field. Theoretical and experimental substantiation of the photosensor performance in a wide range of wavelengths (from 430 to 680 nm and from 800 to 1064 nm) beyond the threshold of the classical photoelectric effect is given. The finite element method was applied to calculate distribution of the optical and electrostatic fields inside the photosensor structure. The sensor current-to-light response was studied using the periodic pulsed irradiation with the tunable wavelength. It was shown that the nanoscale localization zones of two types are formed near the surface of the blade tip: the zone of an increased concentration of hot electrons localized inside the molybdenum blade, and the zone with an increased strength of the external electrostatic field localized outside the blade. In general, the mutual positions of these zones may not coincide, whereas the position of the first-type localization zone significantly varies with the changes in the wavelength of the irradiating light. This causes features in the spectrum of the quantum yield of the photosensor such as expressed non-monotonic behavior and occurrence of sharp dips. The design of the photosensor that provides matching of the positions for both types of localization zones was proposed; the manufactured prototypes of the designed device were experimentally studied. In the designed photosensor, the ballistic transport of photoelectrons in the vacuum gap with a strong field provides a possibility for the creation of ultra-fast optoelectronic devices, such as modulators, detectors, and generators.

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Electronic Structure of the Plasmons in Metal Nanocrystals: Fundamental Limitations for the Energy Efficiency of Hot Electron Generation

Cited by 125 publications

References 74 publications

Probing nanoscale spatial distribution of plasmonically excited hot carriers

Probing nanoscale spatial distribution of plasmonically excited hot carriers

Hot-Hole versus Hot-Electron Transport at Cu/GaN Heterojunction Interfaces

A Visible and Near-IR Tunnel Photosensor with a Nanoscale Metal Emitter: The Effect of Matching of Hot Electrons Localization Zones and a Strong Electrostatic Field

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