Controlling quantum-dot light absorption and emission by a surface-plasmon field

Huang, Danhong; Easter, Michelle; Gumbs, Godfrey; Maradudin, A. A.; Lin, Shawn‐Yu; Cardimona, D. A.; Zhang, Xiang

doi:10.1364/oe.22.027576

Cited by 17 publications

(17 citation statements)

References 37 publications

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“…The carrier diffusion and capture processes have been theoretically investigated by describing the temporal evolution of the electron-hole occupation number ( N ) of the QD excited states using a dynamical equation and including the plasmon near-field effect on the absorption and emission property of the QDs 25, 27 . For the first excited state of a QD, the temporal evolution of the occupation number ( N 1 ) is described aswhere α represents electrons or holes, Ω is the angular frequency of the incident photons, I 0 (Ω, d ) is the electric field intensity experienced by the QD at thickness d , (where h is Planck’s constant), β is the absorption coefficient of the QD, is the rate of spontaneous emission, γ and κ are the rate of capturing carriers from the bulk GaAs and the InGaAs well by the QD, respectively, and m = 1, 2, …, M are quantum numbers of all the bound energy states.…”

Section: Resultsmentioning

confidence: 99%

Active Mediation of Plasmon Enhanced Localized Exciton Generation, Carrier Diffusion and Enhanced Photon Emission

Haq

Addamane

Kafle

et al. 2017

Sci Rep

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Understanding the enhancement of charge carrier generation and their diffusion is imperative for improving the efficiency of optoelectronic devices particularly infrared photodetectors that are less developed than their visible counterpart. Here, using gold nanorods as model plasmonic systems, InAs quantum dots (QDs) embedded in an InGaAs quantum well as an emitter, and GaAs as an active mediator of surface plasmons for enhancing carrier generation and photon emission, the distance dependence of energy transfer and carrier diffusion have been investigated both experimentally and theoretically. Analysis of the QD emission enhancement as a function of distance reveals a Förster radius of 3.85 ± 0.15 nm, a near-field decay length of 4.8 ± 0.1 nm and an effective carrier diffusion length of 64.0 ± 3.0 nm. Theoretical study of the temporal-evolution of the electron-hole occupation number of the excited states of the QDs indicates that the emission enhancement trend is determined by the carrier diffusion and capture rates.Excitons and localized surface plasmons are the two fundamental excitation characteristics of nanoscale materials. The coupling between excitonic and plasmonic materials promises control of photon emission 1-3 and creation of new metamaterial properties 4, 5 that do not exist in nature. Fundamental understanding of exciton-plasmon interaction can lead to development of efficient photovoltaics [6][7][8] , photodetectors 9,10 , photocatalysis 11,12 and other optoelectronic devices. Classic experiments on exciton-plasmon interactions have often used optically transparent spacer materials between the plasmonic metal and excitonic semiconductor materials 1,3,13,14 . Coupling through optically transparent spacers does not allow studying charge transport process. On the other hand, studies on plasmon enhanced near-infrared photo-detectors are focused on coupling metallic two-dimensional-hole-arrays with layered semiconductor materials such as InAs/InGaAs/GaAs dot-in-a-well (DWELL) structures 9,15 . This enhancement mechanism exploits the extraordinary optical transmission effect 16 , where the transmitted field extends to about 1 μm length covering the whole active region 15 , and does not allow fundamental understanding of localized exciton generation, charge carrier diffusion and recombination.In this work, energy transfer and charge carrier diffusion are investigated systematically taking advantage of the tight electric field localization at the interfaces of plasmonic gold nanorods (AuNRs) and semiconductor GaAs that is grown over the InAs/InGaAs DWELL with accurate control of the GaAs thickness. When excitation energy that is above the GaAs band gap is chosen, the localized electric field enhances generation of electron-hole pairs (excitons) in a defined spatial region away from the InAs QDs so that carrier diffusion and capture rates are studied by monitoring the emission intensity of the QDs. The fact that the GaAs thickness can be controlled with sub-nanometer accuracy allows us to study the distanc...

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Section: Resultsmentioning

confidence: 99%

Active Mediation of Plasmon Enhanced Localized Exciton Generation, Carrier Diffusion and Enhanced Photon Emission

Haq

Addamane

Kafle

et al. 2017

Sci Rep

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“…The localization characteristics of such a retarded interaction ensure high sensitivity to dielectric environments surrounding graphene, including variations in the conducting substrate, cladding layer, electronic properties of embedded graphene, as well as the graphene distance from the conductor surface. This provides a unique advantage in wavelength-sensitive optical investigation of chemically-active molecules or proteins bound to carbon atoms in graphene [5,6].…”

Section: Discussionmentioning

confidence: 99%

“…Using the Green's function approach, [5] we convert Maxwell's equation for the electric field E(r, ω) into an integral equation in the spatial (r) domain, including a nonlocal source term to scatter the incident SPPF E inc (r, ω), where ω is the light frequency. After Fourier transforming this integral equation with respect to r , we obtain (µ, ν = 1, 2, 3)…”

Section: Theory and Methodsmentioning

confidence: 99%

“…However, the remaining question is, whether excited electrons or the holes exert an action back on the incident light? The answer to this lies in the induced optical-polarization field as a collection of local dipole moments from many displaced electrons and holes [3,4], which plays a role in scattering the electric-field component of the incident light [5,6]. Therefore, the quantum nature of Dirac electrons [7][8][9][10][11] is expected to be retained in the effects of optical polarization on the incident light with a complex distribution of the Landau-damping regions in comparison with that for two-dimensional electron gases in a quantum well [12].…”

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Effects of optical polarization on hybridization of radiative and evanescent field modes

et al. 2017

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Effects of induced optical polarization by Dirac electrons in graphene on the hybridization of radiative and evanescent fields is found. Such effects result in a localized polarization field which significantly modifies an incident surface-plasmon-polariton (SPP) field. This yields a high sensitivity to local dielectric environments and provides an investigative tool for molecules or proteins selectively bound with carbons. A scattering matrix is utilized with varied frequencies in the vicinity of the surface-plasmon (SP) resonance for the increase, decrease and even a full suppression of the polarization field, which enables accurate effective-medium theories to be constructed for Maxwellequation finite-difference time-domain methods. Moreover, double peaks in the absorption spectra for hybrid SP and graphene-plasmon modes are significant only with a large conductor plasma frequency, but are overshadowed by a round SPP peak at a small plasma frequency as the graphene is placed close to conductor surface. These resonant absorptions facilitate the polariton-only excitations, leading to polariton condensation for a threshold-free laser.

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“…Generally, EPFA may occur when the metal and QDs are in close vicinity to each other and when the metal emission spectrum suitably overlaps to the QDs absorptions [4]. The QDs-based EPFA has the particular applications including solar energy conversion and optical devices [5][6][7][8][9][10]. The EPFA has been applied to optoelectronic devices such as lasers, [11] light emitters [12], photodetectors, [13] biosensors [14], and solar cells [15,16].…”

Section: Introductionmentioning

confidence: 99%

Effects of morphology, diameter and periodic distance of the Ag nanoparticle periodic arrays on the enhancement of the plasmonic field absorption in the CdSe quantum dots

Kohnehpoushi

Eskandari

Ahmadi

et al. 2016

Photonics and Nanostructures - Fundamentals and Applications

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Controlling quantum-dot light absorption and emission by a surface-plasmon field

Cited by 17 publications

References 37 publications

Active Mediation of Plasmon Enhanced Localized Exciton Generation, Carrier Diffusion and Enhanced Photon Emission

Active Mediation of Plasmon Enhanced Localized Exciton Generation, Carrier Diffusion and Enhanced Photon Emission

Effects of optical polarization on hybridization of radiative and evanescent field modes

Effects of morphology, diameter and periodic distance of the Ag nanoparticle periodic arrays on the enhancement of the plasmonic field absorption in the CdSe quantum dots

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