Multiexponential photoluminescence decay of blinking nanocrystal ensembles

Dunn, Kerry; Derr, Julien; Johnston, T. W.; Chaker, Mohamed; Rosei, Federico

doi:10.1103/physrevb.80.035330

Cited by 25 publications

(26 citation statements)

References 77 publications

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“…Previous [2,12,36,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] and our own [21] studies have shown that the integral PL time decay in Si-based nanostructures can be fitted by the well-known stretched exponential function…”

Section: Optical Propertiesmentioning

confidence: 99%

From amorphous to crystalline silicon nanoclusters: structural effects on exciton properties

Borrero-González

Nunes

Guimarães

et al. 2011

J. Phys.: Condens. Matter

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Synchrotron x-ray absorption spectroscopy (XAS) and electron spin resonance (ESR) experiments were performed to determine, in combination with Raman spectroscopy and x-ray diffraction (XRD) data from previous reports, the structure and paramagnetic defect status of Si-nanoclusters (ncls) at various intermediate formation stages in Si-rich Si oxide films having different Si concentrations (y = 0.36-0.42 in Si y O 1−y ), fabricated by electron cyclotron resonance plasma-enhanced chemical vapor deposition and isochronally (2 h) annealed at various temperatures (T a = 900-1100 • C) under either Ar or (Ar + 5%H 2 ) atmospheres. The corresponding emission properties were studied by stationary and time dependent photoluminescence (PL) spectroscopy in correlation with the structural and defect properties. To explain the experimental data, we propose crystallization by nucleation within already existing amorphous Si-ncls as the mechanism for the formation of the Si nanocrystals in the oxide matrix. The cluster-size dependent partial crystallization of Si-ncls at intermediate T a can be qualitatively understood in terms of a 'crystalline core-amorphous shell' Si-ncl model. The amorphous shell, which is invisible in most diffraction and electron microscopy experiments, is found to have an important impact on light emission. As the crystalline core grows at the expense of a thinning amorphous shell with increasing T a , the PL undergoes a transition from a regime dominated by disorder-induced effects to a situation where quantum confinement of excitons prevails.

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Section: Optical Propertiesmentioning

confidence: 99%

From amorphous to crystalline silicon nanoclusters: structural effects on exciton properties

Borrero-González

Nunes

Guimarães

et al. 2011

J. Phys.: Condens. Matter

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“…21 Recently, the non-exponential PL dynamics of ensembles of localized centers have been linked to the PL intermittency, also called blinking, of individual centers whose emission is observed under continuous excitation conditions. 23,24 Blinking is observed in a variety of systems such as colloidal and self-assembled quantum dots (QDs) 23,[25][26][27] and Si nanocristals, 24 and is attributed to the formation of metastable, charge-separated (CS) dark states.…”

Section: Introductionmentioning

confidence: 99%

Carrier recombination dynamics inInxGa1−xN/GaNmultiple quantum wells

et al. 2010

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We have mesured the carrier recombination dynamics in InGaN/GaN multiple quantum wells over an unprecedented range in intensity and time by means of time-resolved photoluminescence spectroscopy. We find that, at times shorter than 30 ns, they follow an exponential form, and a power law at times longer than 1 µs. To explain these biphasic dynamics, we propose a simple three-level model where a charge-separated state interplays with the radiative state through charge transfer following a tunneling mechanism. We show how the distribution of distances in chargeseparated states controls the dynamics at long time. Our results imply that charge recombination happens on nearly-isolated clusters of localization centers.

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“…In some papers, β is shown being almost independent on emission energy in both PSi‐ and SiO 2 ‐embedded Si NCs . Other studies found β decreasing above and below 1.4 eV or above and below 1.7 eV in different forms of Si NCs. These observations suggest an optimum size of NCs emitting either near 1.4 or 1.7 eV with the narrowest distribution of decay constants (Section ).…”

Section: Resultsmentioning

confidence: 96%

“…Alternatively, single fluorophores of almost all light sources are well known for the phenomenon of intensity intermittence (“blinking”). Dunn et al suggested that PL relaxation is affected by blinking mechanism that produces sudden changes in PL intensity during continuous excitation which can lead to the SE shape of decay curve. 3) Direct consequence of indirect bandgap of Si is a broad homogeneous line at room temperature.…”

Section: Resultsmentioning

confidence: 99%

Spectral Dependencies of the Stretched Exponential Dispersion Factor and Photoluminescence Quantum Yield as a Common Feature of Nanocrystalline Si

Greben

Khoroshyy

Valenta

2019

Physica Status Solidi (a)

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Herein, the spectral dependencies of the dispersion factor β (from the stretched exponential function) and photoluminescence (PL) quantum yield (QY) of silicon nanocrystals (Si NCs) are thoroughly studied. Spectrally resolved PL decay kinetics of Si NCs in both liquid and solid samples are measured and their corresponding distributions of rates are retrieved by means of the hybrid maximum‐entropy method. This enables us to demonstrate a direct correlation of dispersion factor β with the width of rate distribution. Here, the evidence of the same step‐like spectral dependence of rate distribution widths (dispersion factor) for different forms of nanocrystalline silicon (including porous silicon and chemically synthesized Si NCs) is presented suggesting intrinsic (core‐related) origin of rate distributions. Spectral dependence of normalized QY of Si NCs reveals two characteristic peaks with spectral positions at ≈1.42 and ≈1.68 eV. A similar peak in QY spectral dependence of CdSe quantum dots (QDs) is found, which suggests its common origin regardless the material of semiconductor QDs.

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Multiexponential photoluminescence decay of blinking nanocrystal ensembles

Cited by 25 publications

References 77 publications

From amorphous to crystalline silicon nanoclusters: structural effects on exciton properties

From amorphous to crystalline silicon nanoclusters: structural effects on exciton properties

Carrier recombination dynamics inInxGa1−xN/GaNmultiple quantum wells

Spectral Dependencies of the Stretched Exponential Dispersion Factor and Photoluminescence Quantum Yield as a Common Feature of Nanocrystalline Si

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