Radiative versus nonradiative decay processes in silicon nanocrystals probed by time-resolved photoluminescence spectroscopy

Dovrat, M.; Yuli, Goshen,; Jędrzejewski, J.; Balberg, I.; Sa’ar, A.

doi:10.1103/physrevb.69.155311

Cited by 164 publications

(167 citation statements)

References 44 publications

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“…Nanocluster lifetimes tend to be growth dependent and vary strongly with the degree of crystallinity of the clusters, their size, mean separation, the nature of the matrix surrounding them, and the presence of nonradiative deexcitation pathways. 23 For example, Cho et al demonstrated lifetimes between 2 and 60 s for 3.4 nm diameter clusters, 24 and implanted material can show lifetimes between Ͻ5 and 30 s. 25 In contrast, longer lifetimes have been reported in the region of 50-100 s, 26 and even as long as 500 s for noninteracting nanoclusters. 27 Clearly, an interpretation of the stretched exponential rise time data requires considerable care.…”

Section: Analysis and Refinement Of The Basic Modelmentioning

confidence: 99%

Generalized rate-equation analysis of excitation exchange between silicon nanoclusters and erbium ions

et al. 2008

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We discuss the use of rate equations to analyze the sensitization of erbium luminescence by silicon nanoclusters. In applying the general form of second-order coupled rate-equations to the Si nanocluster-erbium system, we find that the photoluminescence dynamics cannot be described using a simple rate equation model. Both rise and fall times exhibit a stretched exponential behavior, which we propose arises from a combination of a strongly distance-dependent nanocluster-erbium interaction, along with the finite size distribution and indirect band gap of the silicon nanoclusters. Furthermore, the low fraction of erbium ions that can be excited nonresonantly is a result of the small number of ions coupled to nanoclusters.

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Section: Analysis and Refinement Of The Basic Modelmentioning

confidence: 99%

Generalized rate-equation analysis of excitation exchange between silicon nanoclusters and erbium ions

et al. 2008

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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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“…As It is known that, in a low excitation regime, the PL intensity is generally given by the expression I PL~ (τ PL /τ R )σφN, where τ PL and τ R are the photoluminescence and radiative lifetimes, respectively, φ is the photon flux of the laser pump (constant throughout our experiment), N is the density of nanocrystals in the film, and σ is their excited cross-section [17]. The unchanged spectral shape of PL bands and similar position of PL maximum in samples with and without Ni interlayer mean that in the SiO x /Ni/Si structures after annealing no additional emitting centers are introduced to compare with the reference one.…”

Section: Resultsmentioning

confidence: 99%

Nickel-induced enhancement of photoluminescence in nc-Si-SiOx nanostructures

Michailovska¹

2014

Semicond. Phys. Quantum Electron. Optoelectron.

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Abstract. The effect of nickel silicide interlayer on the intensity of photoluminescence (PL) from Si nanoclusters (nc) in normally deposited and obliquely deposited in vacuum SiO x /Ni/Si structures have been studied using spectral and time-resolved PL measurements. It has been shown that the intensity of PL band in SiO x /Ni/Si samples is essentially higher than that in reference SiO x /Si samples (without the nickel interlayer) with the same characteristics and treatment. The PL intensity enhancement factor is equal to 5.77 for normally deposited samples and 18 for obliquely deposited samples. The unchanged spectral shape of PL bands and similar position of PL maximum in samples with and without nickel silicide interlayer indicates that in the SiO x /Ni/Si structures after annealing no additional emitting centers are introduced to compare with reference one. Time-resolved measurements showed that PL decay rate was decreased from 8. for SiO x /Si specimens to 2.8610 4 s -1 for SiO x /Ni/Si one. The emission decay rate distribution was determined by fitting the experimental decay curves to the stretchedexponential model. The observed narrow decay rate distribution, decrease of the PL decay rate and enhancement of the PL intensity in SiO x /Ni/Si samples can be assigned to the processes of nickel silicide passivation of the dangling bonds at the interface of Si nanoparticles and the silicon oxide matrix, which is more effective in porous samples.

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Radiative versus nonradiative decay processes in silicon nanocrystals probed by time-resolved photoluminescence spectroscopy

Cited by 164 publications

References 44 publications

Generalized rate-equation analysis of excitation exchange between silicon nanoclusters and erbium ions

Generalized rate-equation analysis of excitation exchange between silicon nanoclusters and erbium ions

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

Nickel-induced enhancement of photoluminescence in nc-Si-SiOx nanostructures

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