Size-dependent photoluminescence from surface-oxidized Si nanocrystals in a weak confinement regime

Takeoka, Shinji; Fujii, Minoru; Hayashi, Shinji

doi:10.1103/physrevb.62.16820

Cited by 328 publications

(281 citation statements)

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“…As we can see, the differences between A (0) and A 2 (0) are rather significant. Note that the values A2(0) for different sizes of the quantum dot are in good agreement with the experimental data [9,10,11] and with the theoretical calculations of other authors who used another methods (such as local density approximation [12], tight-binding model [13,14] or pseudopotential method [15,16]). …”

Section: Hjv Fv (F)= Efp() Hisupporting

confidence: 85%

The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO₂:nc-Si

et al. 2001

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The results of an experimental research of the dependence of photoluminescence (PL) intensity in region about 800 nm for silicon nanoinclusions (quantum dots) obtained by Si ion implantation in Si0 2 on the dose of Si ions at two temperatures of an annealing Tan = 1000 and 11000 C are presented. It is established that in both cases the dependences have the shape of the curves with a maximum. For 11000 C the maximum is shifted to the lower dose. The influence of an additional ion doping by the phosphorus on intensity of PL is investigated depending on the dose (concentration) of P and the dose of the silicon at T., = 10000 C. It is shown, that in all the investigated region of P doses, the presence of P enhances the PL. The degree of the enhancement increases with the P dose, but the rate of the intensity enhancement goes down. With the growth of Si dose at the constant dose of P, the degree of the enhancement decreases. In an approximation of an effective mass, the energy spectra of a quantum dot are calculated at the presence of one or several P atoms for various their arrangement.

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Section: Hjv Fv (F)= Efp() Hisupporting

confidence: 85%

The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO₂:nc-Si

et al. 2001

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“…3, the effective recombination rates measured for samples A, B, and C are presented as a function of the emission wavelength. For completeness, the relation between the emission wavelength and Si NC diameter obtained by Takeoka et al 19 is given in the inset. We conclude that larger NCs exhibit lower effective recombination rates.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic investigations of dark Si nanocrystals in SiO2 and their role in external quantum efficiency quenching

Limpens

Gregorkiewicz

2013

Journal of Applied Physics

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The percentage of dark silicon nanocrystals, i.e., the nanocrystals that are not able to radiatively recombine after absorption of a photon, is investigated by combining measurements of external and internal quantum efficiencies. The study is conducted on samples prepared by co-sputtering and subsequent heat treatments. We show that the external quantum efficiency is mainly limited by the presence of dark nanocrystals, which induce losses after direct excitation and also, as we propose, by indirect excitation enabled by energy migration. The percentage of dark nanocrystals can be decreased by high quality surface passivation as a result of low-temperature annealing in ambients of O 2 and H 2 . By using a non-passivated sample as a reference, the relation between the size of a nanocrystal and its probability of being dark is studied. Larger nanocrystals are demonstrated to function more likely as dark centers. The study shows that high external quantum efficiencies of Si nanocrystal ensembles can be realized for small, well passivated Si nanocrystals under suppression of excitation diffusion. V C 2013 AIP Publishing LLC. [http://dx

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“…Details of sample preparation can be found in Ref. 10. Samples were optically characterized by photoluminescence (PL), using a standard configuration featuring tunable pulsed (5 ns) excitation in the visible and time-resolved detection with a photomultiplier tube.…”

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confidence: 99%

Increased carrier generation rate in Si nanocrystals in SiO2 investigated by induced absorption

Boer

Trinh

Timmerman

et al. 2011

Applied Physics Letters

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We report on investigations of optical generation of carriers in Si nanocrystals embedded in SiO 2 matrix by time-resolved induced absorption technique. Results obtained for excitation below and above twice the bandgap energy hm < 2E g and hm > 2E g show very similar decay characteristics (within s resolution % 100 fs). When intensity of the signal is correlated to number of generated excitons, it is found that for the high photon energy excitation, carrier generation rate is considerably enhanced. These results are discussed in terms of carrier multiplication reported previously for semiconductor nanocrystals and photoluminescence quantum yield measurements for similar materials. V C 2011 American Institute of Physics. [doi:10.1063/1.3622308] In the last two decades, silicon nanocrystals (Si-NCs) have been frequently investigated. Following intensive studies, exciting application prospects for Si-NCs have been identified in photonics, 1 medicine, 2 and in photovoltaics (PV). 3 A particularly interesting feature of semiconductor NCs relates to the effect of quantum confinement on the impact excitation-a process in which a high energy free carrier relaxes by inducing band-to-band transitions. In that way, additional electron-hole pairs are created, and the process is frequently termed carrier multiplication (CM). For PV applications, generation of multiple electron-hole pairs by absorption of a single high-energy photon enables more efficient light-to-electricity conversion, as part of the energy otherwise lost to heat is converted into free carrier population. 4 It has been suggested that in NCs, the CM rate could be enhanced and its threshold energy reduced due to (1) increased Coulomb interaction between carriers, (2) relaxation of momentum conservation, and (3) possible reduction of the carrier-phonon scattering rate. 5 In line with these expectations, enhanced CM has been reported for NCs of different semiconducting materials 6-8 including colloidal SiNCs. 9 These results were typically obtained from investigations of carrier dynamics by induced absorption (IA), where the CM effect was identified by a fast decay component appearing due to Auger interaction of multiple excitons nigh within the same NC.Here, we report on investigations of carrier generation rate upon optical absorption in dense solid-state dispersions of small Si-NCs of high crystalline quality in a SiO 2 -matrix with average diameters d NC ¼ 2.5, 3, 4, and 5.5 nm. The samples were prepared by radio-frequency co-sputtering followed by high-temperature annealing. Details of sample preparation can be found in Ref. 10. Samples were optically characterized by photoluminescence (PL), using a standard configuration featuring tunable pulsed (5 ns) excitation in the visible and time-resolved detection with a photomultiplier tube. For IA experiments, a conventional pump-probe setup was employed, comprising an optical parametric amplifier, pumped by a chirped-pulse amplified Ti:Sapphire laser, with a repetition rate of f ¼ 1 kHz and $100 fs resolutio...

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Size-dependent photoluminescence from surface-oxidized Si nanocrystals in a weak confinement regime

Cited by 328 publications

References 24 publications

The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO₂:nc-Si

The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO₂:nc-Si

Spectroscopic investigations of dark Si nanocrystals in SiO2 and their role in external quantum efficiency quenching

Increased carrier generation rate in Si nanocrystals in SiO2 investigated by induced absorption

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Size-dependent photoluminescence from surface-oxidized Si nanocrystals in a weak confinement regime

Cited by 328 publications

References 24 publications

The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO2:nc-Si

The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO2:nc-Si

Spectroscopic investigations of dark Si nanocrystals in SiO2 and their role in external quantum efficiency quenching

Increased carrier generation rate in Si nanocrystals in SiO2 investigated by induced absorption

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Product

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The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO₂:nc-Si

The Influence of Annealing Temperature and Doping on the Red/Near-Infrared Luminescence of Ion Implanted SiO₂:nc-Si