Quantum confinement effect of silicon nanocrystals <i>in situ</i> grown in silicon nitride films

Kim, Tae Youb; Park, Nae Man; Kim, Kyung Hyun; Sung, Gun Yong; Ok, Young-Woo; Seong, Tae Yeon; Choi, Cheol Jong

doi:10.1063/1.1814429

Cited by 286 publications

(131 citation statements)

References 18 publications

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“…Second, another narrow emission peak with a much higher intensity is present at 410 nm. According to previous reports, this emission is characteristic for the SiQDs with dimensions below 10 nm [50,51]. It is important to note that the highest intensity of the SiQDs emission was obtained by excitation at 330 nm, the same wavelength as for the polysilane structure.…”

Section: Spectroscopy Of Nqdmentioning

confidence: 97%

Fluorescence detection system based on silicon quantum dots–polysilane nanocomposites

Săcărescu¹,

Roman²,

Săcărescu³

et al. 2016

Express Polym. Lett.

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Abstract.A dual channel fluorescence system that combines the optical properties of silicon quantum dots-polysilane nanocomposites with those of 2-(4-chlorophenyl)-6-(thiophen-2-yl)pyridine, a fluorescent cytotoxic agent, is presented. The system is capable to alternatively trigger emission signals at two different wavelengths by excitation at a single wavelength. For this purpose a highly stable colloidal dispersion of silicon quantum dots-polysilane nanocomposite is prepared by a one-pot synthetic method using microwave-activated Wurtz coupling of organochlorosilanes. The size and shape of the silicon quantum dots within the polysilane thin film are studied by TEM. The colloidal dispersions are investigated by SAXS, which evidences that polysilane plays also a role as stabilizing agent to prevent aggregation. UV-vis spectrophotometry of the silicon quantum dots-polysilane nanocomposites in the presence of 2-(4-chlorophenyl)-6-(thiophen-2-yl)pyridine is used to define the active wavelength range and establish the fluorescence detection method.

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Section: Spectroscopy Of Nqdmentioning

confidence: 97%

Fluorescence detection system based on silicon quantum dots–polysilane nanocomposites

Săcărescu¹,

Roman²,

Săcărescu³

et al. 2016

Express Polym. Lett.

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“…Therefore, the stronger the confinement, the more efficient is the CM process. 19 Moreover, apart from widening the electronic bandgap (in silicon scaling with the square of the diameter 20 ), the same quantum confinement relaxes the momentum conservation requirement in optical transitions through Heisenberg's uncertainty relation, thus considerably enhancing the probability of band-to-band transitions for indirect bandgap materials (such as silicon and germanium), lowering the radiative recombination time constant down to the 10-ms range. This relaxation of momentum conservation also enhances CM and Auger recombination.…”

Section: Introductionmentioning

confidence: 99%

Carrier multiplication in germanium nanocrystals

et al. 2015

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Carrier multiplication is demonstrated in a solid-state dispersion of germanium nanocrystals in a silicon-dioxide matrix. This is performed by comparing ultrafast photo-induced absorption transients at different pump photon energies below and above the threshold energy for this process. The average germanium nanocrystal size is approximately 5-6 nm, as inferred from photoluminescence and Raman spectra. A carrier multiplication efficiency of approximately 190% is measured for photo-excitation at 2.8 times the optical bandgap of germanium nanocrystals, deduced from their photoluminescence spectra.

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“…The observed particle range represents QDs with energy band gap (E g ) in the range of 1.34-2.47 eV as calculated using Eq. 1 [3]:…”

Section: Experimentationmentioning

confidence: 99%

“…Quantum confinement effect, a feature of QDs, is exhibition of discrete energy level by a nanoparticle smaller than exciton Bohr radius [3]. When Si nanoparticles are spaced sufficiently close together, wave functions of quantum confined carriers in adjacent dots overlap.…”

Section: Introductionmentioning

confidence: 99%

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Silicon quantum dot solar cell using top-down approach

Kale

Solanki

2015

Int Nano Lett

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The current trend of research in the area of third-generation photovoltaics is to increase the efficiency of solar cell device adopting alternate and novel ways such as use of quantum dots to absorb maximum solar spectrum. A new and low-cost top-down approach to fabricate silicon quantum dot solar cell (QDSC) using spin coating of Si QDs embedded in flowable oxide is proposed. Si QDs with diameter smaller than 8 nm were synthesized using topdown approach by ultrasonication of freestanding porous silicon films obtained by anodization of Si. Systematic measurements of current density-voltage (J-V), capacitance-voltage (C-V) and external quantum efficiency (EQE) were carried out. The QDSC exhibits photovoltaic effect, hysteresis in C-V characteristics and improved EQE performance in short wavelength as compared with a reference c-Si cell with same structure, but without QD layer. The novelty and simplicity of the QDSC fabrication process make these results important.

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Quantum confinement effect of silicon nanocrystals in situ grown in silicon nitride films

Cited by 286 publications

References 18 publications

Fluorescence detection system based on silicon quantum dots–polysilane nanocomposites

Fluorescence detection system based on silicon quantum dots–polysilane nanocomposites

Carrier multiplication in germanium nanocrystals

Silicon quantum dot solar cell using top-down approach

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