Blue-Green Photoluminescence from Ultrafine Colloidal Si Particles in 2-Propanol

Iwasaki, Shingo; Ida, Takashi; Kimura, Kazuhiro

doi:10.1143/jjap.35.l551

Cited by 11 publications

(4 citation statements)

References 20 publications

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“…10 depicts the intermediate part of our data, and the data of Kanemitsu 8 and Iwasaki et al 6 Here two scenarios can be examined. The first presumes that the low energy emissions ͑and thereby all emissions in the lower shaded region͒ are due to Si bandgap emission, i.e., indirect recombination.…”

Section: Comparison With Earlier Luminescence Resultsmentioning

confidence: 97%

“…Si nanoclusters have been produced by aerosol techniques, 2 plasma deposition, 3 sputtering, 4 spark ablation 5 and grown as colloids, 6 or in glass matrices by a variety of approaches 7-9 including ion implantation 9 followed by high temperature annealing; however, all of these techniques produce a large distribution of cluster sizes resulting in very broad optical absorption and PL features which limit usefulness and make definitive interpretation in terms of quantum confinement and other mechanisms difficult.…”

Section: Introductionmentioning

confidence: 99%

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Optical and electronic properties of Si nanoclusters synthesized in inverse micelles

1999

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Highly crystalline, size-selected silicon (Si) nanocrystals in the size range 2-10 nm were grown in inverse micelles and their optical absorption and photoluminescence (PL) properties were studied. High resolution TEM and electron diffraction results show that these nanocrystals retain their cubic diamond stuctures down to sizes -4 nm in diameter, and optical absorption data suggest that this structure and bulk-like properties are retained down to the smallest sizes produced (-1.8 nm diameter containing about 150 Si atoms). High pressure liquid chromatography techniques with on-line optical and electrical diagnostics were developed to purify and separate the clusters into pure, monodisperse populations. The optical absorption revealed features associated with both the indirect and direct bandgap transitions, and these transitions exhibited different quantum confinement effects. The indirect bandgap shifts from 1.1 eV in the bulk to -2.1 eV for nanocrystals -2 nm in diameter and the direct transition at T(Tz -TIS) blue shifts by 0.4 eV from its 3.4 eV bulk value over the same size range.Tailorable, visible, room temperature PL in the range 700-350 nm (1.8 -3.5 eV) was observed from these nanocrystals. The most intense PL was in the violet region of the spectrum (-400 nm) and is attributed to direct electron-hole recombination. Other less intense PL peaks are attributed to surface state and to indirect bandgap recombination. The results are compared to earlier work on Si clusters grown by other techniques and to the predictions of various model calculations.Currently, the wide variations in the theoretical predictions of the various models along with considerable uncertainties in experimental size determination for clusters less than 3-4 nm, make it difficult to select among competing models.-1-

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Section: Comparison With Earlier Luminescence Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Optical and electronic properties of Si nanoclusters synthesized in inverse micelles

1999

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“…That is to say, the absorption threshold shifted to the lower-energy side with an increase of size as has already been reported. 18 On the other hand, the emission main band at 2.58 eV was held constant for all sizes, indicating a purely localized character for PL in the blue energy region. The experimentally obtained PL intensity I together with those normalized by absorbance, proportional to the quantum yield, are listed in Table I taken from 3.7 nm sample as a reference.…”

Section: Resultsmentioning

confidence: 90%

“…This term is dropped in the following discussion because the absorption energy by a surface localized site should be independent of the size of a particle; this situation is in contrast to the observation which showed clear size dependence. 18 Moreover, the absorption energy by a local site in silicon oxide is normally higher than the observed value, and the cross section of absorption seems to be very small for a local state. The second term stands for crystallite absorption and emission.…”

Section: Discussionmentioning

confidence: 85%

Size dependence of the quantum yield of photoluminescence from silicon nanocolloids

Kimura

Iwasaki

1998

Journal of Applied Physics

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We have prepared several nanometer-sized silicon colloids in the range from 3.7 to 9.8 nm with a constant weight density 1 mg/ml. The blue-green emission is found to be independent of size contrast to its intensity. The absolute quantum yield as a function of size is determined. From the proposed model that combines surface as well as volume effects, the emission is proved to be from a surface trapped site. The energy transfer efficiency from volume to the site is almost 100% for the 3.7 nm particle.

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Memory Devices

Kolobov¹,

Tominaga²

2012

Chalcogenides

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Blue-Green Photoluminescence from Ultrafine Colloidal Si Particles in 2-Propanol

Cited by 11 publications

References 20 publications

Optical and electronic properties of Si nanoclusters synthesized in inverse micelles

Optical and electronic properties of Si nanoclusters synthesized in inverse micelles

Size dependence of the quantum yield of photoluminescence from silicon nanocolloids

Memory Devices

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