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Synthesis of nanocrystals by discharges in liquid nitrogen from Si-Sn sintered electrode.

Kabbara H, Noël C, Ghanbaja J, Hussein K, Mariotti D, Švrček V, Belmonte T - Sci Rep (2015)

Bottom Line: The presence of both vapours does not lead to the synthesis of alloyed nanocrystals but to the synthesis of separate nanocrystals of silicon and tin with average sizes of 10 nm.The synthesis of an am-Si0.95Sn0.05 phase around large silicon crystals (~500 nm) decorated by β-Sn spheroids is achieved if the current flowing through electrodes is high enough.When the sintered electrode is hit by powerful discharges, some grains are heated and tin diffuses in the large silicon crystals.

View Article: PubMed Central - PubMed

Affiliation: Université de Lorraine, Institut Jean Lamour, UMR CNRS 7198, NANCY, F-54042, France.

ABSTRACT
The synthesis feasibility of silicon-tin nanocrystals by discharges in liquid nitrogen is studied using a Si-10 at % Sn sintered electrode. Time-resolved optical emission spectroscopy shows that silicon and tin melt almost simultaneously. The presence of both vapours does not lead to the synthesis of alloyed nanocrystals but to the synthesis of separate nanocrystals of silicon and tin with average sizes of 10 nm. These nanocrystals are transformed into amorphous silicon oxide (am-SiO2) and β-SnO2 by air oxidation, after evaporation of the liquid nitrogen. The synthesis of an am-Si0.95Sn0.05 phase around large silicon crystals (~500 nm) decorated by β-Sn spheroids is achieved if the current flowing through electrodes is high enough. When the sintered electrode is hit by powerful discharges, some grains are heated and tin diffuses in the large silicon crystals. Next, these grains are shelled and fall into the dielectric liquid.

No MeSH data available.


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Time evolution of three selected lines observed between 282 and 292 nm.
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f6: Time evolution of three selected lines observed between 282 and 292 nm.

Mentions: Time-resolved optical emission spectroscopy was performed with a ballast resistance of 10 kΩ only (i.e. a current of 1 A). Si I, Si II and Sn I transition lines were observed (Fig. 5). Conversely, no N I lines were found. This lack of nitrogen lines was already reported15. Nitrogen seems not having a chemical role in the synthesis process. By selecting three lines appearing within a short range of wavelengths (see Supplemental Material 6)–one of Si I at 288.2 nm, and two of Sn I at 284 and 286.3 nm –, we could record the time evolution of these lines at one stroke (Fig. 6).


Synthesis of nanocrystals by discharges in liquid nitrogen from Si-Sn sintered electrode.

Kabbara H, Noël C, Ghanbaja J, Hussein K, Mariotti D, Švrček V, Belmonte T - Sci Rep (2015)

Time evolution of three selected lines observed between 282 and 292 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664926&req=5

f6: Time evolution of three selected lines observed between 282 and 292 nm.
Mentions: Time-resolved optical emission spectroscopy was performed with a ballast resistance of 10 kΩ only (i.e. a current of 1 A). Si I, Si II and Sn I transition lines were observed (Fig. 5). Conversely, no N I lines were found. This lack of nitrogen lines was already reported15. Nitrogen seems not having a chemical role in the synthesis process. By selecting three lines appearing within a short range of wavelengths (see Supplemental Material 6)–one of Si I at 288.2 nm, and two of Sn I at 284 and 286.3 nm –, we could record the time evolution of these lines at one stroke (Fig. 6).

Bottom Line: The presence of both vapours does not lead to the synthesis of alloyed nanocrystals but to the synthesis of separate nanocrystals of silicon and tin with average sizes of 10 nm.The synthesis of an am-Si0.95Sn0.05 phase around large silicon crystals (~500 nm) decorated by β-Sn spheroids is achieved if the current flowing through electrodes is high enough.When the sintered electrode is hit by powerful discharges, some grains are heated and tin diffuses in the large silicon crystals.

View Article: PubMed Central - PubMed

Affiliation: Université de Lorraine, Institut Jean Lamour, UMR CNRS 7198, NANCY, F-54042, France.

ABSTRACT
The synthesis feasibility of silicon-tin nanocrystals by discharges in liquid nitrogen is studied using a Si-10 at % Sn sintered electrode. Time-resolved optical emission spectroscopy shows that silicon and tin melt almost simultaneously. The presence of both vapours does not lead to the synthesis of alloyed nanocrystals but to the synthesis of separate nanocrystals of silicon and tin with average sizes of 10 nm. These nanocrystals are transformed into amorphous silicon oxide (am-SiO2) and β-SnO2 by air oxidation, after evaporation of the liquid nitrogen. The synthesis of an am-Si0.95Sn0.05 phase around large silicon crystals (~500 nm) decorated by β-Sn spheroids is achieved if the current flowing through electrodes is high enough. When the sintered electrode is hit by powerful discharges, some grains are heated and tin diffuses in the large silicon crystals. Next, these grains are shelled and fall into the dielectric liquid.

No MeSH data available.


Related in: MedlinePlus