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Open AccessFeature PaperArticle

Tailoring Photoluminescence from Si-Based Nanocrystals Prepared by Pulsed Laser Ablation in He-N2 Gas Mixtures

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MEPHI, Institute of Engineering Physics for Biomedicine (PhysBio), Kashirskoe sh. 31, 115409 Moscow, Russia
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Lebedev Physical Institute of the Russian Acad. Sci., Leninskiy Pr. 53, 119991 Moscow, Russia
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MEPHI, Institute of Nanoengineering in Electronics, Spintronics and Photonics, Kashirskoe sh. 31, 115409 Moscow, Russia
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Prokhorov General Physics Institute of the Russian Acad. Sci., Vavilova St. 38, 117942 Moscow, Russia
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Lomonosov Moscow State University, Physics Dep., Leninskie Gory 1, 119991 Moscow, Russia
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Aix Marseille Univ, CNRS, LP3, Campus de Luminy, Case 917, 13288 Marseille, France
*
Authors to whom correspondence should be addressed.
Academic Editor: Tatiana E. Itina
Molecules 2020, 25(3), 440; https://doi.org/10.3390/molecules25030440
Received: 8 December 2019 / Revised: 14 January 2020 / Accepted: 19 January 2020 / Published: 21 January 2020
(This article belongs to the Special Issue Laser Synthesis)
Using methods of pulsed laser ablation from a silicon target in helium (He)-nitrogen (N2) gas mixtures maintained at reduced pressures (0.5–5 Torr), we fabricated substrate-supported silicon (Si) nanocrystal-based films exhibiting a strong photoluminescence (PL) emission, which depended on the He/N2 ratio. We show that, in the case of ablation in pure He gas, Si nanocrystals exhibit PL bands centered in the “red - near infrared” (maximum at 760 nm) and “green” (centered at 550 nm) spectral regions, which can be attributed to quantum-confined excitonic states in small Si nanocrystals and to local electronic states in amorphous silicon suboxide (a-SiOx) coating, respectively, while the addition of N2 leads to the generation of an intense “green-yellow” PL band centered at 580 nm. The origin of the latter band is attributed to a radiative recombination in amorphous oxynitride (a-SiNxOy) coating of Si nanocrystals. PL transients of Si nanocrystals with SiOx and a-SiNxOy coatings demonstrate nonexponential decays in the micro- and submicrosecond time scales with rates depending on nitrogen content in the mixture. After milling by ultrasound and dispersing in water, Si nanocrystals can be used as efficient non-toxic markers for bioimaging, while the observed spectral tailoring effect makes possible an adjustment of the PL emission of such markers to a concrete bioimaging task. View Full-Text
Keywords: pulsed laser ablation in gases; pulsed laser deposition; silicon nanoparticles; silicon quantum dots; silicon oxynitride; photoluminescence; quantum confinement; bioimaging pulsed laser ablation in gases; pulsed laser deposition; silicon nanoparticles; silicon quantum dots; silicon oxynitride; photoluminescence; quantum confinement; bioimaging
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Fronya, A.A.; Antonenko, S.V.; Kharin, A.Y.; Muratov, A.V.; Aleschenko, Y.A.; Derzhavin, S.I.; Karpov, N.V.; Dombrovska, Y.I.; Garmash, A.A.; Kargin, N.I.; Klimentov, S.M.; Timoshenko, V.Y.; Kabashin, A.V. Tailoring Photoluminescence from Si-Based Nanocrystals Prepared by Pulsed Laser Ablation in He-N2 Gas Mixtures. Molecules 2020, 25, 440.

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