Titel
The influence of the fluid nature on femtosecond laser ablation properties of a SiO2/Si target and synthesis of ultrafine-grained Si nanoparticles
Autor*in
Gerhard Liedl
Institute for Production Engineering and Laser Technology, Vienna University of Technology
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Abstract
Nanocrystalline silicon nanoparticles with a median crystallite size of 3–4 nm and several crystalline phases and defects (e.g. twin boundary) were produced by femtosecond laser processing of a SiO2/Si target in various organic fluids. Furthermore, a nanoscaled amorphous oxide layer and a few atomic layers of a graphite shell were detected in ethanol and 2-butanol correspondingly. The ultrafast laser pulses may manipulate nanostructures at the atomic level and generate a high density of defects; this may be correlated with significant thermal stresses on nanoparticles and rapid condensation of primary nanoparticles with high cooling rates. Size distribution width and a polydispersity index slightly increased with increasing laser fluence in ethanol. In 2-butanol, the maximum ablation volume was observed. The specific ablation rates in 2-butanol and ethanol were approximately five times higher than n-hexane. The lowest ablation efficiency in n-hexane can be associated with femtosecond laser-induced photolysis and pyrolysis of solvent molecules, as total energy deposition on the material may be reduced due to the formation of carbonaceous products. The roughened zones (average roughness of ∼400 nm) in circumferences of the ablated craters in 2-butanol may be related to a correlation between the erosive power of the vapour bubble collapse and higher pressure at the bubble wall in relatively high dynamic viscosity fluids. Furthermore, sputtering of a pristine surface by releasing nanoparticles from the collective collapse of up-flow vapour bubbles can also contribute to the generation of roughened regions.
Stichwort
General EngineeringGeneral Materials ScienceGeneral ChemistryAtomic and Molecular Physics, and OpticsBioengineering
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
Nanoscale Advances
Band
2
Ausgabe
9
ISSN
2516-0230
Erscheinungsdatum
2020
Seitenanfang
3991
Seitenende
4002
Publication
Royal Society of Chemistry (RSC)
Erscheinungsdatum
2020
Zugänglichkeit
Rechte
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