The influence of the fluid nature on femtosecond laser ablation properties of a SiO2/Si target and synthesis of ultrafine-grained Si nanoparticles. Issue 9 (16th July 2020)

• Record Type: Journal Article
• Authors: Lasemi, Niusha; Rentenberger, Christian; Liedl, Gerhard; Eder, Dominik
• Is Part Of: Nanoscale advances. Volume 2:Issue 9(2020)
• Page Start: 3991
• Page End: 4002
• Publication Date: 2020-07-16
• Subjects: 620.5
• DOI: 10.1039/d0na00317d
• Languages: English
• ISSNs: 2516-0230

Abstract

Abstract : Femtosecond laser assisted formation of ultrafine-grained Si NPs with a high density of defects. This can correlate with significant thermal stresses on primary NPs, fast cooling of ejected liquid droplets and incomplete ripening processes. 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.