The influence of the fluid nature on femtosecond laser ablation properties of a SiO₂/Si target and synthesis of ultrafine-grained Si nanoparticles

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.

Near-Infrared Femtosecond Laser Ablation of Au-Coated Ni: Effect of Organic Fluids and Water on Crater Morphology, Ablation Efficiency and Hydrodynamic Properties of NiAu Nanoparticles

“…For PLAL in n-hexane, the smallest crater diameter, depth, ablation volume and thus specific ablation rate were observed. This finding is similar to that of femtosecond laser ablation of SiO 2 /Si in n-hexane [ 47 ]. It may thus correlate with pyrolysis and photolysis of high-carbon-number solvents and the formation of carbon products that impact the ablation efficiency, since ablation of Fe [ 46 ] targets in toluene was also low.…”

“…An average surface roughness of 2.18 µm and 1.35 µm was determined for cones and cracks, respectively. This is similar to femtosecond laser ablation of a SiO 2 /Si target in 2-butanol, which had shown similar structures on the top of the craters [ 47 ]. Since a horizontal beam delivery was used herein, the beam deviation towards the top of the craters was more pronounced.…”

“…An overall comparison of ablation properties of femtosecond-laser-drilled Au-coated Ni for various fluids is presented in Figure 7 . Former studies on femtosecond laser processing of Fe [ 46 ] and SiO 2 /Si [ 47 ] reported the smallest spot size in toluene and n-hexane, correspondingly, while using other fluids led to an increase in the ablation threshold and laser fluence. The highest specific ablation rate and ablation volume were obtained in 2-butanol, analogous to a previous study [ 47 ].…”

“…Former studies on femtosecond laser processing of Fe [ 46 ] and SiO 2 /Si [ 47 ] reported the smallest spot size in toluene and n-hexane, correspondingly, while using other fluids led to an increase in the ablation threshold and laser fluence. The highest specific ablation rate and ablation volume were obtained in 2-butanol, analogous to a previous study [ 47 ]. This may correlate with the deposition of carbonaceous products in the crater, increasing the laser absorption on the surface [ 24 , 25 ].…”

“…Among multiple factors in ultrafast processing, the ablation environment significantly affects the observables. The chemical composition of the liquid not only affects the ablation efficiency [ 46 , 47 ] but also affects the chemical composition of either targets or NPs, since laser interaction with liquids can lead to solvent photolysis and pyrolysis [ 23 , 47 , 48 , 49 , 50 ]. However, only a few studies on materials in liquids exist which describe the influence of the liquid environment on multi-pulse femtosecond ablation efficiency and crater morphology [ 46 , 47 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ], so this aspect calls for further experimental investigations.…”