Papers by Keyword: Pulsed Laser Ablation

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Authors: Xin Yu Tan, Zhong Long Wang, Mao Feng, Yine Zhou
Abstract: A numerical simulation is proposed to study the dynamics expansion characteristics during the material irradiated by a high-intensity laser beam.The ionization effect and the local mass and momentum conservations for plasma expansion are considered in this model. As an example of carbon target, the plasma flow dynamics into a vacuum, like ionization degree, plasma number density and space pressure are studied in detail. The results show the plasma temperature strongly affects the ionization fraction and the ionization effect evidently influences the plasma dynamic expansion behavior. The space pressure of plasma decreases along with the plasma expansion.
382
Authors: Valery A. Svetlichnyi, Darya A. Goncharova, Anastasiia V. Shabalina, Ivan N. Lapin, Anna L. Nemoykina
Abstract: Colloidal solutions of copper (I) oxide, Cu2O, were obtained by pulsed laser ablation of metallic copper target in distilled water using fundamental harmonic of Nd:YAG laser (1064 nm, 7 ns, 20 Hz). Nanocolloids obtained were applied to cotton fabric. Nanoparticles composition and structure were studied by UV-Vis and Raman spectroscopy, transmission and scanning electron microscopy, and XRD. Antibacterial activity of Cu2O nanoparticles on cotton fabric to E.coli bacteria was demonstrated in comparison with zinc oxide nanoparticles.
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Authors: Bing Xu, Ren Guo Song, Chao Wang
Abstract: In order to study the effects of laser fluence on silver nanoparticles colloid, the silver nanoparticles colloid was prepared by pulsed laser ablation of silver target for 10min in distilled water at different laser fluence. The particles size,morphologies and absorption spectroscopy of the obtained nanoparticles colloid were characterized by ultraviolet to visible (UV-Vis) spectrometer and transmission electron microscopy (TEM), the average diameter and its distribution were analyzed by Image-ProPlus software. The results shown that the average diameter of the silver nanoparticles prepared at the laser fluence of 4.2J/cm2 was the smallest (D=17.54nm), also, the distribution of particle size was narrowest (=36.86nm) and the morphologies were more homogeneous. It was confirmed that the nanoparticles size and shape could be controlled by pulsed laser ablation parameters.
747
Authors: Bing Xu, Ren Guo Song, Chao Wang, Wang Zhao He
Abstract: The silver nanoparticles colloid was prepared by pulsed laser ablation in distilled water under various laser repetition rates. The particles size, morphologies and absorption spectroscopy of the obtained nanoparticles colloids were characterized by ultraviolet to visible (UV-Vis) spectrometer and transmission electron microscopy (TEM). The average diameter and its distribution were analyzed by Image-ProPlus software. The results showed that the average diameter of the silver nanoparticles prepared at the laser repetition rate of 10 HZ was the smallest (D=29.75 nm), also, the distribution of particle size decreases with increasing the laser repetition rate.
1888
Authors: Bing Xu, Ren Guo Song
Abstract: Ag nanoparticles colloids have been fabricated by pulsed laser ablation in various liquids. The particle size, morphology and absorption spectroscopy of the obtained nanoparticles colloids were characterized by ultraviolet to visible (UV-Vis) spectrophotometer and transmission electron microscopy (TEM), the average diameter and its distribution were analyzed by Image-ProPlus software. The results showed that the Ag nanoparticles with best characterization are those produced at the repetition rate of 10Hz and laser fluence of 4.2J/cm2 by ablating for 7.5min in the distilled water, with the least average diameter(D=14.48 nm), the narrowest distribution of particles size (=25.8 nm) and more homogeneous morphologies. The effects of experimental conditions on the silver nanoparticles colloid can be explained by fragmentation and melting induced aggregation of colloidal particles by self-absorption of laser pulses.
675
Authors: A. Perrone, L. Cultrera, S. Duhalde
Abstract: The morphological changes and corresponding plume deflection effect during long laser (XeCl excimer laser, λ=308 nm, τ=30 ns) irradiation of Al target have been investigated,and results showed that, a the number of laser pulses per site increases, the target morphology changes and produces a visible deviation of the plasma plume up to 5º. Scanning electron spectroscopy analys of the target surface related the plume deflection angle to the target morphology and the number of laser pulses per site. Typically well-defined columnar structures oriented along the laser beam direction were observed on the target surface. The plume created during the laser ablation was clearly visible to the naked eye and was recorded by a digital camera. Detailed studies were also performed on the ablation rate at different laser fluences (4.6 J/cm2-12.5 J/cm2). The morphologies and the thickness of the Al thin films deposited on Si substrates during the present laser ablation experiments were also studied. Finally, the scenario explaining the formation of columnar structure on target surface responsible for the plume deflection effect will be discussed.
789
Authors: L. D’Alessio, G. Pace, R. Teghil
Abstract: In this work the microscopic morphology of titanium carbide thin films, obtained by pulsed laser ablation, are studied. A target of TiC has been ablated in vacuum with a laser Twinkle of Light Conversion Ltd. capable to furnish impulses of 250 fs, with a repetition frequency of 10 Hz at the wavelength of 527 nm. The ablated material has been deposited on (111) oriented silicon substrates, maintained at ambient temperature during the film deposition. Digital images of the films have been acquired through scanning electron microscopy. Numerical codes have been developed in Matlab environment, to obtain a three-dimensional reconstruction of the film surfaces starting from the bidimensional images. On such reconstruction a multi-scale analysis has been performed by hilbertian methods, for the characterization of the surface roughness and to study the distribution of the deposited nanoparticles. The results show that the free surface of the film has a characteristics scale invariance that allow the description by multi-fractal techniques. In particular the fractal dimension of the surface has been calculated in nanometric range. The investigation allows to identify some proper morphological indicators to characterize the film geometry and parameterize the tribological properties of the interface. These indicators, if opportunely employed together with classical methods of analysis, furnish a further tool for better understanding the complex nature of the deposits.
177
Authors: Bing Xu, Ren Guo Song, Chao Wang
Abstract: Ag, Au and Ti metal nanoparticles colloids have been prepared by pulsed laser ablation in various liquids. The particle size and morphology of the obtained nanoparticles colloids were characterized by transmission electron microscopy (TEM), the average diameter and its distribution were analyzed by Image-ProPlus software. The results showed that the Au nanoparticles were of the best characterization, the average diameter was the smallest (D=8.79 nm), and also, the distribution of particle size was the narrowest (=17.5 nm) and the morphologies were more homogeneous.
648
Authors: Wuttichai Phae-Ngam, Voravit Kosalathip, T. Kumpeerapun, Pichet Limsuwan, A. Dauscher
Abstract: A long pulsed laser ablation with a moving target at high speed technique was applied to prepare tellurium nanoparticles from a tellurium target under argon gas at atmospheric pressure. The prepared nanoparticles were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), and X-ray diffraction (XRD). The influence of the moving speed of the target on the size, morphology and crystallographic structure of the nanoparticles was investigeated. The results show that for the target moving at high speed without burning of the target the production of isolated nanoparticles is obtained. The diameter of the nanoparticles is ranging from 30 to 200 nm.
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