Optical Properties of Silicon Nanocrystallites Prepared   by Excimer Laser Ablation in Inert Gas

The main objective of this study is to explain the experimental observations. To simulate material ablation, plume formation and its evolution, we developed a combined molecular dynamics (MD) and direct simulation Monte Carlo (DSMC) computational study of laser ablation plume evolution. The first process of the material ablation is described by the MD method. The expansion of the ejected plume is modelled by the DSMC method. To better understand the formation and the evolution of nanoparticles present in the plume, we first used separate MD simulations to analyse the evolution of a cluster in the presence of background gas with different properties (density, temperature). In particular, we examine evaporation and growth reactions of a cluster with different size and initial temperature. As a result of MD calculations, we determinate the influence of the background gas parameters on the nanoparticles. The reactions rates such as evaporation/condensation, which are obtained by MD simulations, are directly transferred to the DSMC part of our combined model. Finally, several calculations performed by using MD-DSMC model demonstrate both plume dynamics and longer-time cluster evolution. Calculations results are compared with experimental findings.

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“…(1) simple collision with the rate of collisions coll ; (2) where e and c are respectively the evaporation and condensation rates.…”

Section: Cluster Evolutionmentioning

confidence: 99%

Formation of nanoparticles by short and ultra-short laser pulses

Gouriet

Itina

Noël

et al. 2008

High-Power Laser Ablation VII

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“…This technique, known as pulsed laser ablation (PLA), has become a promising method of the synthesis of nanoclusters for photonics, electronics and medicine (Movtchan et al, 1995;Yamada et al, 1996;Makimura et al, 1996;Geohegan et al, 1998;Albert et al, 2003). The PLA method has several advantages compared to more traditional techniques.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Nanoparticle Formation by Laser Ablation

Itina¹

2010

Laser Pulse Phenomena and Applications

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“…LIB methods are important for a more complete understanding of the photoinduced chemical vapor processes to produce thin nanostructured films of hydrogenated amorphous silicon ͑a-Si: H͒. These processing technologies generally imply deposition of a film on a substrate as, for example, in experiments with magnetron sputtering, 3 plasma deposition, 4 laser ablation, [5][6][7] and electric spark processing of a silicon wafer. 8 LIB of silane ͑SiH 4 ͒ has been largely used in laser-induced chemical vapor deposition ͑CVD͒ and plasma-enhanced CVD for obtaining amorphous and hydrogenated silicon films.…”

Section: Introductionmentioning

confidence: 99%

Laser-induced breakdown spectroscopy of trisilane using infrared CO2 laser pulses

Camacho

Poyato

Díaz

et al. 2007

Journal of Applied Physics

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Synthesis and photoluminescence of fluorinated graphene quantum dots Appl. Phys. Lett. 102, 013111 (2013) The luminescence characteristics of CsI(Na) crystal under α and X/γ excitation J. Appl. Phys. 113, 023101 (2013) Structural and optoelectronic properties of Eu2+-doped nanoscale barium titanates of pseudo-cubic form J. Appl. Phys. 112, 124321 (2012) Quantum yield of luminescence of Ag nanoclusters dispersed within transparent bulk glass vs. glass composition and temperature Appl. Phys. Lett. 101, 251106 (2012) Additional information on J. Appl. Phys. The plasma produced in trisilane ͑Si 3 H 8 ͒ at room temperature and pressures ranging from 50 to 10 3 Pa by laser-induced breakdown ͑LIB͒ has been investigated. The ultraviolet-visible-near infrared emission generated by high-power IR CO 2 laser pulses in Si 3 H 8 has been studied by means of optical emission spectroscopy. Optical breakdown threshold intensities in trisilane at 10.591 m for laser pulse lengths of 100 ns have been measured as a function of gas pressure. The strong emission observed in the plasma region is mainly due to electronic relaxation of excited atomic H and Si and ionic fragments Si + , Si 2+ , and Si 3+ . An excitation temperature T exc = 5600± 300 K was calculated by means of H atomic lines assuming local thermodynamic equilibrium. The physical processes leading to LIB of trisilane in the power density range 0.28 GW cm −2 Ͻ J Ͻ 3.99 GW cm −2 have been analyzed. From our experimental observations we can propose that, although the first electrons must appear via multiphoton ionization, electron cascade is the main mechanism responsible for the breakdown in trisilane.

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Optical Properties of Silicon Nanocrystallites Prepared by Excimer Laser Ablation in Inert Gas

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Formation of nanoparticles by short and ultra-short laser pulses

Formation of nanoparticles by short and ultra-short laser pulses

Mechanisms of Nanoparticle Formation by Laser Ablation

Laser-induced breakdown spectroscopy of trisilane using infrared CO2 laser pulses

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