Dust in Plasma II. Effects of Secondary Electrons: Ionization and Surface Emission

Taccogna, F.; Mizzi, Giovanni

doi:10.1002/ctpp.201400040

Cited by 10 publications

(7 citation statements)

References 29 publications

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“…The numerical model [13][14][15] consists of a one-dimensional radial particle-in-cell/Monte Carlo collision (PIC-MCC) simulation of the plasma-dynamics surrounding a growing nanoparticle during the nanoparticle charging phase, that is when nanoparticle seeds are already nucleated and available in a plasma environment.…”

Section: Numerical Model Of Ion-induced Np Growthmentioning

confidence: 99%

On the growth mechanism of nanoparticles in plasma during pulsed laser ablation in liquids

Taccogna

Dell’Aglio

Rutigliano

et al. 2017

Plasma Sources Sci. Technol.

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Particle-in-cell methodology is applied to study the simultaneous charging and coagulation of a nanoparticle, taking into account the self-consistent dynamics of surrounding plasma induced by laser ablation in liquid. The model uses, as an input, plasma temperature and electron number density which are experimentally obtained by high temporally resolved optical emission spectroscopy of the laser-induced plasma in water. Results show the important role of ions in the growth process and of the atom-induced evaporation process for the final nanoparticle size. The competition between different mechanisms of nanoparticle formation in the laser-induced plasma is finally discussed.

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Section: Numerical Model Of Ion-induced Np Growthmentioning

confidence: 99%

On the growth mechanism of nanoparticles in plasma during pulsed laser ablation in liquids

Taccogna

Dell’Aglio

Rutigliano

et al. 2017

Plasma Sources Sci. Technol.

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“…Note that in a plasma with negligible ion dynamics the time of minimum sheath width coincides with the time of minimum voltage drop across the sheath. If an electric field reversal [67] occurs at an electrode, an inverse sheath [68][69][70][71], i.e. a negative space charge, is found at the electrode, when the classical sheath is collapsed.…”

Section: Analytical Modelmentioning

confidence: 99%

The influence of electron reflection/sticking coefficients at the electrodes on plasma parameters in particle-in-cell simulations of capacitive radio-frequency plasmas

Korolov

Derzsi

Schüngel

et al. 2016

Plasma Sources Sci. Technol.

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Capacitive radio-frequency discharges are frequently used to process different materials. In these systems, plasma-surface interactions are known to affect the discharge by particle emission and reflection. In simulations, the corresponding surface coefficients are input parameters, which are often unknown and are, therefore, roughly estimated or ignored. Electron reflection at boundary surfaces is typically either neglected completely or the reflection coefficient, ρ = − S 1 , where S is the sticking coefficient, is assumed to be small, independently of the surface material and its conditions, although it is known to cover a wide range depending on the material. Here, we systematically investigate the effect of changing ρ in particle-in-cell simulations on plasma parameters such as the plasma density, electric field, and ionization rates, in geometrically symmetric single-and dual-frequency discharges operated in argon at a fundamental frequency of 13.56 MHz and at pressures of 5 Pa-20 Pa. We find that the plasma density strongly depends on the reflection coefficient. High coefficients cause electric field reversals during sheath collapse at the electrodes and an enhanced generation of energetic electron beams during sheath expansion, which lead to additional ionization and higher plasma densities. Different reflection coefficients at both electrodes are found to induce a discharge asymmetry that leads to the generation of a DC self-bias and different mean ion energies at the electrodes. In dual-frequency discharges, the electrical generation of the DC self-bias as a function of the phase between two consecutive driving harmonics via the electrical asymmetry effect can be significantly enhanced by choosing electrode materials with different reflection coefficients. In this way the electrical control range of the mean ion energy via phase control is shifted to different energies.

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“…The Monte Carlo model developed is based on the OML theory described in the previous section and it consists of an evolution of numerical models used to study electrostatic probes and dust in plasma (Taccogna, Longo & Capitelli 2003, 2004; Taccogna 2012; Taccogna & Mizzi 2014). The algorithm involves the self-consistent change of charge, surface electric potential and radius of the granule during the expansion of the plasma.…”

Section: Monte Carlo Numerical Modelmentioning

confidence: 99%

Nucleation and growth of nanoparticles in a plasma by laser ablation in liquid

Taccogna

2015

J. Plasma Phys.

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Modelling the nucleation and growth of nanoparticles in liquid-phase laser ablation is very important to optimize and control the size and the structure of nanoparticles. However, the detailed formation process of nanoparticles after laser ablation is still unclear. In the present study we investigated for the first time the kinetic growth of nanoparticles synthesized by laser ablation in water, emphasizing the leading role of the plasma medium and in particular the electrostatic agglomeration due to the charging of the nanoparticle in the plasma plume. The importance of the confining role of the liquid medium on the plasma plume is revealed, showing how an isothermal expansion is able to produce smaller nanoparticles compared to an adiabatic cooling.

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Dust in Plasma II. Effects of Secondary Electrons: Ionization and Surface Emission

Cited by 10 publications

References 29 publications

On the growth mechanism of nanoparticles in plasma during pulsed laser ablation in liquids

On the growth mechanism of nanoparticles in plasma during pulsed laser ablation in liquids

The influence of electron reflection/sticking coefficients at the electrodes on plasma parameters in particle-in-cell simulations of capacitive radio-frequency plasmas

Nucleation and growth of nanoparticles in a plasma by laser ablation in liquid

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