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Collision-spike Sputtering of Au Nanoparticles.

Sandoval L, Urbassek HM - Nanoscale Res Lett (2015)

Bottom Line: While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation.For the particular case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target.The sputter yield of supported nanoparticles is estimated to be around 80 % of that of free nanoparticles due to the suppression of forward sputtering.

View Article: PubMed Central - PubMed

Affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA.

ABSTRACT
Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For the particular case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31 % of the impact energy remains in the nanoparticles after impact; the remainder is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80 % of that of free nanoparticles due to the suppression of forward sputtering.

No MeSH data available.


Related in: MedlinePlus

Snapshots of several events (a-e) at 10 ps after particle impact. Ion impacts at the top at perpendicular incidence angle. Particles are colored according to their kinetic energy from blue (0 eV) to red (≥0.4 eV). Event (e) corresponds to that shown in Fig. 3
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Fig5: Snapshots of several events (a-e) at 10 ps after particle impact. Ion impacts at the top at perpendicular incidence angle. Particles are colored according to their kinetic energy from blue (0 eV) to red (≥0.4 eV). Event (e) corresponds to that shown in Fig. 3

Mentions: We give an impression of the variety of impact events and the sputter emission sites in Fig. 5 which assembles snapshots from different projectile impact points showing the extension of the energy deposition in the NP. The event of Fig. 3 corresponds to Fig. 5a. Fluctuations in energy deposition are strong and so are the ensuing emission profiles. While sometimes only little energy is deposited close to the impact point, Fig. 5c, in other events, energy is deposited both close to the ion impact and at the ion exit point on the NP, Fig. 5a. In most events, a spike is clearly observed in the NP, which is discernible by the high density of particles moving with high energy. We note that kinetic energies above E=0.4 eV correspond to a local temperature of above T=1550 K, assuming E=3kT. The zones delineated in Fig. 5 thus correspond to the molten zones in the NP.Fig. 5


Collision-spike Sputtering of Au Nanoparticles.

Sandoval L, Urbassek HM - Nanoscale Res Lett (2015)

Snapshots of several events (a-e) at 10 ps after particle impact. Ion impacts at the top at perpendicular incidence angle. Particles are colored according to their kinetic energy from blue (0 eV) to red (≥0.4 eV). Event (e) corresponds to that shown in Fig. 3
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4526510&req=5

Fig5: Snapshots of several events (a-e) at 10 ps after particle impact. Ion impacts at the top at perpendicular incidence angle. Particles are colored according to their kinetic energy from blue (0 eV) to red (≥0.4 eV). Event (e) corresponds to that shown in Fig. 3
Mentions: We give an impression of the variety of impact events and the sputter emission sites in Fig. 5 which assembles snapshots from different projectile impact points showing the extension of the energy deposition in the NP. The event of Fig. 3 corresponds to Fig. 5a. Fluctuations in energy deposition are strong and so are the ensuing emission profiles. While sometimes only little energy is deposited close to the impact point, Fig. 5c, in other events, energy is deposited both close to the ion impact and at the ion exit point on the NP, Fig. 5a. In most events, a spike is clearly observed in the NP, which is discernible by the high density of particles moving with high energy. We note that kinetic energies above E=0.4 eV correspond to a local temperature of above T=1550 K, assuming E=3kT. The zones delineated in Fig. 5 thus correspond to the molten zones in the NP.Fig. 5

Bottom Line: While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation.For the particular case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target.The sputter yield of supported nanoparticles is estimated to be around 80 % of that of free nanoparticles due to the suppression of forward sputtering.

View Article: PubMed Central - PubMed

Affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA.

ABSTRACT
Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For the particular case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31 % of the impact energy remains in the nanoparticles after impact; the remainder is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80 % of that of free nanoparticles due to the suppression of forward sputtering.

No MeSH data available.


Related in: MedlinePlus