Enhancement of Sputtering Yields Due to C<sub>60</sub> versus Ga Bombardment of Ag{111} As Explored by Molecular Dynamics Simulations

Postawa, Zbigniew; Czerwinski, Bartlomiej; Szewczyk, Marek; Smiley, Edward J.; Winograd, Nicholas; Garrison, Barbara J.

doi:10.1021/ac034387a

Cited by 190 publications

(222 citation statements)

References 39 publications

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“…This is particularly true for the impact energy dependence observed under C 60 bombardment, where the experiment detects almost identical°ratios°as°predicted°from°the°simulations° [22]. Comparing the absolute yield values, we find the experimental C 60 data to be about a factor of 3 lower than predicted, whereas the value measured for Ga is almost exactly reproduced by the simulation.…”

Section: Total Yieldsupporting

confidence: 54%

“…More specifically, the respective peaks in the TOF mass spectra are integrated over the entire isotopic abundance pattern, normalized to the primary ion current, and the ratio between the data obtained from C 60 ϩ and Ga ϩ bombardment is calculated as an enhancement°factor.°The°results°are°listed°in°Table°2°for 10, 15, and 20 keV impact energy. For comparison, the respective°data°obtained°from°the°MD°simulations° [22] are also presented. As can be seen from the table, we find a qualitative agreement between the measured data and the prediction from the simulations.…”

Section: Partial Yieldsmentioning

confidence: 99%

“…The spike model has traditionally been employed to interpret the response of metallic targets to cluster bombardment [20]. Instead, the emission mechanism is proposed to involve the quasi-free expansion of a super-critically heated subsurface volume.Recent molecular dynamics (MD) computer simulations show a largely different desorption process for isoenergetic Ga and C 60 bombardment [21,22]. For 15 keV Ga bombardment of Ag{111}, atomic motion is described by a classic collision cascade with a desorption yield of about 20 Ag atoms per incident Ga ϩ ion.…”

mentioning

confidence: 99%

“…Recent molecular dynamics (MD) computer simulations show a largely different desorption process for isoenergetic Ga and C 60 bombardment [21,22]. For 15 keV Ga bombardment of Ag{111}, atomic motion is described by a classic collision cascade with a desorption yield of about 20 Ag atoms per incident Ga ϩ ion.…”

mentioning

confidence: 99%

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Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles

Sun

Szakal

Winograd

et al. 2005

J. Am. Soc. Mass Spectrom.

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The ion bombardment-induced release of particles from a metal surface is investigated using energetic fullerene cluster ions as projectiles. The total sputter yield as well as partial yields of neutral and charged monomers and clusters leaving the surface are measured and compared with corresponding data obtained with atomic projectile ions of similar impact kinetic energy. It is found that all yields are enhanced by about one order of magnitude under bombardment with the C 60 ϩ cluster projectiles compared with Ga ϩ ions. In contrast, the electronic excitation processes determining the secondary ion formation probability are unaffected. The kinetic energy spectra of sputtered particles exhibit characteristic differences which reflect the largely different nature of the sputtering process for both types of projectiles. In particular, it is found that under C 60 ϩ impact (1) the energy spectrum of sputtered atoms peaks at significantly lower kinetic energies than for Ga ϩ bombardment and (2) the velocity spectra of monomers and dimers are virtually identical, a finding which is in pronounced contrast to all published data obtained for atomic projectiles. T he elucidation of the mechanism of interaction of energetic polyatomic or cluster ions with surfaces is of current interest since these projectiles are now being extensively employed as desorption probes in secondary ion mass spectrometry (SIMS) experiments [1,2]. Because of their propensity to produce higher molecular ion signals than corresponding atomic ions and the emergence of commercially available C 60 ϩ [3,4] and Au 3 ϩ [5, 6] ion guns, applications have expanded dramatically. For example, these sources can be focused onto the sample with a probe size about 1 micron, allowing greatly improved molecule-specific imaging experiments. The high secondary ion yield associated with the cluster/solid interaction also allows for molecular depth profiling studies without the accompanying damage accumulation normally associated with atomic bombardment [7][8][9][10][11][12][13][14][15][16][17].The mechanisms associated with the observed secondary ion yield enhancement are not yet clear, although details are emerging quickly. A basic question that must be resolved is to determine whether the yield enhancement occurs as a consequence of increased ionization efficiency, or is due to more effective sputtering in the neutral desorption channel. There is mixed information about this point. For In and Ag surfaces, for example, it has been shown that the enhanced secondary ion yield under SF m ϩ bombardment (m ϭ 1-5) largely arises from the enhanced ionization efficiency attributable to implanted F atoms [18]. For organic systems, however, very high removal rates of neutral species have been reported [2], obviating the need to invoke enhancement of the secondary ionization probability. Most recently, yields and velocity distributions were measured for In and In 2 sputtered from In surfaces bombarded with Au ϩ , Au 2 ϩ , and Au 3 ϩ [19]. Although these experiments do not ad...

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Section: Total Yieldsupporting

confidence: 54%

Section: Partial Yieldsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles

Sun

Szakal

Winograd

et al. 2005

J. Am. Soc. Mass Spectrom.

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“…It has been demonstrated that these enhanced yields are produced with a concomitant increase in surface damage, but the yield enhancement surpasses that of damage [32]. Many studies have combined to develop the now accepted idea that the lower penetration depth and overlapping collision cascades of the polyatomic primary ion deposit more energy in the surface region, thus leading to increased sputtering [33][34][35][36][37][38][39].…”

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confidence: 99%

Higher sensitivity secondary ion mass spectrometry of biological molecules for high resolution, chemically specific imaging

McDonnell

Heeren

Lange

et al. 2006

J. Am. Soc. Mass Spectrom.

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To expand the role of high spatial resolution secondary ion mass spectrometry (SIMS) in biological studies, numerous developments have been reported in recent years for enhancing the molecular ion yield of high mass molecules. These include both surface modification, including matrix-enhanced SIMS and metal-assisted SIMS, and polyatomic primary ions. Using rat brain tissue sections and a bismuth primary ion gun able to produce atomic and polyatomic primary ions, we report here how the sensitivity enhancements provided by these developments are additive. Combined surface modification and polyatomic primary ions provided Ϸ15.8 times more signal than using atomic primary ions on the raw sample, whereas surface modification and polyatomic primary ions yield Ϸ3.8 and Ϸ8.4 times more signal. This higher sensitivity is used to generate chemically specific images of higher mass biomolecules using a single molecular ion

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TOF‐SIMS Applications to Bioimaging and Biomolecule Evaluation Methods

Aoyagi

2012

Mass Spectrometry Handbook

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Enhancement of Sputtering Yields Due to C₆₀ versus Ga Bombardment of Ag{111} As Explored by Molecular Dynamics Simulations

Cited by 190 publications

References 39 publications

Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles

Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles

Higher sensitivity secondary ion mass spectrometry of biological molecules for high resolution, chemically specific imaging

TOF‐SIMS Applications to Bioimaging and Biomolecule Evaluation Methods

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Enhancement of Sputtering Yields Due to C60 versus Ga Bombardment of Ag{111} As Explored by Molecular Dynamics Simulations

Cited by 190 publications

References 39 publications

Energetic ion bombardment of Ag surfaces by C60+ and Ga+ projectiles

Energetic ion bombardment of Ag surfaces by C60+ and Ga+ projectiles

Higher sensitivity secondary ion mass spectrometry of biological molecules for high resolution, chemically specific imaging

TOF‐SIMS Applications to Bioimaging and Biomolecule Evaluation Methods

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Enhancement of Sputtering Yields Due to C₆₀ versus Ga Bombardment of Ag{111} As Explored by Molecular Dynamics Simulations

Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles

Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles