Depth of Origin of Secondary Ions: Suppression and Enhancement of Ions Upon Passage Through Overlayers.

1994 ◽  
Vol 354 ◽  
Author(s):  
N. J. Sack ◽  
M. Akbulut ◽  
T. E. Madey
Keyword(s):  
Solid Surfaces ◽  
Rare Gas ◽  
Rare Gases ◽  
Secondary Ions ◽  
Vacuum Interface ◽  
Rare Gas Atoms ◽  
Electron Stimulated Desorption ◽  
Energy And Angular Distributions ◽  
The Impact ◽  
Low Energy Ions

AbstractWe are investigating the transmission of low energy ions (<10 eV) through ultrathin films of condensed rare gases. Our goal is to address the issue of the depth of origin of secondary ions that desorb from solid surfaces under the impact of ionizing radiation, such as electrons, photons, or through ion sputtering. The secondary ions are produced by electron stimulated desorption (ESD) from a suitable substrate, such as an oxide or an adsórbate on a metal single crystal; the overlayer gas is condensed onto this substrate. The yield, energy and angular distributions of the ions are measured as a function of overlayer thickness. We find that 7 eV oxygen ions can be transmitted through rare gas films (Kr, Xe) several ML thick. In contrast, O+ is completely suppressed by 0.5 ML of H2O. Surprisingly, we find the F− yield to be 4 times higher in the presence of 1 ML of Xe, compared to the clean surface value, accompanied by a dramatic change in the ions’ angular distribution. We discuss a model which considers elastic scattering and charge transfer of the ions with rare gas atoms, as well as the structure of the surface and the electronic properties of the solid-vacuum interface.

Scattering of metastable rare gas atoms from solid surfaces

1982 ◽  
Vol 117 (1-3) ◽  
pp. A194
Author(s):  
H. Conrad ◽  
G. Ertl ◽  
J. Küppers ◽  
W. Sesselmann ◽  
B. Woratschek ◽  
...  
Keyword(s):  
Solid Surfaces ◽  
Rare Gas ◽  
Rare Gas Atoms

Bonding of Rare-Gas Atoms to Si in Reactions of Rare Gases with SiF3+

2001 ◽  
Vol 105 (49) ◽  
pp. 11073-11079 ◽  
Author(s):  
A. Cunje ◽  
V. I. Baranov ◽  
Y. Ling ◽  
A. C. Hopkinson ◽  
D. K. Bohme
Keyword(s):  
Rare Gas ◽  
Rare Gases ◽  
Rare Gas Atoms

The Influence Of Matter And Black-Body Radiation Photons On The Dipole Polarizabilities A And γ Of Atoms

1996 ◽  
Vol 51 (7) ◽  
pp. 805-808 ◽  
Author(s):  
Uwe Hohm
Keyword(s):  
Reaction Rate ◽  
Black Body ◽  
Black Body Radiation ◽  
Rare Gas ◽  
Dipole Polarizability ◽  
Rare Gases ◽  
Reaction Rate Constants ◽  
Molecule Reaction ◽  
Rare Gas Atoms ◽  
Linear Dipole

Abstract The influence of the surroundings on the linear dipole polarizability α and second hyperpo-larizability γ is discussed in terms of the density ϱM of isotropically distributed matter as well as the density ϱp of thermal black-body radiation photons, α and γ of the rare gas atoms are studied as examples. At standard conditions, both effects are of comparable size for the rare gases. Possible consequences for ion-molecule reaction rate constants in astronomical environments are suggested.

Electron loss cross sections from rare gas atoms to Ar+

1982 ◽  
Vol 60 (7) ◽  
pp. 977-980
Author(s):  
B. Hird ◽  
S. P. Ali
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Energy Region ◽  
Rare Gas ◽  
Electron Loss ◽  
Rare Gases ◽  
Thin Target ◽  
Rare Gas Atoms ◽  
Good Agreement

Measurements of the σ10 cross section for a beam of Ar+ ions of energies between 30 and 120 keV passing through a thin target of the rare gases show good agreement with the few previous measurements in this energy region.

Microstructure Characterization of Hydrogenated Amorphous Silicon Films by Rare Gas Effusion Studies

2001 ◽  
Vol 664 ◽  
Author(s):  
Wolfhard Beyer
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Films ◽  
Rare Gas ◽  
Rare Gases ◽  
Boron Doped ◽  
Rare Gas Atoms ◽  
Hydrogenated Amorphous ◽  
Substrate Temperatures

ABSTRACTThe effusion of the rare gases neon and helium, as well as of hydrogen, was studied for plasma deposited (boron-doped and undoped) hydrogenated amorphous silicon films, grown at various substrate temperatures. Rare gas atoms were incorporated into the material during the growth process or by ion implantation. The results suggest that helium and neon effusion spectra give information on the material microstructure.

Studies of Energy Transfer and Ionization Processes in a Helium ICP

1987 ◽  
Vol 41 (4) ◽  
pp. 621-624 ◽  
Author(s):  
H. B. Fannin ◽  
C. J. Seliskar ◽  
D. C. Miller
Keyword(s):  
Population Distribution ◽  
Rare Gas ◽  
Rare Gases ◽  
Reduced Pressure ◽  
Plasma Energy ◽  
Neutral Gas ◽  
Positive Ions ◽  
Population Distributions ◽  
Rare Gas Atoms ◽  
Ionization Behavior

The spectral consequences of the introduction of varying concentrations of heavy rare gas atoms into a reduced-pressure helium ICP have been examined. A term-dependent quenching of He(I) emission was observed and is consistent with previous work on a kinetic model for this ICP. In addition, the ionization behavior of the added rare gases has been studied, and a simple rule seems to emerge from the results: the first ionization potential of helium represents an upper bound to the plasma energy available (probably through collisional processes) to excite and/or ionize added species. Although spectroscopic temperatures can be calculated from the state population distributions for the added neutral gas atoms, the fact that the values vary with concentration and with the chemical identity of the species betrays the fact that the plasma is not in local thermodynamic equilibrium with respect to neutral atoms. Quite differently, the results for plasma positive ions show the same statistically determined spectroscopic temperatures; thus, it appears that these ions are nearly equilibrated and also suprathermal in population distribution.

scholarly journals Experimental and simulation-based investigation of He, Ne and Ar irradiation of polymers for ion microscopy

2016 ◽  
Vol 7 ◽  
pp. 1113-1128 ◽  
Author(s):  
Lukasz Rzeznik ◽  
Yves Fleming ◽  
Tom Wirtz ◽  
Patrick Philipp
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Bubble Formation ◽  
Md Simulations ◽  
Rare Gas ◽  
Preferential Sputtering ◽  
Rare Gas Atoms ◽  
Impact Energies ◽  
Primary Ions ◽  
The Impact ◽  
Ion Species

Secondary ion mass spectrometry (SIMS) on the helium ion microscope (HIM) promises higher lateral resolution than on classical SIMS instruments. However, full advantage of this new technique can only be obtained when the interaction of He+ or Ne+ primary ions with the sample is fully controlled. In this work we investigate how He+ and Ne+ bombardment influences roughness formation and preferential sputtering for polymer samples and how they compare to Ar+ primary ions used in classical SIMS by combining experimental techniques with Molecular Dynamics (MD) simulations and SD_TRIM_SP modelling. The results show that diffusion coefficients for He, Ne and Ar in polymers are sufficiently high to prevent any accumulation of rare gas atoms in the polymers which could lead to some swelling and bubble formation. Roughness formation was also not observed. Preferential sputtering is more of a problem, with enrichment of carbon up to surface concentrations above 80%. In general, the preferential sputtering is largely depending on the primary ion species and the impact energies. For He+ bombardment, it is more of an issue for low keV impact energies and for the heavier primary ion species the preferential sputtering is sample dependent. For He+ steady state conditions are reached for fluences much higher than 1018 ions/cm2. For Ne+ and Ar+, the transient regime extends up to fluences of 1017–1018 ions/cm2. Hence, preferential sputtering needs to be taken into account when interpreting images recorded under He+ or Ne+ bombardment on the HIM.

Scattering of metastable rare gas atoms from solid surfaces

1982 ◽  
Vol 117 (1-3) ◽  
pp. 98-108 ◽  
Author(s):  
H. Conrad ◽  
G. Ertl ◽  
J. Küppers ◽  
W. Sesselmann ◽  
B. Woratschek ◽  
...  
Keyword(s):  
Solid Surfaces ◽  
Rare Gas ◽  
Rare Gas Atoms
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