Ag polycrystal and monocrystal by high sensitivity-low energy ion scattering

Abstract

Low energy ion scattering is a qualitative and quantitative surface analysis technique. Its supreme surface sensitivity and straightforward quantification (using a well-defined reference) make it a convenient tool for the study of surface composition and a useful method for surface characterization in cooperation with other surface analysis methods such as XPS and SIMS. Silver (100) monocrystal was analyzed by the primary beam of helium ions. The wide energy range from 1.0 to 4.5 keV covers three distinguished regions. On the low energy side, the charge exchange processes are dominated by Auger neutralization (AN), while collision-induced (CI) processes rule a high energy range. Both mechanisms are mixed in the intermediate region between 1.2 and 2.1 keV (for perpendicular incidence and 145 degrees scattering geometry). The results can serve both as a reference and as an insight into neutralization probability changes (as dependence on primary energy). The neutralization strength is reflected by the characteristic velocity. It was evaluated for AN and CI regions to 0.75 x 105 and 0.38 x 105 ms-1, respectively. The CI reionization energy threshold is around 1700 eV for both Ag (100) and polycrystalline Ag. The reference measurement on polycrystalline copper relates the presented data to those received by other Qtac100 instruments with different sensitivities.

Low energy ion scattering is a qualitative and quantitative surface analysis technique. Its supreme surface sensitivity and straightforward quantification (using a well-defined reference) make it a convenient tool for the study of surface composition and a useful method for surface characterization in cooperation with other surface analysis methods such as XPS and SIMS. Silver (100) monocrystal was analyzed by the primary beam of helium ions. The wide energy range from 1.0 to 4.5 keV covers three distinguished regions. On the low energy side, the charge exchange processes are dominated by Auger neutralization (AN), while collision-induced (CI) processes rule a high energy range. Both mechanisms are mixed in the intermediate region between 1.2 and 2.1 keV (for perpendicular incidence and 145 degrees scattering geometry). The results can serve both as a reference and as an insight into neutralization probability changes (as dependence on primary energy). The neutralization strength is reflected by the characteristic velocity. It was evaluated for AN and CI regions to 0.75 x 105 and 0.38 x 105 ms-1, respectively. The CI reionization energy threshold is around 1700 eV for both Ag (100) and polycrystalline Ag. The reference measurement on polycrystalline copper relates the presented data to those received by other Qtac100 instruments with different sensitivities.