Experimental determination of electron inelastic mean free paths in 13 elemental solids in the 50 to 5000 eV energy range by elastic‐peak electron spectroscopy

Abstract

We have determined electron inelastic mean free paths (IMFPs) in C (graphite), Si, Cr, Fe, Cu, Zn, Ga, Mo, Ag, Ta, W, Pt and Au by elastic-peak electron spectroscopy (EPES) using Ni as a reference material for electron energies between 50 and 5000 eV. These IMFPs could be fitted by the simple Bethe equation for inelastic electron scattering in matter for energies from 100 to 5000 eV. The average root-mean-square (RMS) deviation in these fits was 9%. The IMFPs for Si, Cr, Fe, Cu, Ag, Ta, W, Pt and Au were in excellent agreement with the corresponding values calculated from optical data for energies between 100 and 5000 eV. While the RMS differences for graphite and Mo in these comparisons were large (27 and 17%, respectively), the average RMS difference for the other 11 elements was 11%. Similar comparisons were made between our IMFPs and values obtained from the TPP-2M predictive equation for energies between 100 and 5000 eV, and the average RMS difference for the 13 solids was 10.7%; in these comparisons, the RMS differences for Ta and W were relatively large (26% for each). A correction for surface-electronic excitations was calculated from a formula of Werner et al.; except for Si and Ga, the average correction was 5% for energies between 150 and 5000 eV. The satisfactory consistency between the IMFPs from our EPES experiments and the corresponding IMFPs computed from optical data indicates that the uncertainty of these IMFPs is about 11% for electron energies between 100 and 5000 eV. Similar comparisons with IMFPs from the EPES experiments of Werner et al. showed a consistency of 8% for energies between 200 and 5000 eV.

Band bending and alignment at the spinel/perovskiteγ−Al2O3/SrTiO3heterointerface

“…The ratio between bulk and bending zone intensity is determined by the effective inelastic mean-free path λ eff = λ IMFP cos θ , which implicitly includes the angle of emission θ and the inelastic mean-free path λ IMFP . While θ is known from experiment, λ IMFP is obtained from the TPP2 relation applied to STO [36]. Note that the γ -Al 2 O 3 overlayer only leads to an overall damping of the entire signal and hence does not influence the line shape.…”

Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag–Au/polytetrafluoroethylene nanocomposites

“…Figure 5a, b shows changes in the morphology and in the surface amount of the 5.5 nm alloy NPs of 70 % Ag-30 % Au before and after immersion in water. The nanoparticles density looks smaller after 3 days in water, and the interparticle distance increases as a result of the reduction of the Ag [31] fraction due to Ag ion release which is more favorable from the smaller particles. Additionally, other NPs may undergo Ostwald ripening process, i.e., growth of large particles by dissolution of small particles driven by the particle size dependence of its standard electrode potential, in a way similar to what we observed before for pure AgNPs [15,16].…”

Temporal broadening of attosecond photoelectron wavepackets from solid surfaces

“…For a mean free path comparable to the XUV photon penetration depth, the streaking trace would become heavily smeared in the time direction [16]. For 84 eV photoelectrons (the typical photoelectron energy in our experiments) the mean free paths in gold and WO 3 are ∼ 0.39 nm and ∼ 0.49 nm, respectively, calculated using the Tanuma, Powell and Penn (TPP-2M) formula [17], with parameters for the calculation taken from [14,18]. Over these mean free paths the expected temporal broadening is 72 asec for gold and 90 asec for WO 3 .…”