Analysis of the principal components for REEL spectra of indium

Abstract

The reflection electron energy loss (REEL) spectra of indium for 300 eV energy of the primary electrons are analyzed with change of the experimental geometry conditions. It is demonstrated that the principal component analysis allows to describe the spectra as linear combinations of the three principal components within the range of scattering angles 94–146°. It is shown that the shapes of surface and volume plasmon peaks do not change with change of the geometric conditions of the experiment. At the same time, the electron scattering angle considerably and differently influences the relative intensity of the surface and volume plasmon peaks. Intensity of the volume plasmon peak (normalized by intensity of the peak of the elastically reflected electrons) changes almost three times in the magnitude. This considerably exceeds possible changes of the intensity due to changes of the angle of primary electron incidence and exit angle for the detected electrons.