Dielectric loss function of Si and SiO₂ from quantitative analysis of REELS spectra

Abstract

A recently proposed model for quantitative analysis of reflection electron energy-lass spectra (REELS) has been applied to evaluate the dielectric loss function of Si and SiO, in the 4-100 eV energy range, and to determine inelastic scattering properties for these materials for low-energy electrons (5Oo--10 OOO eV). Appropriate trial energy-loss functions (i.e. Im{l/c}) are used and the best loss function is found from the criterion that a satisfactory quantitative agreement is obtained between the simulated and experimental inelastic scattering cross-sections at several primary electron energies. The fact that the energy-loss functions determined in this work agree remarkably well with optical data gives some confidence in the applied procedure. In addition, the effective inelastic mean free paths of the electrons as a function of the primary energy and the path travelled inside the medium have also been determined in terms of the respective energy-loss functions.

Surface excitation parameter for 12 semiconductors and determination of a general predictive formula

“…1. Finally for Si, we used data from Yubero et al [44] in which parameters are obtained by fitting the differential inelastic electron scattering cross-section spectrum simulated with QUEELS to an experimental inelastic scattering cross-section. At last, we have adjusted all the oscillator strengths to fulfill the optical sum rule.…”

Variation of the electron inelastic mean free path during depth profiling of the Fe/Si interface as determined by quantitative REELS

“…Figure 1(b)), the main peak is observed at 16.8 eV in good agreement with published data for the bulk plasmon, whereas a broad shoulder at energies below 15 eV appears to be associated with excitation of the surface plasmon and surface transitions. 14,25 Figure 1 also includes the respective theoretical inelastic scattering cross-sections K th (dotted curve) calculated according to the procedure developed by Tougaard et al,12 with rather good agreement seen between K th and K exp for the three different primary energies, considering that the comparison is performed on an absolute scale.…”

Valley-dependent Carrier and Lattice Dynamics in Silicon measured by Transient XUV Spectroscopy

“…The changes in the differential XUV absorption with optical excitation results from three sources. First, excitation of carriers from the valence to conduction band changes the electron loss function, broadening the excited state spectrum [2]. Second, state-filling effects from the photoexcited carriers lead to an increased absorption for holes in the valence band and a decreased absorption for electrons in the conduction band [3].…”

“…The background component is modeled by inspection of the remaining critical points in the band structure. Broadening is included to the critical point density of states using a single-plasmon pole model with the plasmon frequency at16.8 eV, corresponding to the valence carrier density of Si [2]. The 100 meV instrumental resolution is further included by a Gaussian broadening.…”