Measured reflection electron energy loss spectra excited by 2 keV electrons in Si are simulated by a Monte Carlo approach using the Chen–Kwei theory to calculate the position-dependent inverse inelastic mean free path. By comparing measured and calculated spectra, several prescriptions concerning the momentum transfer dependence of the material dielectric function are discussed. Our results lend support to the approximation (often taken with the only justification of making relations simpler) of neglecting the momentum transfer component normal to the surface in the surface region.
Date of publication:
Surf. Interface Anal. 46 (2014) 340