“…The method relies on the fact that the energy distribution of emitted electrons depends on the in-depth concentration profile and is able to differentiate among thin and thick homogeneous overlayers, buried layers, three-dimensional island structures on different substrates, etc. The theoretical framework of the technique is described in detail in the literature [31]. The validity of the technique has been established through systematic experimental investigations and comparison to measurements on the same samples by Rutherford backscattering spectrometry, ion scattering spectrometry, and atomic force microscopy [31][32][33][34].…”