Auger peak position

Table 1.1 Auger peak positions of lithium in the literature...

The principal use of Auger spectroscopy is in the determination of surface composition, although peak positions are secondarily sensitive to the valence state of the atom. See Refs. 2, 82, and 83 for reviews. 

Note from Fig. 2.20 that although the true position of the boron KLL Auger peak in the N(E) spectrum is at 167 eV, the position in the dN(E)/dE spectrum is taken for purely conventional reasons to be that of the negative minimum, i.e. at 175 eV. 

In the majority of spectrometers, A1 and Mg are commonly used as x-ray target materials. With two anodes, A1 and Mg, it is possible to resolve overlapping photoelectron and Auger electron peaks. This is because in an XPS spectrum the position of the Auger peaks changes if Al radiation is replaced by Mg K radiation, but the positions of the photoelectron peaks are unaltered. 

The position of a nickel Auger peak superimposed on the N(ls) photoelectron peak was detected when spectra of coated nickel samples were collected on the Physical Electronics Model 5300 ESCA system using Mg Ka X-rays. Therefore, XPS spectra of nickel samples were obtained using a Surface Science Instruments SSX-100-03 instrument equipped with a monochromatic A1 Ka source. The N(ls) high-resolution spectra obtained from polished nickel which had been coated with y-APS from a 1% aqueous solution at pH 10.4 are shown in Fig. 8. 

Figure 5.2 Spectrum of a sodium deposit on Teflon showing the symmetrical positions of photopeaks and Auger peaks.

Fig. 8.1 Lejt) LEED pattern taken at 155 eV of a thick (-9 monolayers) Pd film evaporated on TiO lllO). Right) Auger spectra recorded on (a) reduced TiOjCllO), (b) as-grown Pd film on TiO lllO), (c) Pd film after annealing at 573 K for 25 min, (d) expanded version of (c) with the Pd peak multiphed by a factor of 1.5 and O region multiphed by a factor of 10 and (e) after annealing at 873 K for 30 min. Peak positions are marked with an underscore. The Mo peaks are from the STM sample holder. Reprinted with permission from [19]. Copyright (2008) Elsevier...

Figure 7.17 Comparison of positions and shapes of OKLL Auger peaks in several solid oxides. (Reproduced with permission from D. Briggs and M.P. Seah, Practical Surface Analysis, Volume 1, John Wiley Sons Ltd, Chichester. 1990 John Wiley Sons Ltd.)...

The assignment of the peaks, which, as described above, may be XPS transitions or their associated Auger peaks, is accomplished with the aid of a handbook or computer database of peak positions. All elements of the periodic table, with the exception of hydrogen, can be detected and XPS is able to analyze light elements with ease, a feature that makes it particularly attractive for the analysis of organic polymers. Minor X-ray satellites will be present if an achromatic X-ray source has been employed and arise from photoelectron transitions excited by the minor components (Kc(3,4 and K ) of such X-radiation. In Figure 2, the major photoelectron peaks (fluorine 1 s and carbon 1 s) are a result of A1 Kcd 2 induced photoemission. Features labeled Ka3 4 and arise from fluorine 1 s electrons ejected by the A1 Ka3,4 and A1 components of the radiation, respectively. Instruments are often equipped with a monochromator that remove the Kc(3 4 and satellite lines from the beam of X-rays. 

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