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Auger peaks

The results shown in Figure 6 above are an example of this mode of analysis, but include additional information on the chemical states of the Si. The third most frequently used mode of analysis is the Auger mapping mode, in which an Auger peak of a particular element is monitored while the primary electron beam is raster scanned over an area. This mode determines the spatial distribution, across the surface, of the element of interest, rather than in depth, as depth profiling does. Of course, the second and third modes can be combined to produce a three-dimensional spatial distribution of the element. The fourth operational mode is just a subset of the third mode a line scan of the primary beam is done across a region of interest, instead of rastering over an area. [Pg.322]

Figure 3 First-derivative electron emission spectra from pure lanthanum taken with primary electron beams having energies of 250 and 235 eV showing the unshifted Auger peaks and the shifted REELS peaks. Figure 3 First-derivative electron emission spectra from pure lanthanum taken with primary electron beams having energies of 250 and 235 eV showing the unshifted Auger peaks and the shifted REELS peaks.
Section 2.1.3 shows that in an XPS spectrum. X-ray excited Auger peaks are often as prominent as the photoelectron peaks themselves. For many elements, the chemical shifts in Auger peaks are actually greater than the shifts in photoelectron peaks. The two shifts can be combined in a very useful quantity called the Auger parameter a, first used by Wagner [2.30] and defined in its modified form [2.31] as... [Pg.22]

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. [Pg.36]

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. [Pg.519]

Figure 4.8. XPS wide-scan spectrum of a Rh/AIjO, model catalyst prepared by impregnating AI2O3 with a solution of RhClj in water. The photoelectron and Auger peaks (left) are given, along with a region of interest from the Rh 3d spectrum of the fresh and the... Figure 4.8. XPS wide-scan spectrum of a Rh/AIjO, model catalyst prepared by impregnating AI2O3 with a solution of RhClj in water. The photoelectron and Auger peaks (left) are given, along with a region of interest from the Rh 3d spectrum of the fresh and the...
The relative product yields depend on the CHa to Cl ratio on the surface. In the studies reported here, this ratio has been adjusted to 1 1 (consistent with the CHa Cl stoichiometry in CHaCl) on the basis of a Cl(181 eV) C(272 eV) Auger peak ratio of 6.5 which is the same as that measured for physisorbed monolayers of dimethyldichlorosilane. Monolayer coverages of CHa + Cl having 1 1 stoichiometry were obtained by a 20 L exposure from the methyl radical source (approximately sahiration coverage) followed by a 9.5 L dose of CI2. [Pg.309]

In all of the studies described above, the CuaSi samples were prepared by ion bombardment at 330 K followed by cooling of the surface to 180 K before adsorbing the methyl radicals and chlorine. AES studies as well as ion scattering results in the literature [7, 15] show that this procedure produces a surface that is enriched in silicon compared with the Cu3Si bulk stoicWometry. We have found that surfaces with less Si enrichment (possibly even copper enriched relative to the bulk stoichiometry) can be prepared by ion bombardment at temperatures below 300 K. Specifically, Cu(60 eV)/Si(92 eV) Auger peak ratios of 1.2 - 1.7 compared with a ratio of 0.5 at 400 K can be obteiined by sputtering at 180 K. [Pg.312]

The Auger peaks are superimposed on a large background of other scattered electrons. A CMA can filter these spurious electrons and allow the Auger electrons to reach the detector. The results are usually plotted as a derivative spectrum. [Pg.510]

The identification of the major peaks in the spectrum is accomplished by comparison with reference data (e.g. Wagner et al. 1978). The qualitative analysis of XPS spectra is more complex than for AES due to the presence of Auger peaks in addition to photoelectron peaks. If a photoelectron line of one element is close in energy to an Auger line of another, the problem may be resolved by taking spectra at two different photon energies. [Pg.28]

The total contribution to the Auger electron signal is then dependent upon the attenuation length (kM) in the matrix before being inelastically scattered, and upon the transmission efficiency of the electron spectrometer as well as the efficiency of the electron detector. Calculated intensities of Auger peaks rarely give an accuracy better than 50%, and it is more reliable to adopt an approach which utilises standards, preferably obtained in the same instrument. [Pg.175]

Figure 5.34. (a) Shows the relation between Auger peak height ratio (P/Fe) and the crystallographic... [Pg.181]

The shape and energy of the resulting Auger peaks are thus useful in identifying the elemental composition of the sample surface as well as obtaining useful chemical information. [Pg.396]


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Auger

Auger peak position

Energy of Auger Peaks

Intensity of Auger Peaks

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