Auger Electron Spectroscopy AES depth profiling

There are several methods available to probe the actual interphase to demonstrate the existence of interpenetrating networks directly. Among these techniques are depth profiling by SIMS (secondary ion mass spectrometry) or SNMS (sputtered neutral mass spectrometry), and the use of X-ray photoelectron spectroscopy (XPS) depth profiling or Auger electron spectroscopy (AES) depth profiling. 

The color-coded nature of the PL in conjunction with Auger electron spectroscopy (AES)/depth profile analysis (which spatially resolves the alloys relative to the surface) permits mapping of the effective electric field (EEF) in the solid the term "effective electric field" reflects the idea that the field has contributions from, for example, band-edge and effective-mass gradients in addition to contributions from band bending (7). 

From the Auger electron spectroscopy (AES) depth profile (Fig. 2), it can be seen that relatively less carbon and a significant amount of oxygen is present at the surface. Furthermore, a higher intensity of iron and an equal amount of silicon compared to the bulk of the film were measured. Compared with XPS observations, it was clear that an Fe-Si xide layer was formed at the exposed surface. The thickness of this oxide layer is approximately lOnm. 

Auger electron spectroscopy (AES) depth profiles of Mg65Cu25Yio sample surfaces recorded after potentiostatic polarization tests in 0.3 M H3B03/Na2B407 buffer solution with pH=8.4 (a) amorphous alloy state (b) crystalline alloy state [59]. 

A new method of interpreting Auger electron spectroscopy (AES) sputter profiles of transition metal carbides and nitrides is proposed. It is shown that the chemical information hidden in the shape of the peaks, and usually neglected in depth profiles, can be successfully extracted by factor analysis (FA). The various carbide and nitride phases of model samples were separated by application of FA to the spectra recorded during AES depth profiles. The different chemical states of carbon, nitrogen and metal were clearly identified. 

Roughness from sputtering causes loss of depth resolution in depth profiling for Auger Electron Spectroscopy (AES), X-Ray Photoelectron Spectroscopy (XPS), and SIMS. 

Fig. 12. Auger electron spectroscopy (AES) sputter-depth profile of CAA-treated titanium after various exposure.s in vacuum (a) as anodized, (b) 450°C for 1 h, and (c) 7(X)°C for 1 h. The sputter etch rate is 1.5 nm/min. The line indicates the original interface. The arrow denotes oxygen diffused into the substrate. Adapted from Ref. [51].

The film thickness and retractive index were calculated using spectroscopic ellipsometry. X-ray photoelectron spectroscopy (XPS) was used for composition analysis. Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) was used to investigate the depth profiles of the film. 

The elemental composition, oxidation state, and coordination environment of species on surfaces can be determined by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) techniques. Both techniques have a penetration depth of 5-20 atomic layers. Especially XPS is commonly used in characterization of electrocatalysts. One common example is the identification and quantification of surface functional groups such as nitrogen species found on carbon-based catalysts.26-29 Secondary Ion Mass spectrometry (SIMS) and Ion Scattering Spectroscopy are alternatives which are more surface sensitive. They can provide information about the surface composition as well as the chemical bonding information from molecular clusters and have been used in characterization of cathode electrodes.30,31 They can also be used for depth profiling purposes. The quantification of the information, however, is rather difficult.32... 

Figure 6.10 Depth profile of Auger Electron Spectroscopy (AES) sputtering of marmatite surface in the presence of cupric ion and ethyl xanthate...

Figure 6. Depth profile of SNR layer by Auger Electron Spectroscopy (AES) (a) no-etching, (b) 1 minute 02 RIE.

Auger electron spectroscopy (AES) is particularly suited for surface analysis (depth 0.5-1 nm). AES depth profile analysis was employed to determine the thickness and composition of surface reaction layers formed under test conditions in the Reichert wear apparatus in the presence of four different ZDDPs additives at different applied loads (Schumacher et al., 1980). Using elemental sensitivity factors the concentration of the four elements (S, P, O, C) was determined at three locations corresponding to a depth of 1.8, 4.3, and 17 nm. No significant correlation between wear behavior and carbon or oxygen content of the reaction layer was observed. A steady state sulfur concentration is reached after a very short friction path. Contrary to the behavior of sulfur, phosphorus concentration in the presence of ZDDPs increases steadily with friction path, and no plateau value is reached. 

The surface of the particles can be studied directly by the use of electron microprobe X-ray emission spectrometry (EMP), electron spectroscopy for chemical analysis (ESCA), Auger electron spectroscopy (AES), and secondary ion-mass spectrometry. Depth-profile analysis determines the variation of chemical composition below the original surface. 

Before discussing these aspects we have to clarify the state of BP on the surface of the positive electrode material. We measured the depth profile of thecobalt positive electrode after 200 cycles by Auger electron spectroscopy (AES), as shown in Fig. 19.18. Thickness of the electroconductive membrane (ECM) film is estimated by the AES depth profiles atomic concentration of cobalt and oxygen. It reaches 90% with and without BP addition as shown in Fig. 19.18. The observed ECM film thicknesses are as follow in the basic electrolyte, the ECM film thickness was 45 A in the functional electrolyte containing 1% of BP, the ECM film thickness was 68 A in the functional electrolyte having 2% of BP, the ECM film thickness was 214 A. These results clearly show that the ECM film thickness on the positive electrode increased with the amount of BP. Based on these results, the cycle life of the basic electrolyte cell should be better, but the cells with the functional electrolyte containing the small amount of BP (the film thickness of 68 A) afford the best results. 

Comparing SIMS and SNMS depth profiles, deviations from the theoretical distribution of, for example, implanted species, are smaller in the case of the SNMS profile (see Figure 40.18). Effects of surface contaminations or oxides on the ionization probability are strong in SIMS, especially in the case of Ar primary ions, as well as the enhancement effect of the oxygen primary ions on the ionization probability. Variations in sputtering rate until a steady state is reached can be corrected in SNMS (see above) so that the SNMS curve corresponds best with the Auger electron spectroscopy (AES) curve [286]. 

FIGURE 40.18 Depth profiles by laser secondary neutral mass spectrometry (laser SNMS), secondary ion mass spectrometry (SIMS) with Ar and 02 primary ions, and Auger electron spectroscopy (AES) of implanted boron. Reprinted from Higashi, Y., Quantitative depth profiling by laser-ionization sputtered neutral mass spectrometry (1999) Spectrochimica Acta Part B Atomic Spectroscopy, 54(1), 109-122. Copyright (1999), with permission from Elsevier Science. 

Mg and possessed a superior corrosion resistance than a couple of Mg alloys and another amorphous alloy Mg65Cu2sYio (Fig. 6.6). Interestingly, the Auger electron spectroscopy (AES) analysis showed that there was no trace of Ga compounds in the passive layer and that it was enriched only with aluminium oxide. However, AES depth profiles suggested the deposition of metallic Ga below the corrosion layer, whieh was further confirmed by the XRD results. It appears that the euhaneed eorrosion resistance was only due to the aluminium oxide enrichment at the surfaee of this alloy. These researeh findings opened up avenues for the development of amorphous alloys with higher aluminium eontent that eould provide not only an improved electrochemical behaviour but superior meehanieal properties as well. 

Secondary ion mass spectrometry (SIMS), secondary neutral mass spectrometry (SNMS), Auger electron spectroscopy (AES) and x-ray photoelectron spectro.scopy (XPS) can provide depth-.selective elemental profiles, but the... 

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