Auger electron spectroscopy oxidized

Surface analysis has made enormous contributions to the field of adhesion science. It enabled investigators to probe fundamental aspects of adhesion such as the composition of anodic oxides on metals, the surface composition of polymers that have been pretreated by etching, the nature of reactions occurring at the interface between a primer and a substrate or between a primer and an adhesive, and the orientation of molecules adsorbed onto substrates. Surface analysis has also enabled adhesion scientists to determine the mechanisms responsible for failure of adhesive bonds, especially after exposure to aggressive environments. The objective of this chapter is to review the principals of surface analysis techniques including attenuated total reflection (ATR) and reflection-absorption (RAIR) infrared spectroscopy. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and secondary ion mass spectrometry (SIMS) and to present examples of the application of each technique to important problems in adhesion science. 

We have undertaken a series of experiments Involving thin film models of such powdered transition metal catalysts (13,14). In this paper we present a brief review of the results we have obtained to date Involving platinum and rhodium deposited on thin films of tltanla, the latter prepared by oxidation of a tltanliua single crystal. These systems are prepared and characterized under well-controlled conditions. We have used thermal desorption spectroscopy (TDS), Auger electron spectroscopy (AES) and static secondary Ion mass spectrometry (SSIMS). Our results Illustrate the power of SSIMS In understanding the processes that take place during thermal treatment of these thin films. Thermal desorption spectroscopy Is used to characterize the adsorption and desorption of small molecules, In particular, carbon monoxide. AES confirms the SSIMS results and was used to verify the surface cleanliness of the films as they were prepared. 

Jerkiewicz G, Vatankhah G, Lessard J, Soriaga MP, Park YS. 2004. Surface-oxide growth at platinum electrodes in aqueous H2SO4 Reexamination of its mecharusm through combined cyclic-voltammetry, electrochemical quartz-crystal nanobalance, and Auger electron spectroscopy measurements. Electrochim Acta 49 1451-1459. 

Auger electron spectroscopy is preferred over XPS where high spatial resolution is required, although the samples need to be conducting and tolerant to damage from the electron beam. Many oxides readily decompose under electron radiation, and this may give rise to difficulty in spectral interpretation, and this has restricted the application of AES in the field of catalysis. 

Pedraza, A. M. Villegas, I. Freund, P. L. Chornik, B. Electro oxidation of thiosulfate ion on gold. Study by means of cyclic voltammetry and Auger electron spectroscopy. J Electroanal. Chem. Inter. Electrochem. 1988, 250, 443 149. 

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 10.13 (A) HREEL and (B) Auger electron spectroscopy (AES) spectra for 1.5 monolayer (ML) TO on the Si02(ML)/Mo(112) surface following annealing at various temperatures (a) Si02(ML)/Mo(112), (b) oxidized at 600 K, (c) oxidized at 800 K, (d) annealed at 1200 K, (e) annealed at 1400 K, and (f) 1 ML Ti oxidized at 800 K. (From Chen, M.-S. et al., Surf. Sci., 581, L115-L121,2005. Used with permission from Elsevier Scientific Publishers.)...

Quantitative Auger electron spectroscopy depth profiling of iron oxides formed on Fe (100) and polycrystalline Fe by exposure to gas phase oxygen and borate buffer solution. Langmuir 6 1683-1690... 

Sorenson etal. [449] have carried out similar studies on electrodeposition of atomic Te layers on Au(lll) surfaces from aqueous solutions. Similarly as in earher works, in this study also, the following techniques were utilized voltammetry, in situ STM, low-energy electron diffraction, and Auger electron spectroscopy. Prior to the deposition, tellurium oxide species coated the surface. Two steps were distinguished in the UPD process. Deposition process was Idnetically slow. 

The performance of the V-Mg oxide catalyst was found to depend on its composition and the method of preparation. As to the composition, it was found that catalysts containing very small or very large amounts of vanadium were not selective. The better catalysts in terms of both activity and selectivity consisted of from about 10 to 60 wt% V2O5 (35). Analyses of these catalysts by X-ray diffraction, Auger electron spectroscopy, and infrared spectroscopy showed that they contained only two identifiable phases Mg orthovanadate (Mg3(V04)2) and MgO. Since MgO had low activity and poor selectivity under the reaction conditions employed, it was concluded that the active phase was Mg orthovanadate (Mg3(V04)2). Indeed, it was later shown that this compound was a selective catalyst (26). 

---