XPS profiles

The diffusion coefficients in Table II can be compared with penetration depths measured by XPS profiling through the relationship (9),... 

A surface peak effect has been observed during Rb and Sr diffusion in vitreous silica (13). Such large near-surface concentrations are postulated to result from the exposure at the glass surface of a greater number of interstices or defects over which diffusion can occur. This would lead to steep penetration curves observed in some XPS profiles of glass. 

Metallized Mylar was soaked in bidistilled water for three weeks before the XPS profiling. A dry sample was also analyzed for comparison purposes. The profile of the treated film showed the growth of stoichiometric AI2O3 on the surface of the A1 film. ... 

From Fig. 1. one clearly sees that the XPS profiles of both oxygen and A1 are drastically changed when the sample was soaked in water (21 days). At the uppermost surface, there is a thin layer of carbon contamination above large aluminum oxide consisting of 3 layers of different composition. 

A Mylar film was contaminated with NaCl and dried in air before metallization. XPS profiles were carried out in different areas of these samples. Observations by optical microscope were also made in reflexion and transmission modes. 

The XPS profiles were performed on white spots visible in the NaCl contaminated sample. As one can see from the profiles presented in Fig. 3. the A1 surface of the NaCl contaminated sample does not present major differences compared to the surface of the reference sample. However, drastic changes between the two samples are observed at the interface and in the bulk of A1 ... 

Upon X-ray exposure of a NPPTMS multilayer film (Mg K emitting at 1253.6 eV operated at 15 kV and 20 pA), X-ray photoelectron spectroscopy (XPS) elemental composition data suggested chemical modification of nitro groups to primary amine functions. The N (Is) XPS profile of NPPTMS SAMs as a function of irradiation time is shown in Fig. lb. It can be observed that the pristine peak with a binding energy at 405.6 eV, characteristic of the NO2 moiety [13], diminishes in intensity with elapsed time. Concomitantly, a new peak... 

The zone-selective XPS (ZPS) technique is able to distill the coordination-resolved electronic binding energy of adatoms or at sites surrounding defects, surfaces, interfaces, and solid skin with and without adsorption [21]. The ZPS is obtained by subtracting from the XPS profiles collected from the conditioned surfaces the referential XPS spectrum collected from the ideally perfect surface of the same substance. Before subtraction, all spectral peaks are background corrected and... 

Figure 30.8b illustrates the evolution of the XPS profiles of a particular energy level upon interface formation. The peak v(B) evolves into the v(I) upon alloy formation by heating the heterogeneous layered film to a certain temperature. The y(I) can move upward (polarization, y < 1) or the otherwise. A subtraction of the y(B) from the v(D upon structural area normalization results in the residual spectrum that is purely the interface effect—quantum entrapment or polarization dominance. 

Support for the hypothesis that the polymer produced within a zeolite lattice is partially charged is provided by the XPS profile displayed in Fig. 4, which displays the Nls profile obtained after exposure of cesium-mordenite to pyrrole at 295 K. The major peak at 400.5 eV can be assigned to a neutral nitrogen species in an aromatic polypyrrole chain (79,55), whereas the high-energy 402.5 eV peak is typical of a positively charged nitrogen... 

Fig. 4 Sub-band analysis of the XPS profile obtained after exposure of copper-exchanged mordenite to pyrrole vapour at 295 K.

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