How to analyze and interpret XPS data for charge state determination? what other results can we get from it? If a compound is doped by replacing one element by other, then in XPS data we get the content of dopant as 33% or 45%. May I know with respect what this content is? As being dopant this much cannot be the concentration of dopant in whole compound.
-Charge state: the peak position is sensitive to that. That means, that a similarly charged atom will always be found at a similar binding energy. A good starter is the NIST XPS database. Some entries there are a bit off since the authors sometimes included a not-so-accurate charge compensation or calibration, but to get a general idea what you might have it's enough.
-Concentrations: in order to get absolute concentrations, all atomic species in the substance need to be included, of course. While XPS stoichiometries are not 100% accurate, the result should be in the correct range at least. For more on the quantitative analysis, I like to recommend the Omicron manual starting on page 67:
http://uhv.cheme.cmu.edu/manuals/M470101.pdf
or for more details also the CasaXPS manual.
Shohaib Abass
The main point I would make is that XPS is a surface sensitive technique. As such, 5 - 10 atomic layers would typically be examined. This is not a bulk composition (as 33% or 45% may suggest). You will find the surface to be full of fully-oxidized species and carbon (often the C 1s peak at 285 eV is used for 'charge correction' but this is somewhat controversial these days). Further, the surface will be enriched in those species which will be pulled to the surface with chemisorption induced segregation (caused by O2 in the air) and minimization of Gibbs Free Energy. Indeed, in a mixed system, the bulk and surface compositions cannot be the same... As a good example, in PdAu systems we invariably find enrichment of Pd on the surface in comparison to the bulk composition. Ar+ etching may be needed to probe below the surface into the bulk composition. I would hesitate to call a composition of 33 or 45% of a species to be 'doping'. Doping may only change the XRD pattern slightly - 33 or 45% will almost certainly mean significant changes to the lattice constants. If you want the content of species (and the chemistry - which you do not state - is vital) I'd be removing the materials (say with acid or aqua regia) and then analyzing with AAS or ICP.
Shohaib Abass
You may refer to the answers given by fellow researchgate members Alan F Rawle and Jürgen Weippert since they well addressed the query raised by you. All the best with your research work.
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