Dear Dr. Sameera Perera,

One of the fundamental assumptions on mathematical definition of XPS spectra is that the sample under study is homogeneously distributed over a scanning area. When you use destructive depth profiling, where energetic ion beam is used to remove material from a sample surface, it is possible to form pits and craters on the sample surface leading to inhomogeneous surface and sometime even to unwanted chemical interactions. XPS spectra obtained from such a damaged sample sometime might lead to a false interpretation of compositional distribution in the sample.

There are different factors like incidence angle of the beam, ion energy etc. that define how material is removed during ion beam and material interaction. This is discussed in detail in the book suggested by Pierluigi Traversi.

You can also read these journal articles, which talk on sputtering effects on XPS spectra during depth profiling,

Article Influence of sputter damage on the XPS analysis of metastabl...

https://www.nature.com/articles/s41598-018-26734-5

Best regards,

Thanks so much for your responses Pitambar Sapkota and Pierluigi Traverso