X-Ray Photoelectron Spectroscopy (XPS)

 X-ray Photoelectron Spectroscopy is a surface-sensitive quantitative spectroscopic technique. In an XPS experiment, a specimen is irradiated by low energy X-rays in an UHV ultra high vacuum. This causes photo-ionisation of the atoms at the specimen´s surface: photoelectron are emitted from energy levels determined by the electronic structure of the specimen. The XPS analysis technique examined the kinetic energies and number of these photoelectrons that escape from the top 0 to 12 nm of the material analyzed to determine their energy distribution. From the results of this analysis it is possible to infer which elements are present on the speciment, what chemical states are, and in what quantities they are present.