XPS- UPS-Auger / X-RAY & UV photoelectron spectroscopy, AUGER electron spectroscopy

X-ray Photoelectron Spectroscopy is a non-destructive surface sensitive technique for solid surfaces. It is based on the kinetic energy analysis of photoelectrons, which originate mainly from the core levels of the atoms in a solid, when this is exposed to x-rays (hν=1-1,5 KeV). The Kinetic Energy of the peaks in an XPS spectrum characterizes the kind of atoms [qualitative analysis] and their chemical environment on the surface [chemical shifts]. The peak area gives information about the atomic concentration or stoichiometry [Quantitative analysis]. In case of multilayer thin films (total thickness<10nm), the thickness of each interlayer can be determined.

Similar to XPS, Ultra violet photoelectron spectroscopy (UPS), using UV radiation (hν=10-45 eV) the valence levels can be examined. The Work function of the materials and the Ionization Potential of organic materials can be determined.

In Auger Electron Spectroscopy (AES) electrons that originate from Auger transitions are detected and recorded, according to their Kinetic Energy, when a solid surface is illuminated by an electron beam (10³ - 10⁵ eV). The chemical shifts give information about the type of the chemical bonds and about the charge transfer on the surface.

XPS/AES can be used for depth profiling in combination with the ion-sputtering gun.