X-ray photoelectron spectroscopy measures the elements and their chemical states in the top few nanometers of a surface. Auger electron spectroscopy (AES) analyzes much smaller spots. Typical questions - What is on this surface: residue, oxide, or contamination? - Did the cleaning, plasma, or coating step change the surface chemistry? - What is the chemical state of an element, for example metal or oxide? Good to know - Both techniques see only the outermost few nanometers. - Samples must tolerate high vacuum. - Hydrogen and helium are not detected.
