Concepts and Principles of X-ray Photoelectron Spectroscopy (XPS)

X-ray photoelectron spectroscopy (XPS) is an analytical technique that uses photoelectrons excited by X-ray radiation (usually Mg Kα or Al Kα) for the characterization of surfaces to a depth of 100 A°. Elemental identification and information on chemical bonding are derived from the measured electron energy and energy shifts, respectively. The use of ultrahigh vacuum (UHV) during analysis requires special sample handling. Depth profiling is possible using ion sputtering. Technological developments in electronics, nanotechnology, polymers, biotechnology, and medicine are all concerned with surfacerelated phenomena, suggesting sustained interest in XPS in the foreseeable future.