In X-ray Photoelectron Spectroscopy (XPS) or Electron Spectroscopy for Chemical Analysis (ESCA), surfaces are irradiated with soft X-rays and the emitted photoelectrons energy analyzed. The difference between the X-ray energy and the photoelectron energies gives the binding energies (BEs) of the core level electrons, an atomic characteristic. What information can ESCA give you?

• Chemical identification and composition
• Chemical state
• Depth distribution