AES

AES (Auger electron spectroscopy) is a spectroscopic method based on the Auger effect: if an electron receives sufficient energy from one of the inner shells (e.g. from an electron), it is released from the atomic shell. Due to its low energy level, the vacated space is reoccupied by an electron from a higher energy level. The energy released in this process can be transferred to another electron, which leaves the atom as an Auger electron. The energy of the emitted Auger electron depends on the energy levels of the atom involved. It results from the energy level of the original unoccupied state, the initial level of the electron that fills the state and the initial level of the Auger electron.

Auger electron spectroscopy is a very surface-specific method. The recorded material layer usually only comprises the top ten atomic layers. The method is therefore very efficient for locally high-resolution detection.