fotoemissioanalyysillä

Fotoemissioanalyysi, also known as photoelectron spectroscopy (PES), is a powerful analytical technique used to study the electronic structure of materials. It works by illuminating a sample with photons, typically from a UV or X-ray source, and measuring the kinetic energy of the electrons that are emitted from the sample's surface. According to the photoelectric effect, the energy of the emitted electron is directly related to the binding energy of the electron in the atom and the energy of the incident photon.

By analyzing the distribution of these emitted electrons as a function of their kinetic energy, researchers can obtain detailed information about the elemental composition, chemical state, and electronic properties of the material's surface. This makes fotoemissioanalyysi invaluable in fields such as materials science, chemistry, physics, and surface science. Different variants of the technique exist, including X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS), each offering unique insights depending on the energy of the photons used and the depth of analysis required. XPS is primarily used for elemental composition and chemical state analysis of the top few nanometers of a surface, while UPS is more sensitive to the valence band structure. The technique is non-destructive in many cases, allowing for subsequent analysis of the same sample.