fotoemisjonselektronmikroskopi

Fotoemisjonselektronmikroskopi, often abbreviated as FEM, is a microscopy technique that utilizes photoemission to generate an electron image. In this method, a sample is illuminated with ultraviolet (UV) or X-ray photons. When these photons strike the sample's surface, they can cause the emission of electrons through the photoelectric effect, a phenomenon known as photoemission. The emitted electrons are then accelerated and focused by electrostatic or magnetic lenses onto a detector, creating a magnified image of the sample's surface.

The primary advantage of FEM is its ability to image the electronic structure of materials. The energy distribution of the emitted photoelectrons can be analyzed, providing information about the valence band structure, chemical composition, and oxidation states of the sample. This makes FEM particularly useful in surface science, solid-state physics, and materials science for investigating phenomena such as catalysis, semiconductor properties, and thin film growth. Resolution in FEM can be on the order of tens of nanometers, depending on the design and parameters of the instrument. It is a surface-sensitive technique, as the emitted electrons originate from the top few atomic layers.