Photoemission spectroscopy platform (XPS & UPS)

The ICN2 photoemission installation houses a state-of-the-art XPS and UPS system that allows the surface, chemical and electronic characterization of a wide range of materials. The facility provides services to both internal and external ICN2 customers. XPS and UPS are surface-sensitive techniques because electrons will travel only a few nanometers in the solid before to lose energy by inelastic interaction, meaning that the analyzed electrons come from the upper surface of the material. That is why, in photoemission spectroscopy, the sample is placed in an ultra high vacuum (UHV) to protect the surface from contamination and allow the emitted electrons from the solids to reach the analyzer. XPS, due to the higher energy of the X-ray source, gives access to the core level allowing the determination of the chemical structure of the materials as the core levels have a small chemical shift depending on the environment chemical of the atom that is ionized. XPS also allows you to quantify the elements present in the material. The UPS, due to the lower energy of UV light, gives access to the electrons of the valence bands and allows, with angular resolution UPS (ARUPS), to observe the distribution of electrons in the reciprocal space of solids.