Nanolayer Research || Nanolayer Analysis by Photoelectron Spectroscopy

摘要： Photoelectron spectroscopy (PES), or photoemission spectroscopy, is one of the most important and useful techniques for investigating electronic and chemical states in solids, especially in nanolayers because of its high-energy resolution and surface sensitivity [1–5]. The physics behind PES is an application of the photoelectric effect. Through photoelectric ionization by irradiating samples with X-rays, vacuum ultraviolet (VUV) or ultraviolet (UV) light, the energies of the emitted photoelectrons are characteristic of their original electronic and chemical states. Therefore PES is one of the most sensitive and accurate techniques for measuring the energies and shapes of electronic states and molecular orbitals. X-ray photoelectron spectroscopy (XPS) was developed by Kai Siegbahn in 1957 and is used to study the energy levels of atomic core electrons, mainly in solids. Siegbahn referred to the technique as electron spectroscopy for chemical analysis (ESCA), since chemical structure can be determined by analyzing the core levels with small chemical shifts depending on the chemical environment of the atom. Siegbahn was awarded the Nobel Prize in Physics in 1981.