Explanation

An analytical technique for studying surface crystal structure. The electron diffraction study shows that in order to analyze the two-dimensional crystal structure of the surface layer, the electron beam is required to meet the following requirements: ① the wavelength is short enough to distinguish a single atom; ② There is a strong interaction with matter, and its escape depth is several atomic layers. Low energy (50-500eV) electron beams can best meet the above requirements. The electron diffraction generated from the surface of crystal material by using low-energy electron beam as the microprobe for surface structure analysis is called low-energy electron diffraction. The main equipment is composed of vacuum analysis chamber, electron gun and electron diffraction recording device with post acceleration technology. Compared with other diffraction techniques, it has the following characteristics: ① it can generate diffraction patterns between two-dimensional and three-dimensional; ② It can study any crystalline materials, and the results can be easily compared with the mass spectrometry data; ③ The minimum selection size analyzed is lpm. Therefore, low-energy electron diffraction technology is the main analytical method to obtain the surface atomic structure arrangement information, which is mainly used to study the interface chemical reaction. In addition, it is also widely used in vapor deposition surface formation, oxide film growth, surface diffusion, gas adsorption and catalytic processes.

Classification