ANALYSIS OF ABSORPTION PROCESSES ON THE SURFACEOF A NANOCOMPACTED GAS SENSOR

It is well known that gas absorption by a semiconductor surface leads to a change in its electrical conductivity. This phenomenon has become the basis for the technical production of various gas sensitive sensors. Near the particle surface, due to the absorption and subsequent ionization of oxygen molecules, a surface zone is formed that is depleted in free charge carriers. The thickness of this zone is comparable to the Debye length and depends on the oxygen pressure on the particle surface. Depending on the size of the particle and the degree of their connection, there can be either conductive contacts or contacts of the Schottky barrier type between them. All this leads to a different kind of relationship between the conductivity and the concentration of the gas being determined. Since the sensitivity is based on chemical reactions between the surface of a solid body and gas molecules, the most demanded are materials with a large surface-to-volume ratio and a high degree of porosity, i.e. nanoparticles. In the present work, the main possible mechanisms of absorption of gas molecules by compacted nanoparticles are considered and their analysis is carried out.

absorption, semiconductors, nanocompacted material, gas sensors, simulation