Different forms of chemisorption on semiconductors

Abstract

Landsberg trapping statistics were applied to the problem of the different forms of chemisorption of a given gas species on a solid surface. A simplification of the grand partition function yields explicit formulae for the relative contents of the different forms. The probability that the chemisorbed particle will be in a particular state (characterized by a certain type of bond with the surface) was found to be determined by the position of the Fermi level at the surface. The variation of the relative content of the different forms of chemisorption with the changes in the Surface free carrier concentrations has been studied. Other conditions being equal, the position of the Fermi level was found to determine the reactivity of the surface in relation to particles of a given kind. The low value of the maximum attainable coverage predicted by early theories has been discussed, and it was found that the maximum coverage could be considerably higher than predicted, due to the inclusion of the neutral form of chemisorption.