Percolation model of adsorption-induced response of the electrical characteristics of polycrystalline semiconductor adsorbents

Abstract

A percolation model of the adsorption-induced response of the electrical characteristics of semiconductor gassensitive adsorbents has been developed. It has been shown that in the case of barrier-disordered polycrystalline semiconductor adsorbents both the steady-state and transient responses of the electrical conductivity due to adsorption can be explained by alterations in the heights of intergrain barriers as well as by a change in the degree of barrier disorder. On the basis of the approach developed to explain adsorption-related modification of the height distribution function of the intergrain barriers, we have investigated the adsorption response of oxide composite adsorbents. A qualitative explanation of the anomalously high adsorption sensitivity of such composites characterized by definite composition has been proposed. Our theoretical predictions have been compared with the available experimental data.