Modeling of a p-type resistive gas sensor in the presence of a reducing gas

The detection mechanism in gas sensors based on semiconductor materials is mainly due to charge-transfer. The interaction between the semiconductor surface and the gas is approached by the theory of chemisorption. Based on the Wolkenstein adsorption model, we propose a model simulating the reaction between the ionized oxygen species adsorbed at the surface of a p-type semiconductor with a reducing gas as a function of: (i) work temperature; (ii) oxygen pressure; (iii) gas concentration; and (iv) characteristic properties of the semiconductor/gas interaction. The influence of the main parameters of the model on sensor performance is analyzed through the response curve as a support tool for the design and optimization of suitable materials for a desired sensing application.