Dependences of Characteristics of Sensors Based on Tin Dioxide on the Hydrogen Concentration and Humidity of Gas Mixture

Abstract

An expression is obtained for the energy band bending eφ_sH on the surface of the SnO₂ film in the clean air + hydrogen mixture. It is assumed that the value of eφ_sH depends not only on the surface charge density of adsorbed oxygen ions O^¯, but also on the negative charged hydroxyl groups (OH^¯). The results of the analysis of the dependences of eφ_sH on the hydrogen concentration \( {\mathrm{n}}_{{\mathrm{H}}_2} \) and the absolute humidity of the gas mixture obtained during the operation of the sensor in the thermo-cyclic mode are presented. A method for the determining \( {\mathrm{n}}_{{\mathrm{H}}_2} \) in the examined gas mixture is proposed. The method based on the dependence of eφ_sH on the hydrogen concentration established during the calibration of the sensor is proposed. The dependences of the energy band bending on the SnO₂ surface at \( {\mathrm{n}}_{{\mathrm{H}}_2} \) = 0 and the conductivity of the sensor on its temperature during the heating period are discussed.