Research of the interaction mechanism between HCl and semiconductor metal oxides

Gas-sensitivity was investigated of n- and p-types conductivity semiconductor sensors based on zinc, indium and chrome oxides with the respect to hydrogen chloride (0.06 – 3 ppm). Disclosed were two mechanisms of interaction between НС1 and above metal oxides. It is demonstrated that HCl chemisorption results in decrease, and chlorine generation by HCl oxidation results in increase of semiconductor sensor resistance of n-type conductivity. Inverse relationship is observed for sensors with p-type conductivity. Calculation results of НСl conversion degree under the conditions of thermodynamic equilibrium of the reaction of HCl to Cl2 oxidation are in good agreement with the experimental results for different sensor temperatures, gas humidity range and oxygen content.