Mathematical modeling the polycrystalline layers conductivity of wide-bandgap semiconductors during adsorption on their surface of gases-reducers in the presence of oxygen

Abstract

The results of the response study of gas sensors based on gas-sensitive layers Cu:SnO2 to ethanol, acetone, and 2-propanol vapors are presented. Sensor response concentration dependencies are measured at different temperatures to determine optimal operating modes. Experimental temperature dependence of the sensors response to the vapors of the analyzed substances are determined. The dependence is theoretically substantiated by a proposed mathematical model based on consideration of the processes of transfer of charge carriers through the potential barrier grains of a polycrystalline semiconductor film in an oxygen-containing medium and the reducing gas to be analyzed. It is assumed that each type of gas on the surface of SnO2 has its own adsorption centers. The work shows that the model can be used to calculate and predict the gas sensitivity measurements of sensors based on the active layers of polycrystalline semiconductors. The results of the calculations confirm that such energy parameters as the depth of the energy level and the desorption energies are individual for each substance.

Keywords

• organic matter vapor detection
• semiconductor gas sensor
• tin dioxide
• temperature response dependency
• dissociative adsorption