Design, Simulation and Optimisation of an Arrayed Gas Sensor using Metal Oxide based Nanowires

摘要

The levels of toxic gases are increasing enormously in the atmosphere, thereby causing adverse effects on the health of all living beings. There are various toxic gases like ammonia, oxides of nitrogen etc., which have to be detected and eliminated even if present in minute concentrations. Metal oxide based sensors are a sought-after technology for various reasons. Metal oxide gas sensors detect gases based on surface reactions. The rates of adsorption vary with type of gas, oxide and atmospheric conditions. When gas molecules react with the oxide, due to reduction-oxidation reactions the conductivity of the oxide changes. The change in conductance of the substance is taken as a parameter to determine gas in sensor ambience. A gas can be sensed only at elevated temperatures which are provided by a special layer called micro heater within the sensor. The sensitivity of sensor changes with temperature, humidity, surface area etc., present in its ambience. This paper presents the idea of detecting carbon monoxide and ethanol gases using zinc oxide and nickel oxide as sensing materials. Further, the idea of detecting multiple gases was also established using arraying. In arraying individual sensors are grouped to detect their corresponding gases in any proportion. Nanowires were implemented to increase the sensitivity. COMSOL Multiphysics v5.2was the tool used for simulation purposes.