Design, Simulation and Optimization of Metal Oxide Sensor for Ammonia Detection Using Nanowires

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 is a sought-after technology for various reasons. In this paper, we present a method of detecting ammonia gas using titanium oxide nanowire based gas sensor. The basic principle of operation was adsorption of gas on to the sensing substance. This happens only at elevated temperatures which are provided by a micro hotplate. The aim was to increase the sensitivity of the sensor and to reduce the power consumption. Surface resistance, which varies due to interactions of gas and oxide, was taken as a measure to calculate the concentration in the ambience of sensor. COMSOL multiphysics tool was used for the performance analysis of the sensor.