Simultaneous Detection of NH₃ and NO₂ by Modified Impedance Spectroscopy in Sensors Based on Carbon Nanotubes

Abstract

There are many gaseous substances that need to be monitored for possible damage to health or the environment. This requires many sensors. The solution to reducing the number of sensors is to use one sensor to detect several gaseous substances simultaneously. Efforts to simplify sensor systems thus lead to the use of a sensor with a suitable sensitive layer and to finding a suitable method of detecting individual gaseous substances within one sensor. The aim is to find a suitable method to detect various gaseous substances acting on the sensor. For this purpose, modified impedance spectroscopy in the high-frequency range is applied, where the scattering parameters of the sensor based on carbon nanotubes are measured under the action of NO2 and NH3 gases. For this method of detection of gaseous substances, a suitable sensor platform structure was designed to enable the measurement of the electrical properties of the sensor in the GHz range. Based on the obtained results, it is possible to use one sensor to detect different types of gaseous substances.

Keywords

• impedance spectroscopy
• scattering parameters
• sensor
• gas detection
• carbon nanotubes