Use of complex impedance spectroscopy in chemical sensor characterization

Abstract The complex impedance method is a powerful tool in the characterization of gas adsorption in semiconductor structures used as gas sensors. Different tin oxide structures have been used. In tests of sensitivity to dry air, air + H 2 O, O 2 , etc, the operating temperature has increased to 175 °C. A variable frequency (10 μHz–32 MHz) a.c. voltage is applied to the sensor structure to perform the complex impedance spectrum measurements. The different parameters are a function of the type of gas in the atmosphere. A model has been proposed based on adsorption on the grain boundary.