Capacitively coupled contactless conductivity detection (C4D) of ZnO nanostructures gas sensor by adding Au:Pd metal with response to ethanol and acetone vapor

Abstract

In this work, we present a new gas sensor detection method using the capacitively coupled contactless conductivity detection (C4D) technique. The ZnO nanostructures were prepared by the current heating technique and then added Au: Pd nanoparticles on their surface by a sputtering technique. The gas detector with a C4D system had been fabricated. A data acquisition system was designed to record the signal obtained from the detection electrode. The sensing properties of the sensor with different gas vapor concentrations and operating temperatures have been investigated. Sensitivity was defined as the ratio of signal data in air and vapor gas ambient. The results found that the signal data depend on gas concentration and temperature. However, the results showed lower sensitivity than other techniques, such as the resistive ZnO gas sensor. Finally, the gas sensing mechanism in terms of surface charge density was proposed and used to explain the sensitivity enhancement of C4D ZnO gas sensors.