Highly sensitive and rapid NO_2 gas sensors based on ZnO nanostructures and the morphology effect on their sensing performances

摘要

ZnO nanostructures with different morphologies (nanoparticles, nanorods) have been synthesized using different methods including chemical vapor deposition (CVD) and Sol-Gel. The obtained ZnO nanostructures have been characterized with TEM, SEM, XRD and XPS. Thick films based on the prepared ZnO nanostructures were coated on alumina substrates fitted with gold electrodes and a platinum heater. The responses to NO_2 (≤ 1 ppm) of the different types of ZnO sensors have been studied at working temperatures ranging from 200 to 320°C at 50% of relative humidity. The effects of the synthesis method and the morphology of the ZnO particles on the electrical properties and sensing performances (responses, response and recovery times) of the sensors were demonstrated.