Fabrication of ZnO thin film based humidity sensor with fast response by sol-gel associated to spin coating method

In the present work, thin films of zinc oxide (ZnO) were deposited by sol-gel associated to spin coating method. Sol was prepared using zinc acetate, 2-Methoxyethanol and monoethanolamine (MEA) as starting materials. Films were grown using solgel method associated to spin coating method. ZnO films morphology was investigated by Scanning Electron Microscope. SEM images reveal that films are composed with wrinkles network. Crystalline structure was studied by means of X-ray diffraction analysis. XRD patterns exhibit three strong peaks (101), (002) and (100) planes assigned to Wurtzite structure. The obtained results for electrical properties were reported. Relative humidity sensing properties has been studied and determined by variation of electrical resistance measurements at various humidity levels. Stability behavior of ZnO wrinkle network humidity sensors has been studied by exposing the sensor to air for 60 days. Our experimental results show that the temperature has strong influence on the response and recovery times of sensing.