A Quartz tuning fork-based humidity sensor using Nanocrystalline Zinc oxide thin film coatings

This paper describes an application of quartz tuning forks (QTF) coated with nanocrystalline ZnO films used as relative humidity sensors. The nanocrystalline ZnO thin films were deposited on the QTF by sol-gel method. The film was characterized by X-Ray Diffraction (XRD) and Atomic Force Microscope (AFM) to obtain the information on the structural and morphological properties. And the humidity sensitivity characteristics of the sensors have been investigated. Ethanol and acetone interference on the sensor performance have been also tested. Sensing experiments were examined by measuring the resonance frequency shift of QTF which due to the additional mass loading. The results showed that the sensors have high humidity sensitivity, good stability, fast response time, and well reproducibility. We demonstrate here a simple and low-cost humidity sensor using the QTF