Influence of ZnO morphology on humidity sensing performance based on quartz crystal microbalance

Abstract

Two different morphologies of ZnO synthesized by hydrothermal method were coated on quartz crystal microbalance (QCM). Field emission scanning electron microscopy and X-ray diffraction were used to analyze the morphology and crystal structure of ZnO. The humidity sensing behavior was examined by measuring the resonance frequency shifts of QCM in the whole humidity range from 11 to 95%. The kinetics of adsorptiondesorption and mechanism of humidity sensing were studied. The results show that the morphology of ZnO greatly affects the humidity sensitivity of QCM sensor. Furthermore, the adsorptiondesorption model is also dependent on the morphology of ZnO.