Influence of Nano Zinc Oxide Treated by HMDS in Humidity Detection

QCM-based gas sensors are potential for applications due to its simple structure and high sensitivity. But the low selectivity attributed to the environment factors need to be concerned such as the variations of humidity and volatile organic vapors. In this paper, humidity sensitive properties of HMDS treated nano zinc oxide was researched. The work can be divided into two sections: First, the sensing properties of nano zinc oxide were studied by quartz crystal microbalance (QCM) in relative humidity detection. The results showed that the nano zinc oxide film had high humidity sensitivity and well reproducibility. Second, the humidity sensing properties of nano zinc oxide treated by Hexamethyldisilazane (HMDS) were also investigated. It is found that the humidity sensitivity of nano zinc oxide treated by HMDS was much lower than untreated ZnO, especially in high relative humidity environment. The experiment results indicate that the HMDS treated by nano zinc oxide can be used to detect the ethanol in high humidity environment.