SAW gas sensors with metal oxides nanoplatelets layers

A surface acoustic wave (SAW) gas sensor incorporating metal oxides nanoplatelets layers as chemically interactive material is presented. SAW two-port resonators fabricated using a ST-cut quartz substrate were used as an oscillators in dual differential mode operating at the resonant frequency of 433.92 MHz. Anodized WO3 and evaporated MoO3 nanoplatelets were drop casted onto the SAW microdevices for room-temperature detection of Volatile Organic Compounds (VOCs) such as methanol, ethanol, acetone and m-xylene. Response of the device to hydrogen was also investigated. While operating at room temperature, for MoO3 nanoplatelets layers the highest sensitivity of 14 Hz/ppm was obtained for methanol sensing, and the highest ethanol sensitivity of 79.6 Hz/ppm measured using WO3 nanoplatelets.