SAW gas sensors with titania nanotubes layers

A surface acoustic wave (SAW) sensor with titania nanotubular layer as the gas sensitive material has been developed. This SAW 433 MHz two-port resonator has been fabricated on ST-cut quartz substrate and functionally characterized as an oscillator in dual differential mode. Solvent-casting coatings of anodized TiO2 nanotubes have been used for coating the devices for room-temperature detection of Volatile Organic Compounds (VOCs) including methanol, ethanol, acetone and m-xylene as well as hydrogen gas. The results demonstrate linear responses and high sensitivity of these sensors with the largest sensitivity achieved for ethanol to be 156 kHz/ppm at room temperature.