Fabrication of surface acoustic wave based wireless NO2 gas sensor

Surface acoustic wave (SAW) devices provide a convenient platform for the realization of sensors in the present decade. 99.4 MHz SAW resonator has been fabricated over the ST cut quartz. Subsequently PZT thin film has been deposited by pulsed laser deposition technique as a sensing layer over the fabricated SAW resonator. Shift in resonance frequency was measured precisely for varying concentration of NO2 gas. The calibration curve was found to be linear having a sensitivity of 9.6 Hz/ppm. The fabricated sensor is advantageous for its room temperature, handheld and wireless sensing.