A SAW hydrogen sensor based on decoration of graphene oxide by palladium nanoparticles on AIN/Si layered structure

This work proposes a surface acoustic wave (SAW) hydrogen sensor based on the decoration of graphene oxide (GO) by palladium nanoparticles on AIN/Si layered structure. A thin decoration of GO by palladium nanoparticles layer is directly coated on the sensor surface as sensing layer. The SAW hydrogen sensor shows higher sensitivity (~9.5 times) and lower cross-sensitivity towards NO 2 compared to those based on GO only. The hydrogen sensor has good stability and fast response. The response time and recovery time are both 7 s. The frequency shift of the sensor with hydrogen concentration change is described by a fitting formula. Response mechanism is investigated based on complex impedance spectroscopy at various hydrogen concentration levels.