A Novel Humidity Sensor Based on Circular Interdigital Transducers Excited ALN Lamb Wave Device Incorporating Graphene Oxide Layer

摘要

In this paper, a circular interdigital transducers (IDTs) excited lamb wave humidity sensor with graphene oxide (GO) as sensing layer is firstly reported. The circular IDTs are adopted to deal with lamb wave diffraction problem due to finite aperture of conventional straight IDTs. Test results show the humidity sensitivity of the circular IDTs excited sensor is 1.5 times higher than that of conventional straight IDTs excited sensor within a wide detection range from 10%RH to 90%RH. In addition to excellent stability and repeatability, the sensor also has very little hysteresis, fast response and quick recovery speed. Moreover, utilizing the AIN/Si (doped) layered structure, small temperature coefficient of frequency (TCF) of -19.8 ppm/°C of the sensor is achieved.