부산대학교 도서관

The uniformity and repeatability of sensing film will greatly affect the sensor-to-sensor reproducibility. In this paper, an ethanol sensor based on a surface acoustic wave (SAW) resonator and uniform ZnO nanoparticles-reduced graphene oxide (rGO) composite film as sensing material was proposed. A uniform ZnO-rGO composite film was firstly formed by vacuum filtration and reduction and then transferred to the SAW ethanol sensor. This film formation and transfer process has very good repeatability and stability, as evidenced by the response of the sensors. Benefitting from the uniform composite film, the ethanol sensor shows advantages of wide response range (0~70 vol%), excellent short-term repeatability, good stability, fast response (23 s) and recovery (18 s). Moreover, a dual-mode detection method was proposed to discriminate different gases through simultaneously detecting the mechanical (resonant frequency, ${f}$ ) and electrical (impedance, ${Z}$ ) responses of the same gas adsorption based proposed sensor. To the best of our knowledge, this is the first report on SAW sensor based on uniform ZnO-rGO composite film formed by vacuum filtration and reduction.