Detection and discrimination of volatile organic compounds using a single multi-resonance mode piezotransduced silicon bulk acoustic wave resonator (PSBAR) as virtual sensor array

This paper describes the detection of volatile organic compounds (VOCs) using an e-nose system based on a virtual sensor array (VSA). The VSA was realized by seven different resonant modes of a single piezotransduced silicon bulk acoustic wave resonator (PSBAR) which can greatly reduce the complexity of a conventional e-nose system. The PSBAR was designed and fabricated using standard CMOS compatible process. The resonant modes of the PSBAR and its capability of VOCs discrimination were theoretically explored through finite element analysis. The discrimination effect was enhanced by the non-uniform adsorption of gas molecules on the top, side and bottom regions of the resonator. Score plots and radar fingerprints obtained respectively from principal component analysis (PCA) and fitted coefficient of adsorption isotherms for each VOC compose sufficient information to successfully discriminate different VOCs. The proposed novel VSA shows great potential as a compact and promising e-nose system.