VOCs sensors based on bulk acoustic resonators: a comprehensive review

In this paper, the hazardous effects of various volatile organic compounds (VOCs) on human health and its detection methods have been discussed. This paper also presents the comprehensive study on various VOC sensing mechanisms, their advantages, limitations and key design challenges. It is also reported that acoustic wave sensors are more suitable for VOC detection because of its various advantages as compared to other techniques such as, extended lifetime, miniaturization, high sensitivity, less/zero secondary pollution, low power consumption, lower detection limit and low-cost. The main focus of this paper is on bulk acoustic wave (BAW) devices for VOC detection. The development of film bulk acoustic wave resonators (FBARs) in various aspects such as, structural classification, operating modes, selection criteria of materials (electrode, piezoelectric and sensing layer) and their deposition methods, fabrication process flow and applications have been discussed in this detailed review. Various performance enhancement methods for efficient VOC detection using FBARs have been described in detail to design, model, analyze and optimize a FBAR sensors for the detection of various hazardous VOCs with enriched sensitivity and selectivity.