An 8-channel CMUT chemical sensor array on a single chip

Capacitive Micromachined Ultrasonic Transducers (CMUTs) can be used as small, highly sensitive chemical sensors in air. Single CMUT chemical sensors lack selectivity, but arrays of multiple sensors can be used to allow selective chemical detection. In this work, we demonstrate the simultaneous operation of eight CMUT chemical sensors on a single chip. We then use seven sensors from this array to classify five different chemical vapors and measure their concentrations. Finally, we use the same sensor array to classify three samples of coffee beans grown on different farms. The sensor array is able to perform both classification tasks with 100% accuracy, demonstrating its selectivity.