With the advent of smartphones and ubiquitous monitoring devices, there has been a high hope for miniaturized chemical sensor chip that could monitor hazardous chemicals, pollutions, our breath for lung cancers, and freshness of food. To meet these demands, many gas sensor platforms from nano to micron size have been proposed.
What is problem and why is it important?
Miniaturized chemical sensors have been developed over two decades yet a practical portable chemical sensor system in the size of smart watch has not been demonstrated. Practical sensor system should be not only sensitive, but also reliable, reproducible, and not prone to cross-talk. However, while many previously reported miniaturized chemical sensor systems exhibit high sensitivity through optimization of sensor devices, application of nano materials to increase surface area, and reduction of noise of read-out circuits, these systems still lack the required selectivity and is subject to environment noise and interference chemicals.
Our approach to achieve a practical sensor system is through massive parallelism with pattern tracking. Based on the advantages of small size, reliable manufacturing, high sensitivity, and array structure, we use Capacitive Micromachined Ultrasound Transducers (CMUTs) as chemical sensors.