Electronic Nose based on MOS Nanowires Gas Sensor Array for Breath Analysis Application

Inspired by the mammalian olfactory system, artificial olfactory (also known as electronic nose) have been developed based on cross-reactive sensor arrays that interact differentially with target molecules to generate a fingerprint pattern recognition which is realized by artificial intelligent technology. Oxide semiconductor chemical gas sensors have many irreplaceable advantages, such as high and unique response to various gases, reversibility, simple structure, silicon compatibility, easy miniaturization and cost-effectiveness. They are an excellent platform for realizing complex and integrated artificial olfaction. This work applies a facile electrospinning method and electrode beam lithography method to develop the four different metal oxide semiconductor (MOS) nanowires sensor array. The dynamic sensing response of the fabricated multiple nanofibers sensor array was measured for human breath. The time serial resistance of each sensor was recorded. Considering that gas sensors with different oxide materials have different responses to kinds of gas molecules, their characteristics are calculated through the obtained time series resistance change curve, including resistance change, response, and recovery time. The breath analysis demonstration video clearly shows that when the fabricated sensor is exposed to human breath, the voltage suddenly decreases, indicating that the resistance of the fabricated gas sensor decreases. It shows the possibility of applying gas sensors in breath analysis to identify the VOCs in the exhaled human breath. The practical applications of gas sensors are determined by their sensitivity, stability, and selectivity. However, it is unclear whether the fabricated gas sensor can produce a stable response to tiny changes in the gas concentration, as well as whether the sensor array can specifically identify different gas components. These aspects should be studied in detail in the future.