Low-temperature-operated sensitive NO2 gas sensors based on p-type SnO thin-film and thin-film transistors

摘要

We demonstrated a p-type MOS-based thin-film transistor (TFT) nitrogen dioxide (NO2) gas sensor that uses tin monoxide (SnO) for both the channel and sensing layers. The fabricated SnO TFT showed a maximum response value of 19.4-10 ppm NO2 at room temperature (RT) when operated in the subthreshold region, which was significantly higher than the maximum response value of 2.8-10 ppm NO2 obtained with a SnO thin-film chemiresistor at RT. In addition, the SnO TFT gas sensor showed significantly higher sensitivity to NO2 gas than to other target gases such as NH3, H2S, CO2, and CO at RT. To our knowledge, this is the first report on a p-type MOS-based field-effect transistor-type gas sensor. Our experimental results demonstrate that the p-type SnO TFT is a promising gas sensor that can operate at RT with high sensitivity and selectivity to NO2 gas.