A high-performance NO₂ gas Sensor Based on Silicon Nanowire Array

Nitrogen dioxide (NO₂) gas detection is crucial for atmospheric environmental safety, industrial production monitoring, and traffic exhaust emission control. Reported detection devices often suffer from poor portability, insufficient selectivity, and demanding application requirements. Herein, we present a portable high-specificity and sensitivity NO2 gas sensor based on silicon nanowire array field-effect transistors (SiNW FETs). The NO2 gas sensor is fabricated on a (111) silicon-on-insulator (SOI) by the standard MEMS technology, which achieving high consistency in the dimensions of silicon nanowires. The experimental results demonstrated that the as-fabricated NO2 gas sensor has a high sensitivity of 20 kΩ/ppm and a detectable minimum NO2 concentration of 1.31 ppm. In addition, the NO2 gas sensor exhibits a remarkable specificity, as evidenced by its significantly higher response to NO₂ compared to SO2, CO, NH3, O3, C₂H₅OH and air. The developed portable sensor signal processing system achieves real-time monitoring and display of NO2 concentration in the atmosphere. Furthermore, this research provides a high precision, easy installation and low cost NO2 detector, indicating a good potential for industrial and civil applications in the future.