Fast Nitrogen Dioxide Sensing with Ultralow‐Power Nanotube Gas Sensors

Abstract

Abstract The study reports fast, ultralow‐power operation of carbon nanotube‐based nitrogen dioxide (NO2) sensors enabled by nanotube self‐heating and transient sensing. The self‐heating effect in the nanotube channel significantly accelerates the desorption of gas molecules, reducing the sensor recovery time to a minute. As gas molecules re‐adsorb on the nanotube after cooling, the initial rate of the sensor transient is used to determine NO2 concentration within a few minutes. To accelerate and optimize the operation of the sensor, the study considered temperature profiles along the self‐heated carbon nanotube, their effect on different sensing regions, and a physical model‐based fit. As a result, the nanotube‐based NO2 sensor demonstrates recovery and readout times below 5 min and an extrapolated limit of detection below 10 ppb. The peak power consumption of this operation mode is below 6 µW. The combination of fast readout, fast recovery, low limit of detection, and ultralow power consumption demonstrated in this work shows strong promise of carbon nanotube‐based NO2 sensors in mobile or Internet‐of‐Things (IoT) applications.

Keywords

• carbon nanotube
• nitrogen dioxide (NO2)
• sensor recovery
• transient sensing
• ultralow‐power