Detection of NO2 down to ppb levels using individual and multiple In2O3 nanowire devices

We demonstrate detection of NO$_{2}$ down to ppb levels using transistors based on both single and multiple In$_{2}$O$_{3}$ nanowires operating at room temperature. This represents orders-of-magnitude improvement over previously reported metal oxide film or nanowire/nanobelt sensors. A comparison between the single and multiple nanowire sensors reveals that the latter have numerous advantages in terms of great reliability, high sensitivity and simplicity in fabrication. Furthermore, selective detection of NO$_{2}$ can be readily achieved with multiple-nanowire sensors even with other common chemicals such as NH$_{3}$, O$_{2}$, CO and H$_{2}$ around.