Enhanced NO Sensitivity in Schottky-Contacted n-Type SnS Gas Sensors.

Layered materials are highly attractive in gas sensor research due to their extraordinary electronic and physicochemical properties. The development of cheaper and faster room-temperature detectors with high sensitivities especially in the parts per billion level is the main challenge in this rapidly developing field. Here, we show that sensitivity to NO () can be greatly improved by at least two orders of magnitude using an n-type electrode metal. Unconventionally for such devices, the ln() follows the classic Langmuir isotherm model rather than as is for a p-type electrode metal. Excellent device sensitivities, as high as 13,000% for 9 ppm and 97% for 1 ppb NO, are achieved with Mn electrodes at room temperature, which can be further tuned and enhanced with the application of a bias. Long-term stability, fast recovery, and strong selectivity toward NO are also demonstrated. Such impressive features provide a real solution for designing a practical high-performance layered material-based gas sensor.