Ultralow power consumption gas sensor based on a self-heated nanojunction of SnO nanowires.

The long duration of a working device with a limited battery capacity requires gas sensors with low power consumption. A self-heated gas sensor is a highly promising candidate to satisfy this requirement. In this study, two gas sensors with sparse and dense SnO nanowire (NW) networks were investigated under the Joule heating effect at the nanojunction. Results showed that the local heating nanojunction was effective for NO sensing but generally not for reduction gases. At 1 μW, the sparse NW sensor showed a good sensing performance to the NO gas. The dense SnO NW network required a high-power supply for gas-sensitive activation, but was suitable for reduction gases. A power of approximately 500 μW was also needed for a fast recovery time. Notably, the dense NW sensor can response to ethanol and HS gases. Results also showed that the self-heated sensors were simple in design and reproducible in terms of the fabrication process.