Room-temperature NH3 sensors with high sensitivity and short response/recovery times

Micro-sensors are fabricated by co-electrospinning In₂O₃ and SnO₂ nanofibers on the substrates of SiO₂/Si with interdigitated Pt signal electrodes. The total sensor area is 1.36 mm × 0.55 mm and the active area is only 0.63 mm × 0.55 mm. Excellent NH₃ sensing properties are obtained based on the sensors at room temperature. The sensitivity is at most 28 when the sensors are exposed to NH₃ of 10 ppm. The response time is 8 s or so and the recovery time is nearly 2 s. Not only fine selectivity, but also long-time stability is obtained. The results not only demonstrate the obtained micro-sensors are very promising devices for NH₃ detection, but also show a possible route for large-scale NH₃ sensor fabrication at the industrial level.