ZnO Based Ultrasensitive CO Chemiresistive Gas Sensor

Abstract The detection of hazardous gases in the atmosphere is a topic of interest for public security, environmental pollution and industrial emission. In recent years, semiconductor-based gas sensor attracted wide attention in all over the world. Among various hazardous gases, detection of CO at low temperature with fast response and recovery time is still a challenge. In this work, we have adopted single step synthesis of zinc oxide (ZnO) nanoroads for the fabrication of CO gas sensor. This sensor is found to have ∼8% sensitivity with fast response time of the order of 10 s at 50 °C. Also, selectivity of sensor has been investigated for different gases and observed that ZnO is more active for CO gas at 50 °C. The sensitivity of ZnO based sensor is explained in terms of interaction of CO molecules with adsorbed oxygen vacancies in ZnO which promote better pathway to the charge carrier. The sensing material is characterized by x-ray diffraction (XRD), UV–vis spectroscopy and scanning electron microscopy (SEM). To the best of our knowledge, the detection of 15 ppm CO at 50 ºC with good sensitivity is reported first time.