High-performance NO2 gas sensor based on ZnO nanorod grown by ultrasonic irradiation

A facile and fast sonochemical route for the fabrication of a resistive-type ZnO gas sensor has been demonstrated. Vertically aligned ZnO nanorod arrays were grown on a Pt-electrode patterned alumina substrate under ambient conditions. The average diameter and length of the ZnO nanorods were 50 and 500 nm, respectively. Sonochemically grown ZnO nanorod gas sensor was highly sensitive to NO2 gas with a very low detection limit of 10 ppb at 250 °C; further, its response and recovery time were short. Considering the advantageous properties of this sonochemical technique, we believe that it can be used to fabricate high-performance gas sensors.