ZnO nanorod gas sensor for NO2 detection

Vertically aligned ZnO nanorod arrays are prepared by a hydrothermal method with zinc acetate and hexamethylenetetramine, and used for NO2 gas sensing. The NO2 sensor based on nanorod arrays shows a higher sensitivity and lower operating temperature as compared to the sensor based on the ZnO film prepared by ultrasonic spray pyrolysis. The enhanced sensitivity is attributed to the higher aspect ratio of the nanorod structure. The response of the ZnO nanorod sensor is linearly proportional to the NO2 concentration in the 0.2-5.0 ppm range, and the sensitivity of the sensor increases with the length of the ZnO nanorod.