An ammonia gas sensor based on non-catalytically synthesized carbon nanotubes on an anodic aluminum oxide template

In this study, an ammonia gas sensor structure for mass production is realized with an array of carbon nanotubes synthesized on an anodic aluminum oxide (AAO) template. The device is expected to yield a uniform performance due to the regular and uniform nano channels in the AAO. It is a vertical structure made with open-ended multi-wall carbon nanotubes through deposition on the inside wall of the AAO so that the gas would diffuse into the nano channels for adsorption. The carbon nanotubes are in the form of flaked carbons having many defect sites. The results show that the sensor has high sensitivity, fast response time of less than 1 min and good reproducible recovery behaviors in atmospheric pressure at room temperature.