La0.5Sr0.5CoO3-δ nanotubes sensor for room temperature detection of ammonia

La0.5Sr0.5CoO3-delta (LSCO) nanotubes were synthesized by using a porous anodic aluminum oxide (AAO) template from a sol-gel solution. Based on the achievement of synthesis of LSCO nanotubes, a nanotube gas sensor was fabricated with microelectromechanical system technology and its NH3 sensing characteristics were investigated. Capacitance of LSCO nanotubes was changed by two orders of magnitude within several seconds of exposure to NH3 molecules at room temperature. The detection limit of the LSCO nanotube sensor was several ppm, and the typical response and recovery time of the sensor at room temperature was only several seconds. Our results demonstrate the potential application of LSCO nanotubes for fabricating a highly sensitive and fast response gas sensor. (C) 2008 Elsevier B.V. All rights reserved.