Formation of networked ZnO nanowires by vapor phase growth and their sensing properties with respect to CO

Using a selective growth of ZnO nanowires on patterned electrode layers by using the vapor-phase-growth method, networked ZnO nanowires were fabricated. These networked nanowires were tested as sensors for detecting CO at ppm levels. Good sensitivity and a dynamic property with respect to CO were confirmed in the networked ZnO nanowire sensor. The sensing mechanism is attributed to the change not only in the width of the space charge region along the length direction of each nanowire, but also in the height of the potential barrier at the junction during adsorption and desorption of chemical gaseous species. This novel method to fabricate gas sensors may circumvent the drawbacks of single nanowire gas sensors.