Influence of CuO nanostructures morphology on hydrogen gas sensing performances

In this study, the impact of different morphologies of p-type copper oxide nanostructures on hydrogen gas response is investigated. Sensor structures based on CuO nanowire (NW) networks demonstrated much higher gas response (similar to 340) than nanostructured films (similar to 3) at operating temperatures of 300 degrees C. Such a high gas response in the case of CuO NW networks is explained by percolating phase transition of CuO NW surface to metallic Cu. The phenomenon is observed at operating temperatures higher than 275 degrees C, but show good reversibility at 300 degrees C. At a higher operating temperature of 400 degrees C, the gas response was found lower (similar to 108) than at 300 degrees C, even if the response time and percolating time were much shorter. On the other hand, the faster recovery time (similar to 2 s) to the initial value of electrical baseline was observed at an operating temperature of 300 degrees C. This latter temperature is found the best regime for stable and highly sensitive and selective detection of hydrogen with high repeatability for sensor structures based on CuO NW networks. These results will help to take full advantage of these functional nanomaterials in the new generation of sensorial nanodevices for their larger scale utilization. (C) 2016 Elsevier B.V. All rights reserved.