Single Suspended CuO Nanowire for Conductometric Gas Sensing

We present a novel method for integrating single CuO nanowires as gas sensing components in a suspended configuration. In these devices, the nanowire surface area that is actually exposed to the surrounding gas atmosphere is increased, which is favourable when operating the nanowire as conductometric gas sensor. CuO nanowires bridging two adjacent Cu structures were contacted using a thermal oxidation process leading to growth of copper oxide around the nanowire. By this method, linear IV characteristics could be achieved showing the Ohmic contact properties. The sensitivity of the suspended CuO nanowire devices towards humidity and CO was investigated. High signal changes up to 60% were measured in the presence of humidity while small concentrations of CO down to 1 ppm could be detected validating the excellent sensing performance of the presented devices.